[KX3] equalization in DATA-A mode?
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[KX3] equalization in DATA-A mode?
 
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My KX3 is connected to my computer through a SignaLink USB device.
I only operate digital modes, either with fldigi or wsjt-x, and always in DATA-A mode. The waterfall display in both these programs shows a pronounced increase in levels at the low and high ends of the audio passband. So much so that the background noise goes into "yellow", or even "red". A picture of this is at http://imgurl.org?di=5S2I That was taken with no antenna connected at all, VFO at 14070, in DATA-A mode. Bandwidth was set to 4kHz. The radio has the ATU and roofing filter options installed. Since DATA-A is supposed to disable all equalization and compression, I thought at first that the SignaLink was introducing this, but if I use the PBT knob to descrease the bandwidth to 2 kHz, the "yellow" regions move toward the center - though the effect is most pronounced whan the BW is 4kHz. This makes me think it is an artifact of the DSP algorithms. If I change the mode to SSB so I can re-enable RX EQ, I can dial-down the ends a bit. Also notice that outside of the silent region just outside the chosen bandwidth, the noise level rises again. This is not generally a problem so far. Is this expected behavior? It makes it difficult to see signals that fall toward the ends of the passband. In extreme cases I retune the VFO to make them fall in the center. ______________________________________________________________ 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: [KX3] equalization in DATA-A mode?
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On Sun,8/30/2015 2:31 PM, Paul Dickson wrote:
> A picture of this is athttp://imgurl.org?di=5S2I First, turn off "Flatten," which will get rid of the yellow and red peaks at either end. Second, set Start to 250 or 300 Hz and Bins/Pixels to 4 or 5, so that the display shows only the bandwidth of your IF (in this plot, audio from 350 Hz to 3.55 kHz). Audio frequencies outside these limits don't get through your IF and roofing filters, so don't waste DSP on them. These comments apply specifically to WSJT-X, but the same concepts are at play in FLDIGI (which I don't use, so can't help you with). 73, Jim K9YC ______________________________________________________________ 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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On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it.
Thanks in advance. Jerry Moore AE4PB, Future K3S owner – 5 days and a wakeup. http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. ______________________________________________________________ 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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In reply to this post by Jim Brown-10
On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it.
Thanks in advance. Jerry Moore AE4PB, Future K3S owner – 5 days and a wakeup. http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. ______________________________________________________________ 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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Did you happen to notice that the IMD test that KA4WJA is basing his
thread on is from 2008? Do you think that Elecraft might have made some improvements to the K3 since then? 73, Scott N9AA On 8/30/15 10:14 PM, [hidden email] wrote: > On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it. > > > > Thanks in advance. > > Jerry Moore > > AE4PB, Future K3S owner – 5 days and a wakeup. > > > > http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. > > > > ______________________________________________________________ > 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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In reply to this post by ae4pb
Jerry
I understand the k3 in question was a very early version and Rob consulted with zelecraft and that issue was fixed long ago. -----Original Message----- From: "[hidden email]" <[hidden email]> Sent: 31/08/2015 12:16 PM To: "[hidden email]" <[hidden email]> Subject: [Elecraft] K3S IMD Questions On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it. Thanks in advance. Jerry Moore AE4PB, Future K3S owner – 5 days and a wakeup. http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. ______________________________________________________________ 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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In reply to this post by Scott Manthe-2
Scott,
