Re: Elecraft Digest, Vol 197, Issue 18
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Re: Elecraft Digest, Vol 197, Issue 18
 
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Sent from my iPhone > On Sep 14, 2020, at 11:03 AM, [hidden email] wrote: > > Send Elecraft mailing list submissions to > [hidden email] > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.qth.net/mailman/listinfo/elecraft > or, via email, send a message with subject or body 'help' to > [hidden email] > > You can reach the person managing the list at > [hidden email] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Elecraft digest..." > > > Today's Topics: > > 1. Why predistortion ? (JR) > 2. Re: Why predistortion ? (Wayne Burdick) > 3. Re: Why predistortion ? (E.H. Russell) > 4. Re: Why predistortion ? (Randy Farmer) > 5. KAT500: Fails to tune, and shows 3:1 on good antenna on 18 > MHz. (Dave Cole) > 6. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Dick Dievendorff) > 7. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Ken Winterling) > 8. Why predistortion ? (John Harper) > 9. Re: Why predistortion ? (Wes) > 10. Re: Why predistortion ? (W2xj) > 11. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Dave Cole) > 12. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Dave Cole) > 13. Re: Why predistortion ? (David Gilbert) > 14. Re: Why predistortion ? (Bill Frantz) > 15. Re: Why predistortion ? (Wayne Burdick) > 16. Re: Why predistortion ? (Jim Brown) > 17. Re: Why predistortion ? (Jim Brown) > 18. Re: Why predistortion ? (David Gilbert) > 19. Elecraft CW Net Report (kevinr) > 20. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Dave Cole) > 21. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on > 18 MHz. (Ken Winterling) > 22. 630 meter operation on the K4 (Nigel Lemaire) > 23. Re: Why predistortion ? (Charlie T) > 24. Re: Why predistortion ? (Charlie T) > 25. Re: Why predistortion ? (Dr. William J. Schmidt) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 13 Sep 2020 17:32:21 -0400 > From: JR <[hidden email]> > To: [hidden email] > Subject: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Why are so many ops obsessed with predistortion? > > The Elecraft K-Line already produces some of the cleanest, purest > transmit signals around.?? Do we need predistortion ?? If so, why, and > how much better is it than what we already have?? Should I wait to buy a > new rig until that is available? > > Thanks and Happy Trails to all.?? K8JHR > _________________________________ > > > ------------------------------ > > Message: 2 > Date: Sun, 13 Sep 2020 15:03:00 -0700 > From: Wayne Burdick <[hidden email]> > To: JR <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Hi JR, > > Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. > > To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. > > A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. > > Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. > > Wayne, > N6KR > > ---- > elecraft.com > >> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >> >> ?Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >> >> Thanks and Happy Trails to all. K8JHR >> _________________________________ >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ------------------------------ > > Message: 3 > Date: Sun, 13 Sep 2020 18:41:52 -0400 > From: "E.H. Russell" <[hidden email]> > To: "'Wayne Burdick'" <[hidden email]>, "'JR'" > <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <006301d68a1f$13ca1b80$3b5e5280$@qrv.com> > Content-Type: text/plain; charset="utf-8" > > Well put. > > TKS, > 73 ED W2RF > > > > > -----Original Message----- > From: [hidden email] <[hidden email]> On Behalf Of Wayne Burdick > Sent: Sunday, September 13, 2020 6:03 PM > To: JR <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > > Hi JR, > > Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. > > To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. > > A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. > > Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. > > Wayne, > N6KR > > ---- > elecraft.com > >> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >> >> ?Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >> >> Thanks and Happy Trails to all. K8JHR >> _________________________________ >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net Please help support this email >> list: http://www.qsl.net/donate.html Message delivered to >> [hidden email] > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] > > > > ------------------------------ > > Message: 4 > Date: Sun, 13 Sep 2020 18:48:17 -0400 > From: Randy Farmer <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > I can testify to the effectiveness of predistortion techniques from my 5 > years or so as a CDMA Cellular Base Station engineer with Motorola. The > first generation of CDMA transmitters had a very specific "spectral > mask" that had to be certified. As I recall, the transmitter output that > met the Spectral Mask requirements of something like -60 dBc outside of > the channel bandwidth showed up with essentially vertical sides (and a > very flat top) on a spectrum analyzer. Obtaining this performance was > neither cheap nor easy, and the associated testing was pretty stringent > as well. Meeting the specs demanded very sophisticated predistortion > techniques. Be glad that conventional SSB and the fairly simple > waveforms used in amateur digital comms don't require too much dynamic > headroom. The first generation CDMA waveform had a roughly 10:1, or 20dB > peak-to-average power ratio. This meant that the transmitters we > designed to produce 20W average power were actually capable of 200W > continuous output power and still met the spectral mask IMD > requirements. Putting multiple carriers through the PA required either > higher power capability or derating the power output for each individual > carrier. I no longer work in the industry, so I don't know what the > current generation of signals requires, but with the greater bandwidths > and more complex modulation schemes used now you can bet the > requirements, and therefore the transmitter design challenge, didn't get > any easier. > > 73... > Randy, W8FN > >> On 9/13/2020 6:03 PM, Wayne Burdick wrote: >> Hi JR, >> >> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >> >> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >> >> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >> >> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >> >> Wayne, >> N6KR >> >> ---- >> elecraft.com > > > ------------------------------ > > Message: 5 > Date: Sun, 13 Sep 2020 15:48:40 -0700 > From: Dave Cole <[hidden email]> > To: [hidden email] > Subject: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Hello, > My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. > Antenna is a single feedline to a 6BTV, and an analyzer says all is good > at low power. At 100 watts, all seems good. > > All other bands seem OK at high power. > > Question: When in bypass, is the entire tuner bypassed? > Question: When turned off is the tuner bypassed? Which antenna is default? > -- > 73, and thanks, > Dave (NK7Z) > https://www.nk7z.net > ARRL Volunteer Examiner > ARRL Technical Specialist > ARRL Asst. Director, NW Division, Technical Resources > > > ------------------------------ > > Message: 6 > Date: Sun, 13 Sep 2020 15:57:03 -0700 > From: Dick Dievendorff <[hidden email]> > To: Dave Cole <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > When unpowered the KAT500 is bypassed, ANT1. > > When the ATU is in mode BYP, yes, it?s bypassed. > > 73 de Dick, K6KR > >> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >> >> ?Hello, >> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is a single feedline to a 6BTV, and an analyzer says all is good at low power. At 100 watts, all seems good. >> >> All other bands seem OK at high power. >> >> Question: When in bypass, is the entire tuner bypassed? >> Question: When turned off is the tuner bypassed? Which antenna is default? >> -- >> 73, and thanks, >> Dave (NK7Z) >> https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ------------------------------ > > Message: 7 > Date: Sun, 13 Sep 2020 19:24:24 -0400 > From: Ken Winterling <[hidden email]> > To: Dick Dievendorff <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: > <[hidden email]> > Content-Type: text/plain; charset="UTF-8" > > When you have issues like this the best test is to use a known good dummy > load. That removes the antenna system from the equation. See what happens > on 18mHz when transmitting into the summy load. > > Ken > WA2LBI > > > > > >> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email]> wrote: >> >> When unpowered the KAT500 is bypassed, ANT1. >> >> When the ATU is in mode BYP, yes, it?s bypassed. >> >> 73 de Dick, K6KR >> >>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >>> >>> ?Hello, >>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. >> Antenna is a single feedline to a 6BTV, and an analyzer says all is good at >> low power. At 100 watts, all seems good. >>> >>> All other bands seem OK at high power. >>> >>> Question: When in bypass, is the entire tuner bypassed? >>> Question: When turned off is the tuner bypassed? Which antenna is >> default? >>> -- >>> 73, and thanks, >>> Dave (NK7Z) >>> https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ------------------------------ > > Message: 8 > Date: Sun, 13 Sep 2020 18:40:01 -0500 > From: John Harper <[hidden email]> > To: Elecraft list <[hidden email]> > Subject: [Elecraft] Why predistortion ? > Message-ID: > <CAPHmH=O3V_u977xn0c9qJ1hCEyxwfdVYMXXhL30QRg=[hidden email]> > Content-Type: text/plain; charset="UTF-8" > > Here's a demonstration of predistortion in use (relevant part starts at the > 10-minute point): > https://www.youtube.com/watch?v=0adHZOTqTlQ > > John AE5X > https://ae5x.blogspot.com > > >> Why are so many ops obsessed with predistortion? > > > ------------------------------ > > Message: 9 > Date: Sun, 13 Sep 2020 17:20:39 -0700 > From: Wes <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > You're kidding, right? > > Wes? N7WS > > >> On 9/13/2020 2:32 PM, JR wrote: >> The Elecraft K-Line already produces some of the cleanest, purest transmit >> signals around.... >> >> Thanks and Happy Trails to all.?? K8JHR > > > > ------------------------------ > > Message: 10 > Date: Sun, 13 Sep 2020 20:24:07 -0400 > From: W2xj <[hidden email]> > To: Wayne Burdick <[hidden email]> > Cc: [hidden email], JR <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > wayne, > > After you have the K4 fully put to bed, for your next project you might want to consider an amp that is directly driven by an I/Q stream. The amplifier will be much more efficient (less power consumption) and you start out with less IMD before any pre-distortion. > > Sent from my iPad > >> On Sep 13, 2020, at 6:05 PM, Wayne Burdick <[hidden email]> wrote: >> >> ?Hi JR, >> >> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >> >> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >> >> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >> >> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >> >> Wayne, >> N6KR >> >> ---- >> elecraft.com >> >>>> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >>> >>> ?Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >>> _________________________________ >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > > ------------------------------ > > Message: 11 > Date: Sun, 13 Sep 2020 17:53:36 -0700 > From: Dave Cole <[hidden email]> > To: Dick Dievendorff <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > That helps triage the issue... Something in my antenna must have gone > wonky... I am using a 6BTV, with the 18 Meter add on kit, so the same > feedpoint is used for all bands, and they are fine... I was worried it > was the tuner. I'll go check the antenna out tonight, and in the > morning as well... THANK YOU! Knowing the tuner is bypassed in Bypass, > helps... Next is to put a dummy load on the tuner... > > 73, and thanks, > Dave (NK7Z) > https://www.nk7z.net > ARRL Volunteer Examiner > ARRL Technical Specialist > ARRL Asst. Director, NW Division, Technical Resources > >> On 9/13/20 3:57 PM, Dick Dievendorff wrote: >> When unpowered the KAT500 is bypassed, ANT1. >> >> When the ATU is in mode BYP, yes, it?s bypassed. >> >> 73 de Dick, K6KR >> >>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >>> >>> ?Hello, >>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is a single feedline to a 6BTV, and an analyzer says all is good at low power. At 100 watts, all seems good. >>> >>> All other bands seem OK at high power. >>> >>> Question: When in bypass, is the entire tuner bypassed? >>> Question: When turned off is the tuner bypassed? Which antenna is default? >>> -- >>> 73, and thanks, >>> Dave (NK7Z) >>> https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] > > > ------------------------------ > > Message: 12 > Date: Sun, 13 Sep 2020 17:54:02 -0700 > From: Dave Cole <[hidden email]> > To: Ken Winterling <[hidden email]>, Dick Dievendorff > <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Thanks Ken... That is the next step... Now I need to locate one... > > 73, and thanks, > Dave (NK7Z) > https://www.nk7z.net > ARRL Volunteer Examiner > ARRL Technical Specialist > ARRL Asst. Director, NW Division, Technical Resources > >> On 9/13/20 4:24 PM, Ken Winterling wrote: >> When you have issues like this the best test is to use a known good >> dummy load. That removes the antenna system from the equation. See what >> happens on 18mHz when transmitting into the summy load. >> >> Ken >> WA2LBI >> >> >> >> >> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >> <mailto:[hidden email]>> wrote: >> >> When unpowered the KAT500 is bypassed, ANT1. >> >> When the ATU is in mode BYP, yes, it?s bypassed. >> >> 73 de Dick, K6KR >> >>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >> <mailto:[hidden email]>> wrote: >>> >>> ?Hello, >>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >> only. Antenna is a single feedline to a 6BTV, and an analyzer says >> all is good at low power.? At 100 watts, all seems good. >>> >>> All other bands seem OK at high power. >>> >>> Question:? When in bypass, is the entire tuner bypassed? >>> Question:? When turned off is the tuner bypassed?? Which antenna >> is default? >>> -- >>> 73, and thanks, >>> Dave (NK7Z) >>> https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >> <mailto:[hidden email]> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] <mailto:[hidden email]> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] <mailto:[hidden email]> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] <mailto:[hidden email]> >> > > > ------------------------------ > > Message: 13 > Date: Sun, 13 Sep 2020 18:50:41 -0700 > From: David Gilbert <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > > I don't know where you got the idea that the K-Line produces the > cleanest signals.? As several people have pointed out, because of the 12 > volt finals the transmit IMD performance of the existing K-line is > relatively poor. > > Dave?? AB7E > > >> On 9/13/2020 2:32 PM, JR wrote: >> Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest >> transmit signals around.?? Do we need predistortion ?? If so, why, and >> how much better is it than what we already have?? Should I wait to buy >> a new rig until that is available? >> >> Thanks and Happy Trails to all.?? K8JHR > > > > ------------------------------ > > Message: 14 > Date: Sun, 13 Sep 2020 21:59:13 -0400 > From: Bill Frantz <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: > <[hidden email]> > > Content-Type: text/plain; charset=UTF-8; format=flowed > > Wayne is right, it's the right thing to do. And we amateurs try > to produce the best signals we can. (Ignore the wide CW signals > during contests. :-) ) > > But the value will also show up during multi-op situations like > running 14A during field day. Field day is much more fun if > everyone gets a chance to operate. > > 73 Bill AE6JV > > >> On 9/13/20 at 6:03 PM, [hidden email] (Wayne Burdick) wrote: >> >> Predistortion, correctly applied, can reduce interference >> between adjacent stations on a crowded band. This is a factor >> at least some fraction of the time during typical amateur radio >> use. Beyond that, the motivation for a ?pure? signal >> exemplifies the amateur spirit of cooperation, and is an >> example of keeping the hobby on the forefront of electrical design. > > ----------------------------------------------------------------------- > Bill Frantz | Privacy is dead, get over | Periwinkle > (408)348-7900 | it. | 150 Rivermead > Rd #235 > www.pwpconsult.com | - Scott McNealy (1999) | Peterborough, > NH 03458 > > > > ------------------------------ > > Message: 15 > Date: Sun, 13 Sep 2020 19:14:52 -0700 > From: Wayne Burdick <[hidden email]> > To: David Gilbert <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=us-ascii > > 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. > > On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. > > 73, > Wayne > N6KR > > > >> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >> >> >> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >> >> Dave AB7E >> >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > > ------------------------------ > > Message: 16 > Date: Sun, 13 Sep 2020 21:14:47 -0700 > From: Jim Brown <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: > <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > >> On 9/13/2020 2:32 PM, JR wrote: >> The Elecraft K-Line already produces some of the cleanest, purest >> transmit signals around.?? Do we need predistortion ? > > If you care about a clean signal, YES! If you don't mind being a bad > neighbor, no. > > 73, Jim K9YC > > > ------------------------------ > > Message: 17 > Date: Sun, 13 Sep 2020 21:25:46 -0700 > From: Jim Brown <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: > <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > >> On 9/13/2020 3:03 PM, Wayne Burdick wrote: >> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. > > I hope that this feature will be implemented for CW as well. CW is 100% > AM of a carrier by rectangular pulses, so any distortion in the transmit > chain results in clicks. Elecraft pioneered very clean keying waveforms; > it would be unfortunate for that to be lost with IMD in the power stages. > > 73, Jim K9YC > > > ------------------------------ > > Message: 18 > Date: Sun, 13 Sep 2020 21:43:21 -0700 > From: David Gilbert <[hidden email]> > To: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > > > Of course, but that's a conscious choice by Elecraft and it does not > result in the "cleanest, purest signals around."? I give Elecraft tons > of credit for the other measures they have take to produce good signals, > which is why I own and will keep my upgraded K3 probably forever, but > K8JHR simply was incorrect in his comment and it makes a difference when > considering the expanding focus by folks like Sherwood and others to > clean up the bands.? When it comes to IMD, Elecraft is not one of the > better players.? The fact that that's by choice doesn't change > anything.? I suspect that 95+% of K3 rigs are used in portable/emergency > situations less than 5% of the time. > > 73, > Dave?? AB7E > > > >> On 9/13/2020 7:14 PM, Wayne Burdick wrote: >> 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. >> >> On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. >> >> 73, >> Wayne >> N6KR >> >> >> >>>> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >>> >>> >>> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >>> >>> Dave AB7E >>> >>> >>> On 9/13/2020 2:32 PM, JR wrote: >>>> Why are so many ops obsessed with predistortion? >>>> >>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>> >>>> Thanks and Happy Trails to all. K8JHR >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] > > > > ------------------------------ > > Message: 19 > Date: Sun, 13 Sep 2020 21:51:33 -0700 > From: kevinr <[hidden email]> > To: Elecraft Reflector <[hidden email]> > Subject: [Elecraft] Elecraft CW Net Report > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Good Evening, > > ?? Signals were stronger than last week with less noise on both bands.? > QSB was a little higher on forty meters.? Most of you reported very nice > weather.? Even out west the weather is not too bad once you allow for > all the smoke.? It certainly makes working outside difficult.? Staying > inside helps but I still have a stuffy nose and a mild headache.? My > begonias don't like the smoke either, they are rapidly losing blossoms. > > ?? The forty meter net improves as the days grow shorter.? I was able > to reach Texas again.? Hopefully there will be some new sunspots this > week.? That would help my reach. > > > ? On 14050.8 kHz at 2200z: > > W0CZ - Ken - ND > > NO8V - John - MI > > AB9V - Mike - IN > > K6XK - Roy - IA > > > ? On 7047.5 kHz at 0045z: > > W0CZ - Ken - ND > > K0DTJ - Brian - CA > > K6PJV - Dale - CA > > W8OV - Dave - TX > > > I plan to work inside again this week.? I need to collect wood but > exercise in these smoky conditions makes the headaches worse. A week of > rain starting tomorrow night will help.? Maybe they will slow the fires > in the Cascades and clear our skies.? 2020 has been quite a year.? I'm > waiting for January so we can start over. > > ?? Until next week 73, > > ????? Kevin.? KD5ONS > > > - > > > > cutting angle = degrees(atan2(twist, PI() * caliber)) > > > > ------------------------------ > > Message: 20 > Date: Mon, 14 Sep 2020 04:52:03 -0700 > From: Dave Cole <[hidden email]> > To: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Hi ken, > Added the dummy, no problems, so it is the antenna... Also, given it is > a 6BTV with the 18 meter add on, and all other bands work, it is not the > feedline... > > This makes it simple to fix! It is either a break with the laws of > physics as we understand them today-- or a connection has come loose. > Given there are only two connections... I suspect it will be a simple fix. > > 73, and thanks, > Dave (NK7Z) > https://www.nk7z.net > ARRL Volunteer Examiner > ARRL Technical Specialist > ARRL Asst. Director, NW Division, Technical Resources > >> On 9/13/20 4:24 PM, Ken Winterling wrote: >> When you have issues like this the best test is to use a known good >> dummy load. That removes the antenna system from the equation. See what >> happens on 18mHz when transmitting into the summy load. >> >> Ken >> WA2LBI >> >> >> >> >> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >> <mailto:[hidden email]>> wrote: >> >> When unpowered the KAT500 is bypassed, ANT1. >> >> When the ATU is in mode BYP, yes, it?s bypassed. >> >> 73 de Dick, K6KR >> >>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >> <mailto:[hidden email]>> wrote: >>> >>> ?Hello, >>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >> only. Antenna is a single feedline to a 6BTV, and an analyzer says >> all is good at low power.? At 100 watts, all seems good. >>> >>> All other bands seem OK at high power. >>> >>> Question:? When in bypass, is the entire tuner bypassed? >>> Question:? When turned off is the tuner bypassed?? Which antenna >> is default? >>> -- >>> 73, and thanks, >>> Dave (NK7Z) >>> https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >> <mailto:[hidden email]> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] <mailto:[hidden email]> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] <mailto:[hidden email]> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] <mailto:[hidden email]> >> > > > ------------------------------ > > Message: 21 > Date: Mon, 14 Sep 2020 07:54:32 -0400 > From: Ken Winterling <[hidden email]> > To: Dave Cole <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good > antenna on 18 MHz. > Message-ID: > <[hidden email]> > Content-Type: text/plain; charset="UTF-8" > > GL! > > Ken > WA2LBI > > > > > >> On Mon, Sep 14, 2020 at 7:53 AM Dave Cole <[hidden email]> wrote: >> >> Hi ken, >> Added the dummy, no problems, so it is the antenna... Also, given it is >> a 6BTV with the 18 meter add on, and all other bands work, it is not the >> feedline... >> >> This makes it simple to fix! It is either a break with the laws of >> physics as we understand them today-- or a connection has come loose. >> Given there are only two connections... I suspect it will be a simple fix. >> >> 73, and thanks, >> Dave (NK7Z) >> https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> >>> On 9/13/20 4:24 PM, Ken Winterling wrote: >>> When you have issues like this the best test is to use a known good >>> dummy load. That removes the antenna system from the equation. See what >>> happens on 18mHz when transmitting into the summy load. >>> >>> Ken >>> WA2LBI >>> >>> >>> >>> >>> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >>> <mailto:[hidden email]>> wrote: >>> >>> When unpowered the KAT500 is bypassed, ANT1. >>> >>> When the ATU is in mode BYP, yes, it?s bypassed. >>> >>> 73 de Dick, K6KR >>> >>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >>> <mailto:[hidden email]>> wrote: >>>> >>>> ?Hello, >>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >>> only. Antenna is a single feedline to a 6BTV, and an analyzer says >>> all is good at low power. At 100 watts, all seems good. >>>> >>>> All other bands seem OK at high