This weekend I will be participating in the Stew Perry 160M contest, as
will many of you. For the contest, I've arranged to do some testing of the IMD Mod as put forth by N6KR in a recent email. I will have two K3s available, one with the IMD mod (2uf in parallel with the .1uf already on the pcb) and one without the mod. The audio from each will be run to a sound card and one radio will be on the left channel, and the other radio on the right channel, so it will be easy to compare the two audio streams. K3s will be setup as follows: Same MCU and DSP firmware AGC parameters: DCY Soft HLD .30 PLS Nor SLP 000 THR 008 F 120 S 020 AGC as selected using front panel push button will be "slow". All RxEq will be flat, ie. 0 Preamp Off Att- haven't decided on this yet, but both radios will be the same. Crystal Filter- 400Hz Bandwidth setting- 400Hz Headphone audio from an SO2R Box will be routed to the sound card for recording. The program I use to record the audio will give me 1-hour wav files. RF gain adjusted to same number on both radios via N1MM Cat command Main Antenna will go through K3(1) Ant 1 jack K3(1) Ant Out will go to K3(2) Ant 1 Jack K3(2) will have power reduced to zero and in TEST mode K3(2) will also be put into transmit mode, but not keyed, when K3(1) is transmitting by using N1MM Cat commands {CAT2ASC TX;} CQ SP W1UE W1UE {CAT2ASC RX;} By putting K3(2) into Tx mode when keying K3(1), I'm figuring the front ends on both radios will not be damaged. The antenna in use will be a 160M 4-square, so I'm confident there will be plenty of signal for both rigs. If there is a better way to do this, I'm listening. So that I don't have to listen to 14 hours of audio to find some "mush", I will also be keeping a log of the times when I do hear it. I'm particularly interested to see if I can actually hear the difference in audio from this reduction in IMD. Comments as to my setup, and suggestions on other things that I may want to standardize, are appreciated. Dennis W1UE ______________________________________________________________ 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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Here's a link to the message from Wayne N6KR that Dennis W1UE is referring to. It's buried in a thread about contest scores.
http://elecraft.365791.n2.nabble.com/Fw-CQ-WW-DX-Contest-CW-2011-Unofficial-claimed-scores-tp7060148p7061538.html |
In reply to this post by Dennis Egan
Dennis,
Thanks for this try-out! I'm looking forward to hear the results. Some suggestions: - switch the PLS off. My experience in CW contests is that the PLS function will treat fast strong CW signals as pulses and will bypass the slow AGC for the first few dots of a signal. - maybe set the SLP to 8 or higher. This will make the AGC more active in your test - set AGC to F 73, Arie PA3A Op 14-12-2011 22:53, Dennis schreef: > AGC parameters: > DCY Soft > HLD .30 > PLS Nor > SLP 000 > THR 008 > F 120 > S 020 > AGC as selected using front panel push button will be "slow". > All RxEq will be flat, ie. 0 > Preamp Off > Att- haven't decided on this yet, but both radios will be the same. > Crystal Filter- 400Hz > Bandwidth setting- 400Hz > 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 |
Slope >0 flattens the agc response. Have a look at some curves on The AGC Story on ke7x.com
-----Original Message----- From: [hidden email] on behalf of Arie Kleingeld PA3A Sent: Thu 12/15/2011 3:08 AM To: [hidden email] Subject: Re: [Elecraft] K3 AGC Mod Test This Weekend Dennis, Thanks for this try-out! I'm looking forward to hear the results. Some suggestions: - switch the PLS off. My experience in CW contests is that the PLS function will treat fast strong CW signals as pulses and will bypass the slow AGC for the first few dots of a signal. - maybe set the SLP to 8 or higher. This will make the AGC more active in your test - set AGC to F 73, Arie PA3A Op 14-12-2011 22:53, Dennis schreef: > AGC parameters: > DCY Soft > HLD .30 > PLS Nor > SLP 000 > THR 008 > F 120 > S 020 > AGC as selected using front panel push button will be "slow". > All RxEq will be flat, ie. 0 > Preamp Off > Att- haven't decided on this yet, but both radios will be the same. > Crystal Filter- 400Hz > Bandwidth setting- 400Hz > 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 |
In reply to this post by Dennis Egan
Dennis I'd consider the following minor tweaks to your AGC settings:
HLD 0.20 AGS-S 040 Most importantly, set your RF Gain back so that the S-meters rest above the residual noise floor (including clicks, phase noise, etc). Once RF Gain is set, then adjust AF Gain to suit your ears/headphones. I would definitely try to find some pileups before the contest to confirm your AGC settings are not too slow for reasonable recovery in fast-paced exchanges. I would also not be using QSK. Of course you can try changing any of your settings during the contest to eliminate/induce mush. 73 & GL! Bill W4ZV |