I think the report might be a year old. I don't place much stock in eHam, most articles are Perception ' based and I prefer Rob's testing and reports. Wayne acknowledged the IMD issue way back when Rob pointed it out, it was fixed very quickly. Gary -----Original Message----- From: "Scott Manthe" <[hidden email]> Sent: 31/08/2015 12:26 PM To: "[hidden email]" <[hidden email]>; "[hidden email]" <[hidden email]> Subject: Re: [Elecraft] K3S IMD Questions Did you happen to notice that the IMD test that KA4WJA is basing his thread on is from 2008? Do you think that Elecraft might have made some improvements to the K3 since then? 73, Scott N9AA On 8/30/15 10:14 PM, [hidden email] wrote: > On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it. > > > > Thanks in advance. > > Jerry Moore > > AE4PB, Future K3S owner – 5 days and a wakeup. > > > > http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. > > > > ______________________________________________________________ > 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] ______________________________________________________________ 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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In as much as most multi contest stations use K3 radios and will likely
move to K3S radios, there wouldn't seem to be any concerns in this regard. 73 Bob, K4TAX K3S s/n 10,163 On 8/30/2015 9:33 PM, Gary wrote: > Scott, > > I think the report might be a year old. > > I don't place much stock in eHam, most articles are Perception ' based and I prefer Rob's testing and reports. > > Wayne acknowledged the IMD issue way back when Rob pointed it out, it was fixed very quickly. > Gary > > -----Original Message----- > From: "Scott Manthe" <[hidden email]> > Sent: 31/08/2015 12:26 PM > To: "[hidden email]" <[hidden email]>; "[hidden email]" <[hidden email]> > Subject: Re: [Elecraft] K3S IMD Questions > > Did you happen to notice that the IMD test that KA4WJA is basing his > thread on is from 2008? Do you think that Elecraft might have made some > improvements to the K3 since then? > > 73, > Scott N9AA > > > On 8/30/15 10:14 PM, [hidden email] wrote: >> On eham.com someone was pointing out that the K3 has (perhaps had) IMD issues compared to some others. I’m not an expert but would like to know if this has been fixed? It seems there are less expensive radios with better IMD. I’m still pretty much sold on the K3S but would like to know more about this and if it’s an issue. What the implications are of the increased IMD, and what if anything I can do resolve it. >> >> >> >> Thanks in advance. >> >> Jerry Moore >> >> AE4PB, Future K3S owner – 5 days and a wakeup. >> >> >> >> http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is the thread. >> >> >> >> ______________________________________________________________ >> 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] > ______________________________________________________________ > 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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In reply to this post by Gary Gregory-2
Thanks guys, I expected that was the case, but, didn't know what to say when the guy was saying those things about the k3. I really can't wait until Saturday gets here. I'm looking forward to getting my hands on the rig and getting my kit ordered.
On August 30, 2015 10:33:07 PM EDT, Gary <[hidden email]> wrote: >Scott, > >I think the report might be a year old. > >I don't place much stock in eHam, most articles are Perception ' based >and I prefer Rob's testing and reports. > >Wayne acknowledged the IMD issue way back when Rob pointed it out, it >was fixed very quickly. >Gary > >-----Original Message----- >From: "Scott Manthe" <[hidden email]> >Sent: 31/08/2015 12:26 PM >To: "[hidden email]" <[hidden email]>; >"[hidden email]" <[hidden email]> >Subject: Re: [Elecraft] K3S IMD Questions > >Did you happen to notice that the IMD test that KA4WJA is basing his >thread on is from 2008? Do you think that Elecraft might have made some > >improvements to the K3 since then? > >73, >Scott N9AA > > >On 8/30/15 10:14 PM, [hidden email] wrote: >> On eham.com someone was pointing out that the K3 has (perhaps had) >IMD issues compared to some others. I’m not an expert but would like to >know if this has been fixed? It seems there are less expensive radios >with better IMD. I’m still pretty much sold on the K3S but would like >to know more about this and if it’s an issue. What the implications are >of the increased IMD, and what if anything I can do resolve it. >> >> >> >> Thanks in advance. >> >> Jerry Moore >> >> AE4PB, Future K3S owner – 5 days and a wakeup. >> >> >> >> http://www.eham.net/ehamforum/smf/index.php/topic,97093.0.html is >the thread. >> >> >> >> ______________________________________________________________ >> 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] >______________________________________________________________ >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] -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ______________________________________________________________ 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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In reply to this post by Bob McGraw - K4TAX
