K3 in a cw pileup - needs work
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Yes.
For non-portable use how about a "K3 Pro" or "K3 MK V++" that clips a few circuit traces and has a daughter board that uses two or three filter slots to house a stout IF amp, an H-mode second mixer and a PIN attenuator before the DSP? The one remaining filter would only have to be good enough to get rid of the image. Just thinking out loud. --- On Sat, 2/6/10, Geoffrey Mackenzie-Kennedy <[hidden email]> wrote: Hi Guy, The problem reported has the classic characteristics of in-passband IMD caused by a small dynamic range (IMDDR3) IF system, rather than being something caused by the AGC sub-system. Yes changing the AGC's loop characteristics will alter the effect, but the root cause is still non-linearity in the signal path. I suspect the second mixer. Trouble is that large IMDDR3 IF systems can consume a lot of power, and low power drain by the K3's receiver was a design goal I believe. 73, Geoff GM4ESD ______________________________________________________________ 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 |
Re: Firmware upload problem
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In reply to this post by W4CCS
> I'm using the Microham router software to talk to the K3 and this has > been working great until now. DO NOT use microHAM Router to upload firmware to the K3. It IS NOT SUPPORTED. Find a computer with a hardware serial port or a dumb external USB to serial converter. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of W4CCS > Sent: Saturday, February 06, 2010 11:15 AM > To: [hidden email] > Subject: [Elecraft] Firmware upload problem > > > Attempted to upload new firmware to the K3 this morning and > got the "MCU > LD" error. Now the K3 is basically dumb. In the manual, it says to > unplug the power for 5 seconds, Hold the power button for > approximately > 10 seconds and then re-load the firmware. > > My problem is that I can no longer get the computer to talk to the K3 > and therefore cannot attempt a re-load. > > I'm using the Microham router software to talk to the K3 and this has > been working great until now. > > Question, does the K3 keep the old settings (38400, 8, N, 1) > or does it > resort back to the default settings which are ?? > > I also tried a direct cable (straight and null modem) and > cannot get any > communication to occur. > > > I'm stuck until I get the K3 talking to the computer again.. > > HELP..!! > > de W4CCS > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
Re: Firmware upload problem
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You can use microHAM, but you have to select:
No radio and dissable router queries in the microHAM software. El 06/02/2010 21:21, Joe Subich, W4TV escribió: > > >> I'm using the Microham router software to talk to the K3 and this has >> been working great until now. > > DO NOT use microHAM Router to upload firmware to the K3. > It IS NOT SUPPORTED. Find a computer with a hardware > serial port or a dumb external USB to serial converter. > > 73, > > ... Joe, W4TV > > > > >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of W4CCS >> Sent: Saturday, February 06, 2010 11:15 AM >> To: [hidden email] >> Subject: [Elecraft] Firmware upload problem >> >> >> Attempted to upload new firmware to the K3 this morning and >> got the "MCU >> LD" error. Now the K3 is basically dumb. In the manual, it says to >> unplug the power for 5 seconds, Hold the power button for >> approximately >> 10 seconds and then re-load the firmware. >> >> My problem is that I can no longer get the computer to talk to the K3 >> and therefore cannot attempt a re-load. >> >> I'm using the Microham router software to talk to the K3 and this has >> been working great until now. >> >> Question, does the K3 keep the old settings (38400, 8, N, 1) >> or does it >> resort back to the default settings which are ?? >> >> I also tried a direct cable (straight and null modem) and >> cannot get any >> communication to occur. >> >> >> I'm stuck until I get the K3 talking to the computer again.. >> >> HELP..!! >> >> de W4CCS >> ______________________________________________________________ >> 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 > > ______________________________________________________________ > 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 -- Rubén Navarro Huedo - EA5BZ http://www.palotes.com ______________________________________________________________ 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 |
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My opinion --