In reply to this post by Cady, Fred
Fred,
Maybe I did not express it right: I want some more activity from the AGC means for me: audio response more flat with different signal levels. SLP 15 is most flat audio level in this case. 73, Arie PA3A Op 15-12-2011 15:17, Cady, Fred schreef: > > Slope >0 flattens the agc response. Have a look at some curves on The > AGC Story on ke7x.com > > > -----Original Message----- > > > > Some suggestions: > - switch the PLS off. My experience in CW contests is that the PLS > function will treat fast strong CW signals as pulses and will bypass the > slow AGC for the first few dots of a signal. > - maybe set the SLP to 8 or higher. This will make the AGC more active > in your test > - set AGC to F > > 73, > Arie PA3A > > 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 |
In reply to this post by Dennis Egan
Here are what I consider to be the best contest CW settings for
the K3: config AF GAIN = HIGH (to increase overall post-AGC gain) config AGC DCY = SOFT config AGC HLD = 0.20 config AGC PLS = NOR config AGC SLP = 000 (steepest) config AGC THR = 008 (highest) config AGC - F = 200 (fastest) config AGC - S = 020 Front panel select AGC FAST Front panel AF GAIN as loud as your ears can stand, 3 o'clock for me. Attenuator definitely ON, and preamp OFF for 160 (unless using separate RX antenna). Front Panel RF Gain set to show 1 or 2 S-units of band noise meter wiggle (about 1 o'clock for me) I know that selecting AGC SLOW on the front panel is supposed to reduce IMD, but for me, the mushiness is due to the aggressiveness of the K3's AGC curve, not IMD. Slow AGC also introduces desensing due to static crashes and other loud transients, so is undesirable for that reason. My next experiment will be to have an N1MM logging program macro available to send RF Gain command RG090 if a loud pileup shows up. RF Gain will be returned to 200 by appending the RG200 command to the "thank you" message. This should be the ultimate in "riding the RF gain control." Dave Hachadorian, K6LL Yuma, AZ -----Original Message----- From: Dennis Sent: Wednesday, December 14, 2011 2:53 PM To: [hidden email] Subject: [Elecraft] K3 AGC Mod Test This Weekend This weekend I will be participating in the Stew Perry 160M contest, as will many of you. For the contest, I've arranged to do some testing of the IMD Mod as put forth by N6KR in a recent email. I will have two K3s available, one with the IMD mod (2uf in parallel with the .1uf already on the pcb) and one without the mod. The audio from each will be run to a sound card and one radio will be on the left channel, and the other radio on the right channel, so it will be easy to compare the two audio streams. K3s will be setup as follows: Same MCU and DSP firmware AGC parameters: DCY Soft HLD .30 PLS Nor SLP 000 THR 008 F 120 S 020 AGC as selected using front panel push button will be "slow". All RxEq will be flat, ie. 0 Preamp Off Att- haven't decided on this yet, but both radios will be the same. Crystal Filter- 400Hz Bandwidth setting- 400Hz Headphone audio from an SO2R Box will be routed to the sound card for recording. The program I use to record the audio will give me 1-hour wav files. RF gain adjusted to same number on both radios via N1MM Cat command Main Antenna will go through K3(1) Ant 1 jack K3(1) Ant Out will go to K3(2) Ant 1 Jack K3(2) will have power reduced to zero and in TEST mode K3(2) will also be put into transmit mode, but not keyed, when K3(1) is transmitting by using N1MM Cat commands {CAT2ASC TX;} CQ SP W1UE W1UE {CAT2ASC RX;} By putting K3(2) into Tx mode when keying K3(1), I'm figuring the front ends on both radios will not be damaged. The antenna in use will be a 160M 4-square, so I'm confident there will be plenty of signal for both rigs. If there is a better way to do this, I'm listening. So that I don't have to listen to 14 hours of audio to find some "mush", I will also be keeping a log of the times when I do hear it. I'm particularly interested to see if I can actually hear the difference in audio from this reduction in IMD. Comments as to my setup, and suggestions on other things that I may want to standardize, are appreciated. Dennis W1UE ______________________________________________________________ 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 |
In reply to this post by Dennis Egan
Dave:
>My next experiment will be to have an N1MM logging program >macro available to send RF Gain command RG090 if a loud >pileup shows up. RF Gain will be returned to 200 by appending >the RG200 command to the "thank you" message. This should >be the ultimate in "riding the RF gain control." *EXCELLENT* idea! Thanks for the tip! -lu- ______________________________________________________________ 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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