Again, the Sherwood TX IMD test that is the basis of the eHam thread is
almost 7 years old. That problem was fixed long ago, which is why so many multi-multi stations and DXpeditions have been using K3s (not K3S's) for all of these years. There hasn't really been any concern about the K3's TX IMD for quite sometime, except for the occasional eHam troll. 73, Scott N9AA On 8/30/15 11:09 PM, Bob McGraw - K4TAX wrote: > In as much as most multi contest stations use K3 radios and will > likely move to K3S radios, there wouldn't seem to be any concerns in > this regard. > > 73 > Bob, K4TAX > K3S s/n 10,163 > > On 8/30/2015 9:33 PM, Gary wrote: >> Scott, >> >> I think the report might be a year old. >> >> I don't place much stock in eHam, most articles are Perception ' >> based and I prefer Rob's testing and reports. >> >> Wayne acknowledged the IMD issue way back when Rob pointed it out, it >> was fixed very quickly. >> Gary >> >> -----Original Message----- >> From: "Scott Manthe" <[hidden email]> >> Sent: 31/08/2015 12:26 PM >> To: "[hidden email]" <[hidden email]>; >> "[hidden email]" <[hidden email]> >> Subject: Re: [Elecraft] K3S IMD Questions >> >> Did you happen to notice that the IMD test that KA4WJA is basing his >> thread on is from 2008? Do you think that Elecraft might have made some >> improvements to the K3 since then? >> >> 73, >> Scott N9AA >> >> ______________________________________________________________ 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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Some time ago I was discussing this with one of the locals who maintained
that the K3 had terrible TX IMD. I wonder if there are any newer published TX IMD test results? In any case I guess the K3S has better TX IMD due to the new PA design. 73, Yngvi TF3Y On Mon, Aug 31, 2015 at 3:22 AM, Scott Manthe <[hidden email]> wrote: > Again, the Sherwood TX IMD test that is the basis of the eHam thread is > almost 7 years old. That problem was fixed long ago, which is why so many > multi-multi stations and DXpeditions have been using K3s (not K3S's) for > all of these years. There hasn't really been any concern about the K3's TX > IMD for quite sometime, except for the occasional eHam troll. > > 73, > Scott N9AA > > > On 8/30/15 11:09 PM, Bob McGraw - K4TAX wrote: > >> In as much as most multi contest stations use K3 radios and will likely >> move to K3S radios, there wouldn't seem to be any concerns in this regard. >> >> 73 >> Bob, K4TAX >> K3S s/n 10,163 >> >> On 8/30/2015 9:33 PM, Gary wrote: >> >>> Scott, >>> >>> I think the report might be a year old. >>> >>> I don't place much stock in eHam, most articles are Perception ' based >>> and I prefer Rob's testing and reports. >>> >>> Wayne acknowledged the IMD issue way back when Rob pointed it out, it >>> was fixed very quickly. >>> Gary >>> >>> -----Original Message----- >>> From: "Scott Manthe" <[hidden email]> >>> Sent: 31/08/2015 12:26 PM >>> To: "[hidden email]" <[hidden email]>; " >>> [hidden email]" <[hidden email]> >>> Subject: Re: [Elecraft] K3S IMD Questions >>> >>> Did you happen to notice that the IMD test that KA4WJA is basing his >>> thread on is from 2008? Do you think that Elecraft might have made some >>> improvements to the K3 since then? >>> >>> 73, >>> Scott N9AA >>> >>> >>> > ______________________________________________________________ > 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] > -- http://www.tf3y.net ______________________________________________________________ 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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In reply to this post by Scott Manthe-2
On Sun,8/30/2015 8:22 PM, Scott Manthe wrote:
> Again, the Sherwood TX IMD test that is the basis of the eHam thread > is almost 7 years old. Study k9yc.com/TXNoise.pdf which is a comparison of ARRL LAb testing of popular transceivers, including the K3. Occupied bandwidth of a CW signal is an excellent test of IMD, because CW is 100% modulation of a carrier by a square wave, whose infinite harmonics excite IMD. The K3 is the cleanest of all rigs tested, and it isn't close. IMD in a K3 is highest at its highest power setting, and is also highest with low DC power supply voltage. Unlike many other popular rigs, IMD in the K3 gets even better at reduced output power. Most of the better power amps require drive power in the range of 30-50 watts, and having a clean signal matters most when you're loud in the other guy's RX. :) 73, Jim K9YC ______________________________________________________________ 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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Thanks Jim.