power. >>>> >>>> Question: When in bypass, is the entire tuner bypassed? >>>> Question: When turned off is the tuner bypassed? Which antenna >>> is default? >>>> -- >>>> 73, and thanks, >>>> Dave (NK7Z) >>>> https://www.nk7z.net >>>> ARRL Volunteer Examiner >>>> ARRL Technical Specialist >>>> ARRL Asst. Director, NW Division, Technical Resources >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>> <mailto:[hidden email]> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: >> http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] <mailto:[hidden email]> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] <mailto: >> [hidden email]> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] <mailto:[hidden email]> >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ------------------------------ > > Message: 22 > Date: Mon, 14 Sep 2020 08:10:55 -0700 > From: Nigel Lemaire <[hidden email]> > To: [hidden email] > Subject: [Elecraft] 630 meter operation on the K4 > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > Wondering what capabilities the K4 will have on this (these) bands... > > 73 > Nigel > Wa6MSE > > > ------------------------------ > > Message: 23 > Date: Sun, 13 Sep 2020 22:42:02 -0400 > From: "Charlie T" <[hidden email]> > To: <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <007401d68a40$a4157ce0$ec4076a0$@erols.com> > Content-Type: text/plain; charset="UTF-8" > > According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB signal on the air of any commercial amateur radio transmitters. > > 73, Charlie k3ICH > > > > > -----Original Message----- > From: [hidden email] <[hidden email]> On Behalf Of David Gilbert > Sent: Sunday, September 13, 2020 9:51 PM > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > > > I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. > > Dave AB7E > > >> On 9/13/2020 2:32 PM, JR wrote: >> Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest >> transmit signals around. Do we need predistortion ? If so, why, and >> how much better is it than what we already have? Should I wait to buy >> a new rig until that is available? >> >> Thanks and Happy Trails to all. K8JHR > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] > > > > ------------------------------ > > Message: 24 > Date: Mon, 14 Sep 2020 07:29:48 -0400 > From: "Charlie T" <[hidden email]> > To: <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <001601d68a8a$5e2f81e0$1a8e85a0$@erols.com> > Content-Type: text/plain; charset="UTF-8" > > Maybe I'm missing something here, but it would seem to me that if an FET linear amplifier running from 50 V or higher is considerably cleaner than one running from 12 V, that, for a high end rig, a simple step-up switching supply could solve the problem. But, that obviously adds to the cost so it IS somewhat of a conundrum. > > However, implementing the pre-distortion function IS probably a better long-term solution. > > 73, Charlie k3ICH > > > > > -----Original Message----- > From: [hidden email] <[hidden email]> On Behalf Of David Gilbert > Sent: Monday, September 14, 2020 12:43 AM > To: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > > > > Of course, but that's a conscious choice by Elecraft and it does not result in the "cleanest, purest signals around." I give Elecraft tons of credit for the other measures they have take to produce good signals, which is why I own and will keep my upgraded K3 probably forever, but K8JHR simply was incorrect in his comment and it makes a difference when considering the expanding focus by folks like Sherwood and others to clean up the bands. When it comes to IMD, Elecraft is not one of the better players. The fact that that's by choice doesn't change anything. I suspect that 95+% of K3 rigs are used in portable/emergency situations less than 5% of the time. > > 73, > Dave AB7E > > > >> On 9/13/2020 7:14 PM, Wayne Burdick wrote: >> 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. >> >> On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. >> >> 73, >> Wayne >> N6KR >> >> >> >>>> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >>> >>> >>> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >>> >>> Dave AB7E >>> >>> >>> On 9/13/2020 2:32 PM, JR wrote: >>>> Why are so many ops obsessed with predistortion? >>>> >>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>> >>>> Thanks and Happy Trails to all. K8JHR >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net Please help support this >>> email list: http://www.qsl.net/donate.html Message delivered to >>> [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] > > > > ------------------------------ > > Message: 25 > Date: Mon, 14 Sep 2020 11:00:25 -0500 > From: "Dr. William J. Schmidt" <[hidden email]> > To: "'Elecraft List'" <[hidden email]> > Subject: Re: [Elecraft] Why predistortion ? > Message-ID: <000c01d68ab0$2937ac80$7ba70580$@wjschmidt.com> > Content-Type: text/plain; charset="iso-8859-1" > > 6AU6 - 6CL6 - 6146A trio is a very and associated circuitry produces some of > the lowest distortion products when run at the right conditions (voltages, > etc). Note at 75 watts the 6146 is in its sweet spot. > > > Dr. William J. Schmidt - K9HZ > > > email:? [hidden email] > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Charlie T > Sent: Sunday, September 13, 2020 9:42 PM > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > > According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB > signal on the air of any commercial amateur radio transmitters. > > 73, Charlie k3ICH > > > > > -----Original Message----- > From: [hidden email] <[hidden email]> On > Behalf Of David Gilbert > Sent: Sunday, September 13, 2020 9:51 PM > To: [hidden email] > Subject: Re: [Elecraft] Why predistortion ? > > > I don't know where you got the idea that the K-Line produces the cleanest > signals. As several people have pointed out, because of the 12 volt finals > the transmit IMD performance of the existing K-line is relatively poor. > > Dave AB7E > > >> On 9/13/2020 2:32 PM, JR wrote: >> Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest >> transmit signals around. Do we need predistortion ? If so, why, and >> how much better is it than what we already have? Should I wait to buy >> a new rig until that is available? >> >> Thanks and Happy Trails to all. K8JHR > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message > delivered to [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Message > delivered to [hidden email] > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > > > ------------------------------ > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > http://mailman.qth.net/mailman/listinfo/elecraft > You must be a subscriber to post. > Elecraft web page: http://www.elecraft.com > > End of Elecraft Digest, Vol 197, Issue 18 > ***************************************** Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Elecraft Digest, Vol 197, Issue 18
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For goodness sake, please trim your posts!!! ;-(
73, Alan. G4GNX ------ Original Message ------ From: [hidden email] To: [hidden email] Sent: 14/09/2020 21:10:47 Subject: Re: [Elecraft] Elecraft Digest, Vol 197, Issue 18 > > >Sent from my iPhone > >> On Sep 14, 2020, at 11:03 AM, [hidden email] wrote: >> >> Send Elecraft mailing list submissions to >>[hidden email] >> >> To subscribe or unsubscribe via the World Wide Web, visit >>http://mailman.qth.net/mailman/listinfo/elecraft >> or, via email, send a message with subject or body 'help' to >>[hidden email] >> >> You can reach the person managing the list at >>[hidden email] >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of Elecraft digest..." >> >> >> Today's Topics: >> >> 1. Why predistortion ? (JR) >> 2. Re: Why predistortion ? (Wayne Burdick) >> 3. Re: Why predistortion ? (E.H. Russell) >> 4. Re: Why predistortion ? (Randy Farmer) >> 5. KAT500: Fails to tune, and shows 3:1 on good antenna on 18 >> MHz. (Dave Cole) >> 6. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Dick Dievendorff) >> 7. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Ken Winterling) >> 8. Why predistortion ? (John Harper) >> 9. Re: Why predistortion ? (Wes) >> 10. Re: Why predistortion ? (W2xj) >> 11. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Dave Cole) >> 12. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Dave Cole) >> 13. Re: Why predistortion ? (David Gilbert) >> 14. Re: Why predistortion ? (Bill Frantz) >> 15. Re: Why predistortion ? (Wayne Burdick) >> 16. Re: Why predistortion ? (Jim Brown) >> 17. Re: Why predistortion ? (Jim Brown) >> 18. Re: Why predistortion ? (David Gilbert) >> 19. Elecraft CW Net Report (kevinr) >> 20. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Dave Cole) >> 21. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on >> 18 MHz. (Ken Winterling) >> 22. 630 meter operation on the K4 (Nigel Lemaire) >> 23. Re: Why predistortion ? (Charlie T) >> 24. Re: Why predistortion ? (Charlie T) >> 25. Re: Why predistortion ? (Dr. William J. Schmidt) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Sun, 13 Sep 2020 17:32:21 -0400 >> From: JR <[hidden email]> >> To: [hidden email] >> Subject: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Why are so many ops obsessed with predistortion? >> >> The Elecraft K-Line already produces some of the cleanest, purest >> transmit signals around.?? Do we need predistortion ?? If so, why, and >> how much better is it than what we already have?? Should I wait to buy a >> new rig until that is available? >> >> Thanks and Happy Trails to all.?? K8JHR >> _________________________________ >> >> >> ------------------------------ >> >> Message: 2 >> Date: Sun, 13 Sep 2020 15:03:00 -0700 >> From: Wayne Burdick <[hidden email]> >> To: JR <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >> Hi JR, >> >> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >> >> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >> >> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >> >> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >> >> Wayne, >> N6KR >> >> ---- >> elecraft.com >> >>> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >>> >>> ?Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >>> _________________________________ >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> ------------------------------ >> >> Message: 3 >> Date: Sun, 13 Sep 2020 18:41:52 -0400 >> From: "E.H. Russell" <[hidden email]> >> To: "'Wayne Burdick'" <[hidden email]>, "'JR'" >> <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <006301d68a1f$13ca1b80$3b5e5280$@qrv.com> >> Content-Type: text/plain; charset="utf-8" >> >> Well put. >> >> TKS, >> 73 ED W2RF >> >> >> >> >> -----Original Message----- >> From: [hidden email] <[hidden email]> On Behalf Of Wayne Burdick >> Sent: Sunday, September 13, 2020 6:03 PM >> To: JR <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> >> Hi JR, >> >> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >> >> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >> >> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >> >> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >> >> Wayne, >> N6KR >> >> ---- >> elecraft.com >> >>> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >>> >>> ?Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >>> _________________________________ >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net Please help support this email >>> list: http://www.qsl.net/donate.html Message delivered to >>>[hidden email] >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 4 >> Date: Sun, 13 Sep 2020 18:48:17 -0400 >> From: Randy Farmer <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> I can testify to the effectiveness of predistortion techniques from my 5 >> years or so as a CDMA Cellular Base Station engineer with Motorola. The >> first generation of CDMA transmitters had a very specific "spectral >> mask" that had to be certified. As I recall, the transmitter output that >> met the Spectral Mask requirements of something like -60 dBc outside of >> the channel bandwidth showed up with essentially vertical sides (and a >> very flat top) on a spectrum analyzer. Obtaining this performance was >> neither cheap nor easy, and the associated testing was pretty stringent >> as well. Meeting the specs demanded very sophisticated predistortion >> techniques. Be glad that conventional SSB and the fairly simple >> waveforms used in amateur digital comms don't require too much dynamic >> headroom. The first generation CDMA waveform had a roughly 10:1, or 20dB >> peak-to-average power ratio. This meant that the transmitters we >> designed to produce 20W average power were actually capable of 200W >> continuous output power and still met the spectral mask IMD >> requirements. Putting multiple carriers through the PA required either >> higher power capability or derating the power output for each individual >> carrier. I no longer work in the industry, so I don't know what the >> current generation of signals requires, but with the greater bandwidths >> and more complex modulation schemes used now you can bet the >> requirements, and therefore the transmitter design challenge, didn't get >> any easier. >> >> 73... >> Randy, W8FN >> >>> On 9/13/2020 6:03 PM, Wayne Burdick wrote: >>> Hi JR, >>> >>> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >>> >>> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >>> >>> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >>> >>> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >>> >>> Wayne, >>> N6KR >>> >>> ---- >>> elecraft.com >> >> >> ------------------------------ >> >> Message: 5 >> Date: Sun, 13 Sep 2020 15:48:40 -0700 >> From: Dave Cole <[hidden email]> >> To: [hidden email] >> Subject: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Hello, >> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. >> Antenna is a single feedline to a 6BTV, and an analyzer says all is good >> at low power. At 100 watts, all seems good. >> >> All other bands seem OK at high power. >> >> Question: When in bypass, is the entire tuner bypassed? >> Question: When turned off is the tuner bypassed? Which antenna is default? >> -- >> 73, and thanks, >> Dave (NK7Z) >>https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> >> >> ------------------------------ >> >> Message: 6 >> Date: Sun, 13 Sep 2020 15:57:03 -0700 >> From: Dick Dievendorff <[hidden email]> >> To: Dave Cole <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >> When unpowered the KAT500 is bypassed, ANT1. >> >> When the ATU is in mode BYP, yes, it?s bypassed. >> >> 73 de Dick, K6KR >> >>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >>> >>> ?Hello, >>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is a single feedline to a 6BTV, and an analyzer says all is good at low power. At 100 watts, all seems good. >>> >>> All other bands seem OK at high power. >>> >>> Question: When in bypass, is the entire tuner bypassed? >>> Question: When turned off is the tuner bypassed? Which antenna is default? >>> -- >>> 73, and thanks, >>> Dave (NK7Z) >>>https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> ------------------------------ >> >> Message: 7 >> Date: Sun, 13 Sep 2020 19:24:24 -0400 >> From: Ken Winterling <[hidden email]> >> To: Dick Dievendorff <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: >> <[hidden email]> >> Content-Type: text/plain; charset="UTF-8" >> >> When you have issues like this the best test is to use a known good dummy >> load. That removes the antenna system from the equation. See what happens >> on 18mHz when transmitting into the summy load. >> >> Ken >> WA2LBI >> >> >> >> >> >>> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email]> wrote: >>> >>> When unpowered the KAT500 is bypassed, ANT1. >>> >>> When the ATU is in mode BYP, yes, it?s bypassed. >>> >>> 73 de Dick, K6KR >>> >>>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >>>> >>>> ?Hello, >>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. >>> Antenna is a single feedline to a 6BTV, and an analyzer says all is good at >>> low power. At 100 watts, all seems good. >>>> >>>> All other bands seem OK at high power. >>>> >>>> Question: When in bypass, is the entire tuner bypassed? >>>> Question: When turned off is the tuner bypassed? Which antenna is >>> default? >>>> -- >>>> 73, and thanks, >>>> Dave (NK7Z) >>>>https://www.nk7z.net >>>> ARRL Volunteer Examiner >>>> ARRL Technical Specialist >>>> ARRL Asst. Director, NW Division, Technical Resources >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> ------------------------------ >> >> Message: 8 >> Date: Sun, 13 Sep 2020 18:40:01 -0500 >> From: John Harper <[hidden email]> >> To: Elecraft list <[hidden email]> >> Subject: [Elecraft] Why predistortion ? >> Message-ID: >> <CAPHmH=O3V_u977xn0c9qJ1hCEyxwfdVYMXXhL30QRg=[hidden email]> >> Content-Type: text/plain; charset="UTF-8" >> >> Here's a demonstration of predistortion in use (relevant part starts at the >> 10-minute point): >>https://www.youtube.com/watch?v=0adHZOTqTlQ >> >> John AE5X >>https://ae5x.blogspot.com >> >> >>> Why are so many ops obsessed with predistortion? >> >> >> ------------------------------ >> >> Message: 9 >> Date: Sun, 13 Sep 2020 17:20:39 -0700 >> From: Wes <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> You're kidding, right? >> >> Wes? N7WS >> >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> The Elecraft K-Line already produces some of the cleanest, purest transmit >>> signals around.... >>> >>> Thanks and Happy Trails to all.?? K8JHR >> >> >> >> ------------------------------ >> >> Message: 10 >> Date: Sun, 13 Sep 2020 20:24:07 -0400 >> From: W2xj <[hidden email]> >> To: Wayne Burdick <[hidden email]> >> Cc: [hidden email], JR <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >> wayne, >> >> After you have the K4 fully put to bed, for your next project you might want to consider an amp that is directly driven by an I/Q stream. The amplifier will be much more efficient (less power consumption) and you start out with less IMD before any pre-distortion. >> >> Sent from my iPad >> >>> On Sep 13, 2020, at 6:05 PM, Wayne Burdick <[hidden email]> wrote: >>> >>> ?Hi JR, >>> >>> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. Even with adequate feedback and bias, an amplifier operated in the vicinity of its 1 dB compression point (where it is most efficient) will exhibit such characteristics. >>> >>> To improve on this you either need to operate class A, which is highly inefficient, or use predistortion. >>> >>> A small number of commercial transceivers are now providing predistortion, in some cases as an optional/experimental setting (that not everyone uses, or at least not all the time). There are constraints on predistortion power range imposed by the headroom limit of the amplifier stage itself. Go over that point and distortion will be worse than without predistortion. >>> >>> Predistortion, correctly applied, can reduce interference between adjacent stations on a crowded band. This is a factor at least some fraction of the time during typical amateur radio use. Beyond that, the motivation for a ?pure? signal exemplifies the amateur spirit of cooperation, and is an example of keeping the hobby on the forefront of electrical design. >>> >>> Wayne, >>> N6KR >>> >>> ---- >>> elecraft.com >>> >>>>> On Sep 13, 2020, at 2:34 PM, JR <[hidden email]> wrote: >>>> >>>> ?Why are so many ops obsessed with predistortion? >>>> >>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>> >>>> Thanks and Happy Trails to all. K8JHR >>>> _________________________________ >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 11 >> Date: Sun, 13 Sep 2020 17:53:36 -0700 >> From: Dave Cole <[hidden email]> >> To: Dick Dievendorff <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> That helps triage the issue... Something in my antenna must have gone >> wonky... I am using a 6BTV, with the 18 Meter add on kit, so the same >> feedpoint is used for all bands, and they are fine... I was worried it >> was the tuner. I'll go check the antenna out tonight, and in the >> morning as well... THANK YOU! Knowing the tuner is bypassed in Bypass, >> helps... Next is to put a dummy load on the tuner... >> >> 73, and thanks, >> Dave (NK7Z) >>https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> >>> On 9/13/20 3:57 PM, Dick Dievendorff wrote: >>> When unpowered the KAT500 is bypassed, ANT1. >>> >>> When the ATU is in mode BYP, yes, it?s bypassed. >>> >>> 73 de Dick, K6KR >>> >>>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email]> wrote: >>>> >>>> ?Hello, >>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is a single feedline to a 6BTV, and an analyzer says all is good at low power. At 100 watts, all seems good. >>>> >>>> All other bands seem OK at high power. >>>> >>>> Question: When in bypass, is the entire tuner bypassed? >>>> Question: When turned off is the tuner bypassed? Which antenna is default? >>>> -- >>>> 73, and thanks, >>>> Dave (NK7Z) >>>>https://www.nk7z.net >>>> ARRL Volunteer Examiner >>>> ARRL Technical Specialist >>>> ARRL Asst. Director, NW Division, Technical Resources >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >> >> >> ------------------------------ >> >> Message: 12 >> Date: Sun, 13 Sep 2020 17:54:02 -0700 >> From: Dave Cole <[hidden email]> >> To: Ken Winterling <[hidden email]>, Dick Dievendorff >> <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Thanks Ken... That is the next step... Now I need to locate one... >> >> 73, and thanks, >> Dave (NK7Z) >>https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> >>> On 9/13/20 4:24 PM, Ken Winterling wrote: >>> When you have issues like this the best test is to use a known good >>> dummy load. That removes the antenna system from the equation. See what >>> happens on 18mHz when transmitting into the summy load. >>> >>> Ken >>> WA2LBI >>> >>> >>> >>> >>> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >>> <mailto:[hidden email]>> wrote: >>> >>> When unpowered the KAT500 is bypassed, ANT1. >>> >>> When the ATU is in mode BYP, yes, it?s bypassed. >>> >>> 73 de Dick, K6KR >>> >>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >>> <mailto:[hidden email]>> wrote: >>>> >>>> ?Hello, >>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >>> only. Antenna is a single feedline to a 6BTV, and an analyzer says >>> all is good at low power.? At 100 watts, all seems good. >>>> >>>> All other bands seem OK at high power. >>>> >>>> Question:? When in bypass, is the entire tuner bypassed? >>>> Question:? When turned off is the tuner bypassed?? Which antenna >>> is default? >>>> -- >>>> 73, and thanks, >>>> Dave (NK7Z) >>>>https://www.nk7z.net >>>> ARRL Volunteer Examiner >>>> ARRL Technical Specialist >>>> ARRL Asst. Director, NW Division, Technical Resources >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>> <mailto:[hidden email]> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] <mailto:[hidden email]> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] <mailto:[hidden email]> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] <mailto:[hidden email]> >>> >> >> >> ------------------------------ >> >> Message: 13 >> Date: Sun, 13 Sep 2020 18:50:41 -0700 >> From: David Gilbert <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> >> I don't know where you got the idea that the K-Line produces the >> cleanest signals.? As several people have pointed out, because of the 12 >> volt finals the transmit IMD performance of the existing K-line is >> relatively poor. >> >> Dave?? AB7E >> >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest >>> transmit signals around.?? Do we need predistortion ?? If so, why, and >>> how much better is it than what we already have?? Should I wait to buy >>> a new rig until that is available? >>> >>> Thanks and Happy Trails to all.?? K8JHR >> >> >> >> ------------------------------ >> >> Message: 14 >> Date: Sun, 13 Sep 2020 21:59:13 -0400 >> From: Bill Frantz <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: >> <[hidden email]> >> >> Content-Type: text/plain; charset=UTF-8; format=flowed >> >> Wayne is right, it's the right thing to do. And we amateurs try >> to produce the best signals we can. (Ignore the wide CW signals >> during contests. :-) ) >> >> But the value will also show up during multi-op situations like >> running 14A during field day. Field day is much more fun if >> everyone gets a chance to operate. >> >> 73 Bill AE6JV >> >> >>> On 9/13/20 at 6:03 PM, [hidden email] (Wayne Burdick) wrote: >>> >>> Predistortion, correctly applied, can reduce interference >>> between adjacent stations on a crowded band. This is a factor >>> at least some fraction of the time during typical amateur radio >>> use. Beyond that, the motivation for a ?pure? signal >>> exemplifies the amateur spirit of cooperation, and is an >>> example of keeping the hobby on the forefront of electrical design. >> >> ----------------------------------------------------------------------- >> Bill Frantz | Privacy is dead, get over | Periwinkle >> (408)348-7900 | it. | 150 Rivermead >> Rd #235 >>www.pwpconsult.com | - Scott McNealy (1999) | Peterborough, >> NH 03458 >> >> >> >> ------------------------------ >> >> Message: 15 >> Date: Sun, 13 Sep 2020 19:14:52 -0700 >> From: Wayne Burdick <[hidden email]> >> To: David Gilbert <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=us-ascii >> >> 