Since Joe W4TV is an authority on microHAM gear, I would say "use it at your own peril" if you insist. Yes, there have been reports of success, but Joe says IT IS NOT SUPPORTED! Please do not complain that you broke your K3 with a firmware load when you used the microHAM router., just get a good serial port (preferably hardware), follow the steps in the K3Utility help file and do a proper reload. 73, Don W3FPR Ruben Navarro Huedo wrote: > You can use microHAM, but you have to select: > No radio and dissable router queries in the microHAM software. > > > El 06/02/2010 21:21, Joe Subich, W4TV escribió: > >> >>> I'm using the Microham router software to talk to the K3 and this has >>> been working great until now. >>> >> DO NOT use microHAM Router to upload firmware to the K3. >> It IS NOT SUPPORTED. Find a computer with a hardware >> serial port or a dumb external USB to serial converter. >> >> 73, >> >> ... Joe, W4TV >> >> >> >> >> >>> -----Original Message----- >>> From: [hidden email] >>> [mailto:[hidden email]] On Behalf Of W4CCS >>> Sent: Saturday, February 06, 2010 11:15 AM >>> To: [hidden email] >>> Subject: [Elecraft] Firmware upload problem >>> >>> >>> Attempted to upload new firmware to the K3 this morning and >>> got the "MCU >>> LD" error. Now the K3 is basically dumb. In the manual, it says to >>> unplug the power for 5 seconds, Hold the power button for >>> approximately >>> 10 seconds and then re-load the firmware. >>> >>> My problem is that I can no longer get the computer to talk to the K3 >>> and therefore cannot attempt a re-load. >>> >>> I'm using the Microham router software to talk to the K3 and this has >>> been working great until now. >>> >>> Question, does the K3 keep the old settings (38400, 8, N, 1) >>> or does it >>> resort back to the default settings which are ?? >>> >>> I also tried a direct cable (straight and null modem) and >>> cannot get any >>> communication to occur. >>> >>> >>> I'm stuck until I get the K3 talking to the computer again.. >>> >>> HELP..!! >>> >>> de W4CCS >>> ______________________________________________________________ >>> 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 >>> >> ______________________________________________________________ >> 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 >> > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.733 / Virus Database: 271.1.1/2671 - Release Date: 02/06/10 02:35:00 > > 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 |
Re: Firmware upload problem
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In reply to this post by Ruben Navarro Huedo-2
Setting "No radio" does not guarantee transparent operation by microHAM Router. Again: DO NOT PERFORM A FIRMWARE UPLOAD USING MICROHAM ROUTER WITH ANY MICROHAM INTERFACE. NO EXCEPTIONS. Even though I know my way around Router and the microHAM interfaces well enough to generally make sure Router is transparent, there is no way to force and lock the data rate between the microHAM interface and the transceiver. I keep a serial cable attached to a serial port on one of my computers specifically for use when updating K3 firmware. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Ruben > Navarro Huedo > Sent: Saturday, February 06, 2010 3:26 PM > To: [hidden email] > Subject: Re: [Elecraft] Firmware upload problem > > > You can use microHAM, but you have to select: > No radio and dissable router queries in the microHAM software. > > > El 06/02/2010 21:21, Joe Subich, W4TV escribió: > > > > > >> I'm using the Microham router software to talk to the K3 > and this has > >> been working great until now. > > > > DO NOT use microHAM Router to upload firmware to the K3. > > It IS NOT SUPPORTED. Find a computer with a hardware serial port or > > a dumb external USB to serial converter. > > > > 73, > > > > ... Joe, W4TV > > > > > > > > > >> -----Original Message----- > >> From: [hidden email] > >> [mailto:[hidden email]] On Behalf Of W4CCS > >> Sent: Saturday, February 06, 2010 11:15 AM > >> To: [hidden email] > >> Subject: [Elecraft] Firmware upload problem > >> > >> > >> Attempted to upload new firmware to the K3 this morning > and got the > >> "MCU LD" error. Now the K3 is basically dumb. In the > manual, it says > >> to unplug the power for 5 seconds, Hold the power button for > >> approximately 10 seconds and then re-load the firmware. > >> > >> My problem is that I can no longer get the computer to > talk to the K3 > >> and therefore cannot attempt a re-load. > >> > >> I'm using the Microham router software to talk to the K3 > and this has > >> been working great until now. > >> > >> Question, does the K3 keep the old settings (38400, 8, N, > 1) or does > >> it resort back to the default settings which are ?? > >> > >> I also tried a direct cable (straight and null modem) and > cannot get > >> any communication to occur. > >> > >> > >> I'm stuck until I get the K3 talking to the computer again.. > >> > >> HELP..!! > >> > >> de W4CCS > >> ______________________________________________________________ > >> 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 > > > > ______________________________________________________________ > > 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 > > -- > Rubén Navarro Huedo - EA5BZ > http://www.palotes.com > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by Dave Hachadorian