I forgot to mention that I was aware of your survey in terms of CW signal purity. Even though I'm personally most interested in CW I wonder if there is any recent two tone SSB tests that's been published? 73, Yngvi TF3Y On Mon, Aug 31, 2015 at 4:32 PM, Jim Brown <[hidden email]> wrote: > On Sun,8/30/2015 8:22 PM, Scott Manthe wrote: > >> Again, the Sherwood TX IMD test that is the basis of the eHam thread is >> almost 7 years old. >> > > Study k9yc.com/TXNoise.pdf which is a comparison of ARRL LAb testing of > popular transceivers, including the K3. Occupied bandwidth of a CW signal > is an excellent test of IMD, because CW is 100% modulation of a carrier by > a square wave, whose infinite harmonics excite IMD. The K3 is the cleanest > of all rigs tested, and it isn't close. > > IMD in a K3 is highest at its highest power setting, and is also highest > with low DC power supply voltage. Unlike many other popular rigs, IMD in > the K3 gets even better at reduced output power. Most of the better power > amps require drive power in the range of 30-50 watts, and having a clean > signal matters most when you're loud in the other guy's RX. :) > > 73, Jim K9YC > > ______________________________________________________________ > 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] > -- http://www.tf3y.net ______________________________________________________________ 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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In reply to this post by ae4pb
Jim, et al:
"...having a clean signal matters most when you're loud in the other guy's RX." From your mouth to God's ears! I was pleasantly surprised at the lack of "turn the knobs all the way to the right" entrants in this past weekend's SSB Sprint! Yes, few mushy and bassy signals, but the large majority of the signals I heard here were very clear, punchy and easy to copy! I don't note this in other phone contests recently. Seems that the majority of the players in this Sprint thing are the more successful contest types, from the callsigns represented. Could they know something that the general run of the mill guys know about articulated and clean audio? How can this be evangelized better? There is hope for SSB contests yet! Lu-W4LT K-Line ______________________________________________________________ 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: [KX3] equalization in DATA-A mode?
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In reply to this post by Paul Dickson
That seems to have been it! The doc says that the Flatten button makes
it correct for un-eveness in the passband. I am guessing that WSJT sees the tapering ends of the spectrum where the KX3 signal drops off (where ever I happen to have the bandwidth set) and over-corrects for it. - Paul KB1EHD On 08/30/2015 06:29 PM, David Anderson wrote: > Have you tried un-checking the flatten button? I read that causes such > problems. I use WSJT 10 here with my KX3 on DATA A at full bandwidth > which isn't 4kHz ( but that is another question) and it is reasonably > flat. 73 David Anderson GM4JJJ ______________________________________________________________ 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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In reply to this post by Yngvi (TF3Y)
On Mon,8/31/2015 10:04 AM, Yngvi (TF3Y) wrote:
> Even though I'm personally most interested in CW I wonder if there is > any recent two tone SSB tests that's been published? I've published some SSB bandwidth measurements using pink noise as excitation. Because pink noise contains all frequencies, the spectra resembles music and speech, and is dynamic, it excites IMD in a manner comparable to speech. http://k9yc.com/P3_Spectrum_Measurements.pdf http://k9yc.com/FTDX5000_Report.pdf So far, I've measured only a few rigs using pink noise, but of those I've measured, I've seen very little difference between them. On the air is a very different story -- it's VERY common to see distortion on SSB signals in the form of both upper and lower sidebands on audio peaks. Because it is present in both sidebands, I strongly suspect it's caused by power amps that are over-driven, or poorly tuned, or improperly biased. We hear it as splatter (sometimes as wide as 10-20 kHz), and see it on the P3 and horizontal lines corresponding to audio peaks. 73, Jim K9YC ______________________________________________________________ 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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Thank you Jim,
I'd expect if my signal was being overdriven that someone would tell me so I could fix it *shrug*. Anyway... I think this has been covered pretty well. Thanks for all the responses. Jer -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Jim Brown Sent: Monday, August 31, 2015 11:14 PM Cc: [hidden email] Subject: Re: [Elecraft] K3S IMD Questions On Mon,8/31/2015 10:04 AM, Yngvi (TF3Y) wrote: > Even though I'm personally most interested in CW I wonder if there is > any recent two tone SSB tests that's been published? I've published some SSB bandwidth measurements using pink noise as excitation. Because pink noise contains all frequencies, the spectra resembles music and speech, and is dynamic, it excites IMD in a manner comparable to speech. http://k9yc.com/P3_Spectrum_Measurements.pdf http://k9yc.com/FTDX5000_Report.pdf So far, I've measured only a few rigs using pink noise, but of those I've measured, I've seen very little difference between them. On the air is a very different story -- it's VERY common to see distortion on SSB signals in the form of both upper and lower sidebands on audio peaks. Because it is present in both sidebands, I strongly suspect it's caused by power amps that are over-driven, or poorly tuned, or improperly biased. We hear it as splatter (sometimes as wide as 10-20 kHz), and see it on the P3 and horizontal lines corresponding to audio peaks. 73, Jim K9YC ______________________________________________________________ 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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In reply to this post by Jim Brown-10
Thanks Jim.
