K-3 Contest agc settings
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If you are a contester please respond off list. What AGC settings are
you using? In sprint last night I used the K-3 (first real contest) and I was less than thrilled with rx performance. Close by stations seemed to overload the rx. Something I didnt have with my MKV with the inrad mods and filters. Been fiddling with the settings but obviously dont have it right. filters in rig 2.8, 1.8 and 250 Mike/aj9c _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Others would like to know, please reply on list.
David G3UNA ----- Original Message ----- From: "Mike Kasrich" <[hidden email]> To: "Elecraft" <[hidden email]> Sent: Sunday, September 07, 2008 3:39 PM Subject: [Elecraft] K-3 Contest agc settings > If you are a contester please respond off list. What AGC settings are > you using? In sprint last night I used the K-3 (first real contest) and > I was less than thrilled with rx performance. Close by stations seemed > to overload the rx. Something I didnt have with my MKV with the inrad > mods and filters. Been fiddling with the settings but obviously dont > have it right. > > filters in rig 2.8, 1.8 and 250 > > Mike/aj9c > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Mike Kasrich
> If you are a contester please respond off list.
I chose to reply to the list because this is a topic of interest to many, whether contesting or not. > What AGC > settings are you using? In sprint last night I used the K-3 > (first real contest) and I was less than thrilled with rx > performance. Close by stations seemed to overload the rx. > Something I didnt have with my MKV with the inrad mods and > filters. Been fiddling with the settings but obviously dont > have it right. All my operating is contesting and I've used two K3s for a year now. At home, there are several local contesters just a few miles line-of-sight off the back lobes of my Yagis. At 1.5 KW they saturate my S-meters. Still, they are unnoticeable when outside my filters and I'm usually run the default AGC settings. Most people have reported just the opposite comparison between the MKV and K3, i.e., they prefer the K3 RX in contest or crowded band conditions with strong signals nearby. The PREamp has more impact on RX overload than the AGC in most cases. On the low bands, you may even need to engage the ATTenuator. Don't make the AGC do all the work by slamming it with too much signal strength. Certainly, you can optimize the AGC for different conditions by changing the threshold and slope. For many it is a matter of personal preference more than an absolute "correct" setting. You will probably want higher thresholds on the lower bands due to the noise level. The slope is a trade-off between reducing gain for strong signals and still having discrimination between different signal strengths. If you keep the front-end tamed down with appropriate PRE and ATT engagements, then you will find the AGC gives you fine control over the range of signal strengths rather than relying on it alone for dealing with the very strong signals. > filters in rig 2.8, 1.8 and 250 Remember your "250" filter is really 370 Hz at the -6 dB points, so you might have it engage at DSP bandwidth of 350 or 300 Hz. But even at 350, the cascade effect will produce an overall bandwidth of less than 300 Hz, which is a bit narrow for CW contesting, IMO. At DSP WIDTHs of 400-500 Hz, your roofing filter will be the 1.8 kHz, if you have it configured "normally", so that doesn't give you IMD protection for the DSP with very strong signals located between your DSP and crystal filter widths. (I should point out that some K3 ops don't subscribe to the K3 design that deploys the crystal filters as roofing filters that are set wider than the DSP WIDTHs to protect the DSP. Instead they prefer the passband shape of the crystal filter and effectively eliminate the DSP filter by configuring their K3 filtering to have the crystal filter engage at DSP bandwidths GREATER than the crystal filter. Until the DSP WIDTH is reduced to well within the crystal filter bandwidth, the crystal filter is dominating the passband shape and filtering. Of course, the DSP will still provide steeper skirts at a point well below the passband.) 73, Ed - W0YK P.S. Thanks for the Sprint Qs! _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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On Sun, 7 Sep 2008 08:51:19 -0700, Ed Muns wrote:
>The PREamp has more impact on RX overload than the AGC in most cases. On >the low bands, you may even need to engage the ATTenuator. Don't make the >AGC do all the work by slamming it with too much signal strength. I'm one of those guys not far from Ed, and I agree with all of his comments. I had the preamp off on 20M; on 80 amd 40M, I had the preamp off and the attenuator engaged. I am VERY pleased with how well the K3 stands up in a crowded band. I have 400 Hz roofing filters in both of my K3s. One of them also has a 1.8 kHz filter, and I'll probably add one to the other one. There were several times last night when I took the IF down to 50 or 100 Hz to pull someone out! 73, Jim K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by David Cutter
Exactly!