You need to maximize your rf/af dynamic range - that is what is going to turn that mush into a beautiful symphony of distinct signals of varying levels. What has worked well for me is AGC off (although AGC on works fine as well), high isolation headphones, and the gain throttling techniques (most important) described by K3NA, W4ZV, myself, and others. 73, Barry N1EU (http://n1eu.com) |
Re: K3 in a cw pileup - needs work
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Just to continue from previous post - I experienced only mush in pileup reception until fully adopting this technique. High isolation headphones are critical because you want to set gain such that weak signals are lightly heard but clearly copiable. You're maximizing the receive dynamic range delivered to your ears and the high isolation means you can clearly hear fainter signals without turning up the gain and squashing the dynamic range (and too frequently engaging AF Limiter with AGC Off). 73, Barry N1EU |
Re: K3 Loses RX Audio at BW of 2.8 kHz
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In reply to this post by Scott Prather-2
My K3 was working fine last time I used it. Tonight I turned it on and
noticed a similar problem -- no audio in USB or LSB modes whenever I set the width to 3.00 kHz or less. Tried downgrading from 3.76 to 3.63 but no change. Checked all filter settings in the config menu, nothing out of place. All other modes were fine. On a hunch, I restored my last configuration backup file. It worked! Everything seems to be behaving well again. 73 de WW2PT On Feb 6, 2010, at 12:45 AM, Scott Prather wrote: > All: This evening when running FW 3.76 I'm seeing a problem with my > K3 that > I've never seen before. > > When the K3 is in the LSB, USB or AM mode, adjusting the bandwidth > down to > 2.8 kHz will result in total loss of audio, even though the S-meter > continues to read incoming signal strength. I've tried an EE-Init and > reloaded the configuration, but the problem remains. Thinking this > might be > related to 3.76, I went back to 3.30 and I have exactly the same > problem. If > I turn on the sub receiver and change its BW using BSET, it loses > LSB, USB > and AM audio at 2.8 kHz as well. To get audio to return, all I need > to do is > change the BW to 2.9 kHz or greater on either the main or the sub. > > Looking through the reflector postings, it looks like someone saw > something > similar to this in the DATA mode a few months back, and pressing the > A/B key > would clear it. However, in my case the only way I can restore audio > is to > change the BW to 2.9 kHz or greater. In the CW and DATA modes, the > audio > does not drop out at any bandwidth setting. > > Does anyone have a suggestion as to what might be going on? 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by Barry N1EU
Barry, Sorry but what do you mean by 'high isolation headphones'. Would
the Heil Pro-Set Plus do? 73 Doug EI2CN -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Barry N1EU Sent: 07 February 2010 01:01 To: [hidden email] Subject: Re: [Elecraft] K3 in a cw pileup - needs work Barry N1EU wrote: > > You need to maximize your rf/af dynamic range - that is what is going to > turn that mush into a beautiful symphony of distinct signals of varying > levels. What has worked well for me is AGC off (although AGC on works > fine as well), high isolation headphones, and the gain throttling > techniques (most important) described by K3NA, W4ZV, myself, and others. > Just to continue from previous post - I experienced only mush in pileup reception until fully adopting this technique. High isolation headphones are critical because you want to set gain such that weak signals are lightly heard but clearly copiable. You're maximizing the receive dynamic range delivered to your ears and the high isolation means you can clearly hear fainter signals without turning up the gain and squashing the dynamic range (and too frequently engaging AF Limiter with AGC Off). 73, Barry N1EU -- View this message in context: http://n2.nabble.com/K3-in-a-cw-pileup-needs-work-tp4523884p4527626.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ 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 ______________________________________________________________ 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 |