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. >> >> On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. >> >> 73, >> Wayne >> N6KR >> >> >> >>> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >>> >>> >>> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >>> >>> Dave AB7E >>> >>> >>>> On 9/13/2020 2:32 PM, JR wrote: >>>> Why are so many ops obsessed with predistortion? >>>> >>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>> >>>> Thanks and Happy Trails to all. K8JHR >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 16 >> Date: Sun, 13 Sep 2020 21:14:47 -0700 >> From: Jim Brown <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: >> <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> The Elecraft K-Line already produces some of the cleanest, purest >>> transmit signals around.?? Do we need predistortion ? >> >> If you care about a clean signal, YES! If you don't mind being a bad >> neighbor, no. >> >> 73, Jim K9YC >> >> >> ------------------------------ >> >> Message: 17 >> Date: Sun, 13 Sep 2020 21:25:46 -0700 >> From: Jim Brown <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: >> <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >>> On 9/13/2020 3:03 PM, Wayne Burdick wrote: >>> Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD in the range of -30 dBc (ARRL method) on some HF bands. This reflects a limitation in the state of the art. >> >> I hope that this feature will be implemented for CW as well. CW is 100% >> AM of a carrier by rectangular pulses, so any distortion in the transmit >> chain results in clicks. Elecraft pioneered very clean keying waveforms; >> it would be unfortunate for that to be lost with IMD in the power stages. >> >> 73, Jim K9YC >> >> >> ------------------------------ >> >> Message: 18 >> Date: Sun, 13 Sep 2020 21:43:21 -0700 >> From: David Gilbert <[hidden email]> >> To: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> >> >> Of course, but that's a conscious choice by Elecraft and it does not >> result in the "cleanest, purest signals around."? I give Elecraft tons >> of credit for the other measures they have take to produce good signals, >> which is why I own and will keep my upgraded K3 probably forever, but >> K8JHR simply was incorrect in his comment and it makes a difference when >> considering the expanding focus by folks like Sherwood and others to >> clean up the bands.? When it comes to IMD, Elecraft is not one of the >> better players.? The fact that that's by choice doesn't change >> anything.? I suspect that 95+% of K3 rigs are used in portable/emergency >> situations less than 5% of the time. >> >> 73, >> Dave?? AB7E >> >> >> >>> On 9/13/2020 7:14 PM, Wayne Burdick wrote: >>> 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. >>> >>> On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. >>> >>> 73, >>> Wayne >>> N6KR >>> >>> >>> >>>>> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >>>> >>>> >>>> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >>>> >>>> Dave AB7E >>>> >>>> >>>> On 9/13/2020 2:32 PM, JR wrote: >>>>> Why are so many ops obsessed with predistortion? >>>>> >>>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>>> >>>>> Thanks and Happy Trails to all. K8JHR >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 19 >> Date: Sun, 13 Sep 2020 21:51:33 -0700 >> From: kevinr <[hidden email]> >> To: Elecraft Reflector <[hidden email]> >> Subject: [Elecraft] Elecraft CW Net Report >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Good Evening, >> >> ?? Signals were stronger than last week with less noise on both bands.? >> QSB was a little higher on forty meters.? Most of you reported very nice >> weather.? Even out west the weather is not too bad once you allow for >> all the smoke.? It certainly makes working outside difficult.? Staying >> inside helps but I still have a stuffy nose and a mild headache.? My >> begonias don't like the smoke either, they are rapidly losing blossoms. >> >> ?? The forty meter net improves as the days grow shorter.? I was able >> to reach Texas again.? Hopefully there will be some new sunspots this >> week.? That would help my reach. >> >> >> ? On 14050.8 kHz at 2200z: >> >> W0CZ - Ken - ND >> >> NO8V - John - MI >> >> AB9V - Mike - IN >> >> K6XK - Roy - IA >> >> >> ? On 7047.5 kHz at 0045z: >> >> W0CZ - Ken - ND >> >> K0DTJ - Brian - CA >> >> K6PJV - Dale - CA >> >> W8OV - Dave - TX >> >> >> I plan to work inside again this week.? I need to collect wood but >> exercise in these smoky conditions makes the headaches worse. A week of >> rain starting tomorrow night will help.? Maybe they will slow the fires >> in the Cascades and clear our skies.? 2020 has been quite a year.? I'm >> waiting for January so we can start over. >> >> ?? Until next week 73, >> >> ????? Kevin.? KD5ONS >> >> >> - >> >> >> >> cutting angle = degrees(atan2(twist, PI() * caliber)) >> >> >> >> ------------------------------ >> >> Message: 20 >> Date: Mon, 14 Sep 2020 04:52:03 -0700 >> From: Dave Cole <[hidden email]> >> To: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Hi ken, >> Added the dummy, no problems, so it is the antenna... Also, given it is >> a 6BTV with the 18 meter add on, and all other bands work, it is not the >> feedline... >> >> This makes it simple to fix! It is either a break with the laws of >> physics as we understand them today-- or a connection has come loose. >> Given there are only two connections... I suspect it will be a simple fix. >> >> 73, and thanks, >> Dave (NK7Z) >>https://www.nk7z.net >> ARRL Volunteer Examiner >> ARRL Technical Specialist >> ARRL Asst. Director, NW Division, Technical Resources >> >>> On 9/13/20 4:24 PM, Ken Winterling wrote: >>> When you have issues like this the best test is to use a known good >>> dummy load. That removes the antenna system from the equation. See what >>> happens on 18mHz when transmitting into the summy load. >>> >>> Ken >>> WA2LBI >>> >>> >>> >>> >>> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >>> <mailto:[hidden email]>> wrote: >>> >>> When unpowered the KAT500 is bypassed, ANT1. >>> >>> When the ATU is in mode BYP, yes, it?s bypassed. >>> >>> 73 de Dick, K6KR >>> >>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >>> <mailto:[hidden email]>> wrote: >>>> >>>> ?Hello, >>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >>> only. Antenna is a single feedline to a 6BTV, and an analyzer says >>> all is good at low power.? At 100 watts, all seems good. >>>> >>>> All other bands seem OK at high power. >>>> >>>> Question:? When in bypass, is the entire tuner bypassed? >>>> Question:? When turned off is the tuner bypassed?? Which antenna >>> is default? >>>> -- >>>> 73, and thanks, >>>> Dave (NK7Z) >>>>https://www.nk7z.net >>>> ARRL Volunteer Examiner >>>> ARRL Technical Specialist >>>> ARRL Asst. Director, NW Division, Technical Resources >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>> <mailto:[hidden email]> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] <mailto:[hidden email]> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] <mailto:[hidden email]> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] <mailto:[hidden email]> >>> >> >> >> ------------------------------ >> >> Message: 21 >> Date: Mon, 14 Sep 2020 07:54:32 -0400 >> From: Ken Winterling <[hidden email]> >> To: Dave Cole <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good >> antenna on 18 MHz. >> Message-ID: >> <[hidden email]> >> Content-Type: text/plain; charset="UTF-8" >> >> GL! >> >> Ken >> WA2LBI >> >> >> >> >> >>> On Mon, Sep 14, 2020 at 7:53 AM Dave Cole <[hidden email]> wrote: >>> >>> Hi ken, >>> Added the dummy, no problems, so it is the antenna... Also, given it is >>> a 6BTV with the 18 meter add on, and all other bands work, it is not the >>> feedline... >>> >>> This makes it simple to fix! It is either a break with the laws of >>> physics as we understand them today-- or a connection has come loose. >>> Given there are only two connections... I suspect it will be a simple fix. >>> >>> 73, and thanks, >>> Dave (NK7Z) >>>https://www.nk7z.net >>> ARRL Volunteer Examiner >>> ARRL Technical Specialist >>> ARRL Asst. Director, NW Division, Technical Resources >>> >>>> On 9/13/20 4:24 PM, Ken Winterling wrote: >>>> When you have issues like this the best test is to use a known good >>>> dummy load. That removes the antenna system from the equation. See what >>>> happens on 18mHz when transmitting into the summy load. >>>> >>>> Ken >>>> WA2LBI >>>> >>>> >>>> >>>> >>>> On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[hidden email] >>>> <mailto:[hidden email]>> wrote: >>>> >>>> When unpowered the KAT500 is bypassed, ANT1. >>>> >>>> When the ATU is in mode BYP, yes, it?s bypassed. >>>> >>>> 73 de Dick, K6KR >>>> >>>>> On Sep 13, 2020, at 15:52, Dave Cole <[hidden email] >>>> <mailto:[hidden email]>> wrote: >>>>> >>>>> ?Hello, >>>>> My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., >>>> only. Antenna is a single feedline to a 6BTV, and an analyzer says >>>> all is good at low power. At 100 watts, all seems good. >>>>> >>>>> All other bands seem OK at high power. >>>>> >>>>> Question: When in bypass, is the entire tuner bypassed? >>>>> Question: When turned off is the tuner bypassed? Which antenna >>>> is default? >>>>> -- >>>>> 73, and thanks, >>>>> Dave (NK7Z) >>>>>https://www.nk7z.net >>>>> ARRL Volunteer Examiner >>>>> ARRL Technical Specialist >>>>> ARRL Asst. Director, NW Division, Technical Resources >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[hidden email] >>>> <mailto:[hidden email]> >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: >>>http://www.qsl.net/donate.html >>>>> Message delivered to [hidden email] <mailto:[hidden email]> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] <mailto: >>>[hidden email]> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] <mailto:[hidden email]> >>>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> >> >> ------------------------------ >> >> Message: 22 >> Date: Mon, 14 Sep 2020 08:10:55 -0700 >> From: Nigel Lemaire <[hidden email]> >> To: [hidden email] >> Subject: [Elecraft] 630 meter operation on the K4 >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Wondering what capabilities the K4 will have on this (these) bands... >> >> 73 >> Nigel >> Wa6MSE >> >> >> ------------------------------ >> >> Message: 23 >> Date: Sun, 13 Sep 2020 22:42:02 -0400 >> From: "Charlie T" <[hidden email]> >> To: <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <007401d68a40$a4157ce0$ec4076a0$@erols.com> >> Content-Type: text/plain; charset="UTF-8" >> >> According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB signal on the air of any commercial amateur radio transmitters. >> >> 73, Charlie k3ICH >> >> >> >> >> -----Original Message----- >> From: [hidden email] <[hidden email]> On Behalf Of David Gilbert >> Sent: Sunday, September 13, 2020 9:51 PM >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> >> >> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >> >> Dave AB7E >> >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest >>> transmit signals around. Do we need predistortion ? If so, why, and >>> how much better is it than what we already have? Should I wait to buy >>> a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 24 >> Date: Mon, 14 Sep 2020 07:29:48 -0400 >> From: "Charlie T" <[hidden email]> >> To: <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <001601d68a8a$5e2f81e0$1a8e85a0$@erols.com> >> Content-Type: text/plain; charset="UTF-8" >> >> Maybe I'm missing something here, but it would seem to me that if an FET linear amplifier running from 50 V or higher is considerably cleaner than one running from 12 V, that, for a high end rig, a simple step-up switching supply could solve the problem. But, that obviously adds to the cost so it IS somewhat of a conundrum. >> >> However, implementing the pre-distortion function IS probably a better long-term solution. >> >> 73, Charlie k3ICH >> >> >> >> >> -----Original Message----- >> From: [hidden email] <[hidden email]> On Behalf Of David Gilbert >> Sent: Monday, September 14, 2020 12:43 AM >> To: Elecraft Reflector <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> >> >> >> Of course, but that's a conscious choice by Elecraft and it does not result in the "cleanest, purest signals around." I give Elecraft tons of credit for the other measures they have take to produce good signals, which is why I own and will keep my upgraded K3 probably forever, but K8JHR simply was incorrect in his comment and it makes a difference when considering the expanding focus by folks like Sherwood and others to clean up the bands. When it comes to IMD, Elecraft is not one of the better players. The fact that that's by choice doesn't change anything. I suspect that 95+% of K3 rigs are used in portable/emergency situations less than 5% of the time. >> >> 73, >> Dave AB7E >> >> >> >>> On 9/13/2020 7:14 PM, Wayne Burdick wrote: >>> 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other manufacturers, we accept this constraint so the equipment can be used in a wide variety of portable/emergency power situations. As a result we have IMD numbers in exactly the same range as other products that are subject to this constraint. >>> >>> On the other hand, our transceivers are best in class in terms of transmitted keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was thinking of. >>> >>> 73, >>> Wayne >>> N6KR >>> >>> >>> >>>>> On Sep 13, 2020, at 6:50 PM, David Gilbert <[hidden email]> wrote: >>>> >>>> >>>> I don't know where you got the idea that the K-Line produces the cleanest signals. As several people have pointed out, because of the 12 volt finals the transmit IMD performance of the existing K-line is relatively poor. >>>> >>>> Dave AB7E >>>> >>>> >>>> On 9/13/2020 2:32 PM, JR wrote: >>>>> Why are so many ops obsessed with predistortion? >>>>> >>>>> The Elecraft K-Line already produces some of the cleanest, purest transmit signals around. Do we need predistortion ? If so, why, and how much better is it than what we already have? Should I wait to buy a new rig until that is available? >>>>> >>>>> Thanks and Happy Trails to all. K8JHR >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net Please help support this >>>> email list: http://www.qsl.net/donate.html Message delivered to >>>>[hidden email] >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] >> >> >> >> ------------------------------ >> >> Message: 25 >> Date: Mon, 14 Sep 2020 11:00:25 -0500 >> From: "Dr. William J. Schmidt" <[hidden email]> >> To: "'Elecraft List'" <[hidden email]> >> Subject: Re: [Elecraft] Why predistortion ? >> Message-ID: <000c01d68ab0$2937ac80$7ba70580$@wjschmidt.com> >> Content-Type: text/plain; charset="iso-8859-1" >> >> 6AU6 - 6CL6 - 6146A trio is a very and associated circuitry produces some of >> the lowest distortion products when run at the right conditions (voltages, >> etc). Note at 75 watts the 6146 is in its sweet spot. >> >> >> Dr. William J. Schmidt - K9HZ >> >> >> email:? [hidden email] >> >> >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of Charlie T >> Sent: Sunday, September 13, 2020 9:42 PM >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> >> According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB >> signal on the air of any commercial amateur radio transmitters. >> >> 73, Charlie k3ICH >> >> >> >> >> -----Original Message----- >> From: [hidden email] <[hidden email]> On >> Behalf Of David Gilbert >> Sent: Sunday, September 13, 2020 9:51 PM >> To: [hidden email] >> Subject: Re: [Elecraft] Why predistortion ? >> >> >> I don't know where you got the idea that the K-Line produces the cleanest >> signals. As several people have pointed out, because of the 12 volt finals >> the transmit IMD performance of the existing K-line is relatively poor. >> >> Dave AB7E >> >> >>> On 9/13/2020 2:32 PM, JR wrote: >>> Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest >>> transmit signals around. Do we need predistortion ? If so, why, and >>> how much better is it than what we already have? Should I wait to buy >>> a new rig until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html Message >> delivered to [hidden email] >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html Message >> delivered to [hidden email] >> >> >> -- >> This email has been checked for viruses by AVG. >>https://www.avg.com >> >> >> >> ------------------------------ >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >>http://mailman.qth.net/mailman/listinfo/elecraft >> You must be a subscriber to post. >> Elecraft web page: http://www.elecraft.com >> >> End of Elecraft Digest, Vol 197, Issue 18 >> ***************************************** >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:[hidden email] > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html >Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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