We'd all like to know the contesters secrets, please reply ONLIST thank you. 73, Deni F5VJC David Cutter wrote: > Others would like to know, please reply on list. > > David > G3UNA > > ----- Original Message ----- From: "Mike Kasrich" <[hidden email]> > To: "Elecraft" <[hidden email]> > Sent: Sunday, September 07, 2008 3:39 PM > Subject: [Elecraft] K-3 Contest agc settings > > >> If you are a contester please respond off list. What AGC settings >> are you using? In sprint last night I used the K-3 (first real >> contest) and I was less than thrilled with rx performance. Close by >> stations seemed to overload the rx. Something I didnt have with my >> MKV with the inrad mods and filters. Been fiddling with the settings >> but obviously dont have it right. >> >> filters in rig 2.8, 1.8 and 250 >> >> Mike/aj9c >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- 73, Deni F5VJC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Ed Muns, W0YK
Ed ....
If I understand what I think you said, the agc settings are dependant on: Pre-amp on/off and / or Attenuator on/off The DSP filter width Which 1st IF filter is active and ..... the AGC SLP and THR settings are, for the most part a well kept secret and not to be shared. However mine are SLP= 8 and THR= 4 and, to me, it sounds pretty close to the K2. I don't use NR much on CW because of what it appears to do to the received CW signals. This is with MCU 2.34 and DSP 1.81, which may affect how those two settings are set. If SLP= 8 and THR= 4 are bad settings, please tell me why. 73 Hank K8DD ----- Original Message ----- From: "Ed Muns" <[hidden email]> To: "'Mike Kasrich'" <[hidden email]> Cc: "'Elecraft'" <[hidden email]> Sent: Sunday, September 07, 2008 11:51 AM Subject: RE: [Elecraft] K-3 Contest agc settings >> If you are a contester please respond off list. > > I chose to reply to the list because this is a topic of interest to many, > whether contesting or not. > >> What AGC >> settings are you using? In sprint last night I used the K-3 >> (first real contest) and I was less than thrilled with rx >> performance. Close by stations seemed to overload the rx. >> Something I didnt have with my MKV with the inrad mods and >> filters. Been fiddling with the settings but obviously dont >> have it right. > > All my operating is contesting and I've used two K3s for a year now. At > home, there are several local contesters just a few miles line-of-sight > off > the back lobes of my Yagis. At 1.5 KW they saturate my S-meters. Still, > they are unnoticeable when outside my filters and I'm usually run the > default AGC settings. Most people have reported just the opposite > comparison between the MKV and K3, i.e., they prefer the K3 RX in contest > or > crowded band conditions with strong signals nearby. > > The PREamp has more impact on RX overload than the AGC in most cases. On > the low bands, you may even need to engage the ATTenuator. Don't make the > AGC do all the work by slamming it with too much signal strength. > Certainly, you can optimize the AGC for different conditions by changing > the > threshold and slope. For many it is a matter of personal preference more > than an absolute "correct" setting. You will probably want higher > thresholds on the lower bands due to the noise level. The slope is a > trade-off between reducing gain for strong signals and still having > discrimination between different signal strengths. If you keep the > front-end tamed down with appropriate PRE and ATT engagements, then you > will > find the AGC gives you fine control over the range of signal strengths > rather than relying on it alone for dealing with the very strong signals. > >> filters in rig 2.8, 1.8 and 250 > > Remember your "250" filter is really 370 Hz at the -6 dB points, so you > might have it engage at DSP bandwidth of 350 or 300 Hz. But even at 350, > the cascade effect will produce an overall bandwidth of less than 300 Hz, > which is a bit narrow for CW contesting, IMO. At DSP WIDTHs of 400-500 > Hz, > your roofing filter will be the 1.8 kHz, if you have it configured > "normally", so that doesn't give you IMD protection for the DSP with very > strong signals located between your DSP and crystal filter widths. > > (I should point out that some K3 ops don't subscribe to the K3 design that > deploys the crystal filters as roofing filters that are set wider than the > DSP WIDTHs to protect the DSP. Instead they prefer the passband shape of > the crystal filter and effectively eliminate the DSP filter by configuring > their K3 filtering to have the crystal filter engage at DSP bandwidths > GREATER than the crystal filter. Until the DSP WIDTH is reduced to well > within the crystal filter bandwidth, the crystal filter is dominating the > passband shape and filtering. Of course, the DSP will still provide > steeper > skirts at a point well below the passband.) > > 73, > Ed - W0YK > > P.S. Thanks for the Sprint Qs! > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > ____________________________________________________________ Make more on your investments with qualified asset management. Click now! http://thirdpartyoffers.netzero.net/TGL2241/fc/Ioyw6i4ulIRaB5K0PWBazTvoDcbraYe7ekPFGhkhT1cWPPgui57Yhd/ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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> Ed ....