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"High isolation headphones" below means ~30 dB isolation from ambient noise. Heil does not make any in this range and most active noise reduction headphones (e.g. Bose) only have 10-15 dB. Here are some examples of what Barry meant:
http://www.extremeheadphones.com/ex-29.html http://www.sennheiserusa.com/private_headphones_dj-headphones_004974 http://www.etymotic.com/ephp/er6.aspx These are all available in the $75-100 range. 73, Bill
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Re: K3 in a cw pileup - needs work
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In reply to this post by Doug Turnbull
I'm only familiar with the Pro Set and that really doesn't have the level of isolation needed, as Bill said. I researched what drummers are using during live/recording sessions and ended up buying Sennheiser HD-280 phones, which work well. A bit more isolation could be had with in-ear phones or perhaps active isolation phones but the HD-280's are a significant step beyond the Pro Set. 73, Barry N1EU |
Re: K3 in a cw pileup - needs work
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In reply to this post by Geoffrey Mackenzie-Kennedy
Are you guys sure this is a frequency domain problem?
Has anyone measured those IMD products under the mentioned conditions and concluded from the results that they are the culprit for the mushy (somewhat vague description) audio that makes impossible to copy the different callsigns? Some W6s measured in a lab test setup a similar effect on the FT1000MP years ago and found that the problem was the AGC recovering too fast (in between symbols) making all signals sound as loud as others. The solution was to increase the time constant. The loudest signal would then set the radio gain level. Then characters in-between from weaker signals sounded weaker making them distinct (or maybe buried). I cant think why you would ever need a recovery time constant any shorter than say 150 ms, while shorter time constants are normally used -reading Clifton I think the FAST setting in the K3 is 73 ms-. At 60 WPM, a dit is 20ms long if I am not mistaken, and an intersymbols spacing (7 time units) to full gain recovery seems the shortest time that would be necessary for the receiver to recover full gain. 73 de Juan EA5RS -----Mensaje original----- De: [hidden email] [mailto:[hidden email]] En nombre de Geoffrey Mackenzie-Kennedy Enviado el: sábado, 06 de febrero de 2010 11:56 Para: Guy Olinger K2AV CC: Elecraft Discussion List Asunto: Re: [Elecraft] K3 in a cw pileup - needs work Hi Guy, The problem reported has the classic characteristics of in-passband IMD caused by a small dynamic range (IMDDR3) IF system, rather than being something caused by the AGC sub-system. Yes changing the AGC's loop characteristics will alter the effect, but the root cause is still non-linearity in the signal path. I suspect the second mixer. Trouble is that large IMDDR3 IF systems can consume a lot of power, and low power drain by the K3's receiver was a design goal I believe. 73, Geoff GM4ESD On Saturday, February 06, 2010 at 5:17 AM, Guy Olinger K2AV wrote: > Hi Dave, > > Using slope 000 is likely most of your problem. With that setting all > signals regardless of strength are set to the same level regardless of > how loud they are coming in. If they are zero beat or close, it will > mush the dickens out of the copy by making them all the same level in > your ear. I set AGC SLP to 15 for contests. I also use slow AGC the > entire time. If there are key clicks, I use NB with IF off and dsp to > t3-7 or t2-7. It rounds off CW bauds some but does not make them > uncopyable. > > Make sure your ATT/PRE/RFGAIN use conforms to something like: > > 160m ATT plus RF gain at 2 oclock > 80m ATT plus RF gain at 3 oclock > 40m ATT plus RF gain fully clockwise. > 20m " " > 15m off plus RF gain fully clockwise. > 10m PRE plus RF gain fully clockwise. > 6m " " > > ...if you are listening on your transmit antenna. At least to start. > Make sure the ambient noise on the band is moderately low audio > listening on a clear frequency. > > Using the NB with those settings, including the ATT/PRE/RFGAIN > settings. Just today I was listening to an S4 Cuban underneath what > were S9/5 key clicks with the NB off. Offending station up 500 Hz at > 30 over 9 (really), and was using 250 filter running at WIDTH 350. > > Good luck in Sprint this weekend! > > 73, Guy. ______________________________________________________________ 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 __________ Informacisn de NOD32, revisisn 4576 (20091105) __________ Este mensaje ha sido analizado con NOD32 antivirus system http://www.nod32.com ______________________________________________________________ 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by Barry N1EU