This is COOL. 73, Yngvi TF3Y On Tue, Sep 1, 2015 at 3:13 AM, Jim Brown <[hidden email]> wrote: > On Mon,8/31/2015 10:04 AM, Yngvi (TF3Y) wrote: > >> Even though I'm personally most interested in CW I wonder if there is any >> recent two tone SSB tests that's been published? >> > > I've published some SSB bandwidth measurements using pink noise as > excitation. Because pink noise contains all frequencies, the spectra > resembles music and speech, and is dynamic, it excites IMD in a manner > comparable to speech. > > http://k9yc.com/P3_Spectrum_Measurements.pdf > > http://k9yc.com/FTDX5000_Report.pdf > > So far, I've measured only a few rigs using pink noise, but of those I've > measured, I've seen very little difference between them. > > On the air is a very different story -- it's VERY common to see distortion > on SSB signals in the form of both upper and lower sidebands on audio > peaks. Because it is present in both sidebands, I strongly suspect it's > caused by power amps that are over-driven, or poorly tuned, or improperly > biased. We hear it as splatter (sometimes as wide as 10-20 kHz), and see it > on the P3 and horizontal lines corresponding to audio peaks. > > > 73, Jim K9YC > > > ______________________________________________________________ > 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] > -- http://www.tf3y.net ______________________________________________________________ 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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In reply to this post by Jim Brown-10
Could someone who fully understands Transmitter specs/imd..etc help me out a
bit off reflector (don't to bore folks). The thread on eham is http://www.eham.net/ehamforum/smf/index.php/topic,104725.60.html I have no idea what the guy is talking about. As far as I can tell there's no issue but I honestly don't know enough about the subject. All help and education is appreciated. Jerry Moore AE4PB, Future K3S, 4 days and a wakeup. ______________________________________________________________ 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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In reply to this post by ae4pb
I have been playing with a Flex 6300 here in my shack recently. I consider it a great piece of test equipment for analyzing signals in the shack as well as on the air. It does everything and more, as a spectrum analyzer, that my old HP141 analog setup did, except it doesn't have a tracking generator.
My measurements are not completed and I am still experimenting, but here is what I've done so far. Phase noise, cw transmitted bandwidth, and 2 tone IMD tests. My two rigs are a K3/100 and an FT100D (how good, and how bad can you get!) Using a Flex 6300 as a spectrum analyzer, I fed a greatly attenuated signal into it, keeping the level just under 0 dbm, and assuming it is not generating imd of its own, but I haven't quantified that yet. Phase noise tests - I was interested in seeing if it could display the RELATIVE benefit of the new synthesizer on my K3, looking at phase noise. Here are PRELIMINARY RELATIVE results, without numbers, in order of phase noise level at 2 khz separation:An 8640B signal generator (known to have low phase noise)The K3 with original synthesizerThe FT100 After I install the new synthesizer I hope to be able to compare it to the original one. I verified the FFT spectrum analyzer (Flex 6300) can give an instant view of transmitted bandwith of the cw signal sending fast dots. MUCH easier and better than the old analog HP spectrum analyzer which had to sweep extremely slowly across the band with a narrow filter. With this setup you hold the key closed, and hit the control-print screen buttons on the keyboard and you have a beautiful picture ! Ain't technology great? 2-tone IMD measurements -The two tone test of the K3 showed something interesting, since it has both 10 watt and a 100 watt PAs installed. Starting with low power and cranking up the power control, you notice, of course, that the ten watt PA has worse IMD just before the big PA kicks in, in the 11-12 watt range. Then it is very clean (approximately -40 db for third order) at its best, and ok in the 30 watt range (where it would be set to run my 8877 amp) but then gets quite ugly above 65 watts. And I mean in the -20 db range at 100 watts. IF it was overloading the spectrum analyzer these tests would be invalid, so I need to verify that. As I said these tests are preliminary. I need a few more hours. In my humble opinion, running at full power, 100 watts barefoot, my K3 would be transmitting an unacceptably sloppy signal. Keeping it in the 65 watt range or under, or driving an amp would be better, provided your amp is clean. My 8877 amp is VERY clean. I don't know about a solid state amp. Some of the ugliest signals I have seen on the bands with the Flex panadapter in very limited observations have come from Expert 1500 watt amps (2 examples). The very best was an Anan 100 with a Ten Tec 1500 watt tube amp. The waterfall was a brick wall - NOTHING whatsoever outside the 3 khz bandwidth. Rick K2XT ______________________________________________________________ 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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