> > If I understand what I think you said, the agc settings are > dependant on: > Pre-amp on/off and / or Attenuator on/off > The DSP filter width > Which 1st IF filter is active What I intended to convey was that to prevent overload, one should first make sure the front-end gain is not too high before worrying about AGC settings. Independent of AGC, the RX front-end can be too hot if the PREamp is enabled, e.g., on 40 - 160 especially, or if the ATTentuator is off on the low bands when signals are pounding in. My point about RX overload was to first turn off the PREamp and add the ATTenuator if required. The second point is to use the crystal filters as roofing filters to protect the DSP as the K3 was designed. The tighter they are around the DSP WIDTH you are using, the better protected the DSP is from nearby strong signal IMD. THEN, worry about setting the AGC parameters to optimize to your preference. It is futile to deal with RX overload with only the AGC if you've got the front-end too hot and have wide roofing filters letting IMD be created in your passband. > and ..... > the AGC SLP and THR settings are, for the most part a well > kept secret and not to be shared. Few people change the AGC settings from the default and even fewer people understand what the AGC settings do and how to adjust them to achieve what you want. This reflector has had some good posts on AGC parameters from W8JI and K8ZOA. So, I don't think AGC settings are secret and not to be shared so much as they are not well understood by many of us. Moreover, there is no single set of magic or ideal AGC settings for everyone and everyone's operating variations. The K3 defaults are probably the best single set of parameters for all of us. They may not be optimum in all situations, but they won't be terribly wrong either. > However mine are SLP= 8 and THR= 4 and, to me, it sounds > pretty close to the K2. I don't use NR much on CW because of > what it appears to do to the received CW signals. > This is with MCU 2.34 and DSP 1.81, which may affect how > those two settings are set. I'm using the defaults of SLP=010, THR=005, HLD=000, AGC-F=120 for CW. I used 2.38 and 1.90 in the CW Sprint last night. Wayne updated 2.38 fifteen minutes before the Sprint to fix a minor issue with how RIT Clear was working from our contest loggers. Both my K3s and at least two others updated with this firmware and ran flawlessly. (Those of you who worry about Beta releases posted on the Elecraft web site, take note. For 15 months now, I have always updated to the latest K3 firmware, even this close to the start of a contest. I would never do that with any other software or firmware. The K3 firmware updates are not perfect, but I have high confidence in them.) > If SLP= 8 and THR= 4 are bad settings, please tell me why. I don't think those are bad settings, but I haven't operated your K3 at your location at the times you operate, etc., etc. The whole range of possible AGC settings is reasonable depending on operating conditions and personal preference. Personally, the default AGC settings have worked well for me, so I haven't invested the time to experiment. Changing AGC settings is not something you can do and immediately know if they are "better". This is because every signal and band and noise situation is different, so you need to experience the AGC settings over a range of operating conditions. You may want to change one, or at most two, parameters at a time and operate with them for a while to anecdotally compare to the previous settings. Over time you can get a feel for how much change in each will effect your receiving performance in various conditions. I suppose one could put SLP and THR on Programmable Function keys and adjust them real time on signals, but I've not found that to be a priority compared to other things I need to be worrying about while operating. If I need to reduce gain quickly, I reach for the RF GAIN knob. If I feel the AGC is getting in my way, I may even turn it off and just ride the RF GAIN control. Most of the K3s at VP6DX were operated with the AGC off, so AGC parameter values were irrelevant in their rather challenging conditions. Still, I'm looking forward to playing with the AGC parameters some more and trying to optimize them for my various operating scenarios, but it is not a high priority need right now. To summarize, RX overload should be first dealt with by using the PREamp and ATTenuator to achieve the right amount of gain in the front-end. Once that is set properly, then you can use the RF GAIN control and/or the AGC parameters to fine tune performance. You mentioned NR. I haven't found NR to be useful at all for CW, and while it works well on SSB, I don't use it there either, preferring to let my brain deal with the noise. 73, Ed - W0YK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by hank_k8dd