High isolation earphones:
A low cost solution is to use any in-ear type earphone that suits you plus a pair of common or garden ear defenders. The earphone lead should be as thin as possible so that the leakage around the lead as it exits the defender is as small as possible. Ear defenders I have come across make the head sweat and therefore uncomfortable after an hour or so; a cloth cover, such as aircraft headphones have is a solution, but reduces isolation slightly. David G3UNA > > > Doug Turnbull wrote: >> >> Barry, Sorry but what do you mean by 'high isolation headphones'. Would >> the Heil Pro-Set Plus do? >> > > I'm only familiar with the Pro Set and that really doesn't have the level > of > isolation needed, as Bill said. I researched what drummers are using > during > live/recording sessions and ended up buying Sennheiser HD-280 phones, > which > work well. A bit more isolation could be had with in-ear phones or > perhaps > active isolation phones but the HD-280's are a significant step beyond the > Pro Set. > > 73, > Barry N1EU > > -- ______________________________________________________________ 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by Bill W4ZV
The High isolation headphones are of course only going to help if you
have much ambient noise in the shack. I find my Beyerdynamic DT234PRO headset very good. It's not a very high isolation headset but it's a fully closed design and my shack is reasonably quiet the DT234PRO is a headset that is produced for language lab type applications and widely used by PC gamers too, it's comfortable to wear for long periods of time and provides reasonable isolation from the surroundings. I get great audio reports from the microphone which is a back electoret condenser with a cardioid pattern. It has a presence peak (like most microphones intended for the spoken word, Heil did not 'invent' this..) and the cardioid pattern helps to reduce pick-up of any ambient noise It's completely Plug and play with the K3, plug it in the back and turn Microphone bias. I paid about 60 Euro for it on Ebay 73 Brendan EI6IZ On Sun, 2010-02-07 at 03:21 -0800, Bill W4ZV wrote: > "High isolation headphones" below means ~30 dB isolation from ambient noise. > Heil does not make any in this range and most active noise reduction > headphones (e.g. Bose) only have 10-15 dB. Here are some examples of what > Barry meant: > > http://www.extremeheadphones.com/ex-29.html > http://www.sennheiserusa.com/private_headphones_dj-headphones_004974 > http://www.etymotic.com/ephp/er6.aspx > > These are all available in the $75-100 range. > > 73, Bill > > > Doug Turnbull wrote: > > > > Barry, Sorry but what do you mean by 'high isolation headphones'. Would > > the Heil Pro-Set Plus do? > > 73 Doug EI2CN > > > > -----Original Message----- > > From: [hidden email] > > [mailto:[hidden email]] On Behalf Of Barry N1EU > > Sent: 07 February 2010 01:01 > > To: [hidden email] > > Subject: Re: [Elecraft] K3 in a cw pileup - needs work > > > > > > > > Barry N1EU wrote: > >> > >> You need to maximize your rf/af dynamic range - that is what is going to > >> turn that mush into a beautiful symphony of distinct signals of varying > >> levels. What has worked well for me is AGC off (although AGC on works > >> fine as well), high isolation headphones, and the gain throttling > >> techniques (most important) described by K3NA, W4ZV, myself, and others. > >> > > Just to continue from previous post - I experienced only mush in pileup > > reception until fully adopting this technique. High isolation headphones > > are critical because you want to set gain such that weak signals are > > lightly > > heard but clearly copiable. You're maximizing the receive dynamic range > > delivered to your ears and the high isolation means you can clearly hear > > fainter signals without turning up the gain and squashing the dynamic > > range > > (and too frequently engaging AF Limiter with AGC Off). > > > > 73, > > Barry N1EU > > > > -- > > View this message in context: > > http://n2.nabble.com/K3-in-a-cw-pileup-needs-work-tp4523884p4527626.html > > Sent from the Elecraft mailing list archive at Nabble.com. > > ______________________________________________________________ > > 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 > > > > > > ______________________________________________________________ > > 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 > > > > > -- 73 Brendan EI6IZ ______________________________________________________________ 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by wc1m
If gain were throttled (e.g., via ATT on, PRE off, reduced RF Gain), wouldn't AGC Threshold be effectively raised? 73, Barry N1EU |
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This is true, but seems to be a VERY hard point to get across. Running
excess gain in RF/IF strip is at the root of some number of complaints. 73, Guy. On Sun, Feb 7, 2010 at 8:22 AM, Barry N1EU <[hidden email]> wrote: > > > Dick Green WC1M-2 wrote: >> >> Dave indicates that the problem occurred when the pileup consisted of four >> or five loud stations. This leads me to wonder if the cause is the K3 >> hardware AGC threshold being too low, even after the mod introduced two >> years ago. >> > > If gain were throttled (e.g., via ATT on, PRE off, reduced RF Gain), > wouldn't AGC Threshold be effectively raised? > > 73, > Barry N1EU > > -- > View this message in context: http://n2.nabble.com/K3-in-a-cw-pileup-needs-work-tp4523884p4529079.html > Sent from the [K3] mailing list archive at Nabble.com. > ______________________________________________________________ > 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 > 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 |
Re: K3 in a cw pileup - needs work
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If you simply raise AGC Threshold, you will have to lower AF Gain or risk overly loud audio from stronger signals. So what you would effectively be doing is translating upwards the K3's dynamic range into higher rf levels. This is NOT good practice - you want to keep the dynamic range operating at lower rf levels (thus all the talk of gain throttling).
73, Barry N1EU
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Re: K3 in a cw pileup - needs work
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Barry,
I do not believe that is true, and the graphs at http://www.cliftonlaboratories.com/elecraft_k3_agc_and_s-meter.htm#AGC_SLP_and_AGC_THR bear the real facts as well. Raising the AGC Threshold allows stronger weak signals (less than -100 dBm for THR=008) NOT to activate the AGC. Stronger signals will still activate AGC. The Hardware AGC is not changed by the threshold setting. The result is the range over which the AGC operates, and that is different than the dynamic range of the receiver. The Gain Throttling talk has mostly been with reference to the amplification of atmospheric noise rather than the detection of weak signals. While related, I do not think they are the same. The preamp and attenuator DO translate the receiver dynamic range to a higher or lower level - and the hardware AGC trigger point is translated as well. Since the RF Gain is really an IF gain, it does not alter the onset of hardware AGC. Lyle would have to comment on whether the DSP AGC is developed before or after the IF gain is applied, I do not know. 73, Don W3FPR Barry N1EU wrote: > If you simply raise AGC Threshold, you will have to lower AF Gain or risk > overly loud audio from stronger signals. So what you would effectively be > doing is translating upwards the K3's dynamic range into higher rf levels. > This is NOT good practice - you want to keep the dynamic range operating at > lower rf levels (thus all the talk of gain throttling). > > 73, > Barry N1EU > > 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 |
Re: K3 in a cw pileup - needs work
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In reply to this post by Juan EA5RS
Hello Juan,
Thanks for your e-mail. I will reply in full after I return home this evening, off-list if my answer is long. The symptoms, and the cures suggested, strongly suggest that it is a well known type of IMD problem caused by the IF hardware - which includes the roofing filter. I understand the AGC recovery problem that you mention, but do you know if the in-passband IMD products of the FT1000MP were actually measured? To measure IMD products with both test signals inside a CW bandwidth passband usually requires crystal controlled generators for reasons of low phase noise, especially if the receiver's in-passband odd-order dynamic range is large. Increasing bandwidth to allow much wider spacings of the test signals usually paints a false picture, because the signal handling capability of narrow bandwidth crystal filters is usually worse than that of the wider filters. 73, Geoff GM4ESD On Sunday, February 07, 2010 at 12:57 PM, Juan EA5RS <[hidden email]> wrote: Are you guys sure this is a frequency domain problem? Has anyone measured those IMD products under the mentioned conditions and concluded from the results that they are the culprit for the mushy (somewhat vague description) audio that makes impossible to copy the different callsigns? Some W6s measured in a lab test setup a similar effect on the FT1000MP years ago and found that the problem was the AGC recovering too fast (in between symbols) making all signals sound as loud as others. The solution was to increase the time constant. The loudest signal would then set the radio gain level. Then characters in-between from weaker signals sounded weaker making them distinct (or maybe buried). I cant think why you would ever need a recovery time constant any shorter than say 150 ms, while shorter time constants are normally used -reading Clifton I think the FAST setting in the K3 is 73 ms-. At 60 WPM, a dit is 20ms long if I am not mistaken, and an intersymbols spacing (7 time units) to full gain recovery seems the shortest time that would be necessary for the receiver to recover full gain. 73 de Juan EA5RS ______________________________________________________________ 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 |
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In reply to this post by Barry N1EU
I don't believe so. I'm recommending using only just enough RF/IF
gain to produce moderately low audio from ambient noise on a clear frequency. You can set the AGC threshold anywhere you want according to taste. Some are using NO AGC and the audio limiter to expand "threshold" to the audio limiter level. I'm proposing that there is a moderation point between one extreme of ambient noise shoved up into the AGC reduction range and the other of no AGC at all. And that changing RF gain during a pile up can maximize amplitude discrimination. Particularly for contests, NOT reducing the RF/IF gain per band on the lower bands just shoves the ambient noise up to a roar where the AGC winds up REDUCING wanted signals down to the level where noise has been BROUGHT UP, reducing the apparent signal to noise as perceived by the ear/brain combination to zero, a researched and documented phenomenon that has been quite appropriately reported by some here as "mush". This uncomfortable state is amplified in a pile up where most of the discrete signals become "noise" for hearing purposes, and the already used up threshold in the AGC forces them all to the same level. "Mush" is a very good description. (One experiment I recall is asking someone to identify individual conversations out of a monaural recording of a school cafeteria at lunchtime -- only the very loudest can be discerned.) AGC under squished circumstances can make "mush" all by itself without any help from a purported (but never carefully measured and reported) IMD "problem". The AGC threshold engages at a fixed voltage out of the RF/IF string for each step. Only the protective hardware AGC is operative before this point. If your setting of PRE/ATT/RFGAIN places ambient noise at what should be reserved for an S3 signal, you have subtracted that from your selected threshold range, no matter what your threshold preferences. And at worst case have already engaged AGC for the ambient noise. Threshold should allow one to have some range where any level difference in competing signals come through to allow ear/brain to tell them apart, AND still have a top where leveling kicks in to protect the ears. 73, Guy. On Sun, Feb 7, 2010 at 9:19 AM, Barry N1EU <[hidden email]> wrote: > > If you simply raise AGC Threshold, you will have to lower AF Gain or risk > overly loud audio from stronger signals. So what you would effectively be > doing is translating upwards the K3's dynamic range into higher rf levels. > This is NOT good practice - you want to keep the dynamic range operating at > lower rf levels (thus all the talk of gain throttling). > > 73, > Barry N1EU > > > Guy, K2AV wrote: >> >> This is true, but seems to be a VERY hard point to get across. Running >> excess gain in RF/IF strip is at the root of some number of >> complaints. >> >> On Sun, Feb 7, 2010 at 8:22 AM, Barry N1EU <[hidden email]> wrote: >>> If gain were throttled (e.g., via ATT on, PRE off, reduced RF Gain), >>> wouldn't AGC Threshold be effectively raised? 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 |
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