I have found that I tailor the AGC to the types of signals I am
working with. Jacks articles were a big help with understanding what is going on ( cliffton labs ). If I am play with weak DX signals, I tend to keep the AGC levels a bit hard, meaning louder. Low signals low, high signals high. I have also used this, and RF gain together in a contest, to dig weaker signals out between the big guns. When in the midst of lots of big guns, I have to flatten the signals out so that my ears are not shorted out by the big signals coming in. David Wilburn K4DGW H Kohl wrote: > Ed .... > > If I understand what I think you said, the agc settings are > dependant on: > Pre-amp on/off and / or Attenuator on/off > The DSP filter width > Which 1st IF filter is active > > and ..... > the AGC SLP and THR settings are, for the most part a > well kept secret and not to be shared. > > However mine are SLP= 8 and THR= 4 and, to me, it > sounds pretty close to the K2. I don't use NR much on > CW because of what it appears to do to the received CW > signals. > This is with MCU 2.34 and DSP 1.81, which may affect > how those two settings are set. > > If SLP= 8 and THR= 4 are bad settings, please tell me > why. > > 73 Hank K8DD > > > > ----- Original Message ----- From: "Ed Muns" <[hidden email]> > To: "'Mike Kasrich'" <[hidden email]> > Cc: "'Elecraft'" <[hidden email]> > Sent: Sunday, September 07, 2008 11:51 AM > Subject: RE: [Elecraft] K-3 Contest agc settings > > >>> If you are a contester please respond off list. >> >> I chose to reply to the list because this is a topic of interest to many, >> whether contesting or not. >> >>> What AGC >>> settings are you using? In sprint last night I used the K-3 >>> (first real contest) and I was less than thrilled with rx >>> performance. Close by stations seemed to overload the rx. >>> Something I didnt have with my MKV with the inrad mods and >>> filters. Been fiddling with the settings but obviously dont >>> have it right. >> >> All my operating is contesting and I've used two K3s for a year now. At >> home, there are several local contesters just a few miles >> line-of-sight off >> the back lobes of my Yagis. At 1.5 KW they saturate my S-meters. Still, >> they are unnoticeable when outside my filters and I'm usually run the >> default AGC settings. Most people have reported just the opposite >> comparison between the MKV and K3, i.e., they prefer the K3 RX in >> contest or >> crowded band conditions with strong signals nearby. >> >> The PREamp has more impact on RX overload than the AGC in most cases. On >> the low bands, you may even need to engage the ATTenuator. Don't make >> the >> AGC do all the work by slamming it with too much signal strength. >> Certainly, you can optimize the AGC for different conditions by >> changing the >> threshold and slope. For many it is a matter of personal preference more >> than an absolute "correct" setting. You will probably want higher >> thresholds on the lower bands due to the noise level. The slope is a >> trade-off between reducing gain for strong signals and still having >> discrimination between different signal strengths. If you keep the >> front-end tamed down with appropriate PRE and ATT engagements, then >> you will >> find the AGC gives you fine control over the range of signal strengths >> rather than relying on it alone for dealing with the very strong signals. >> >>> filters in rig 2.8, 1.8 and 250 >> >> Remember your "250" filter is really 370 Hz at the -6 dB points, so you >> might have it engage at DSP bandwidth of 350 or 300 Hz. But even at 350, >> the cascade effect will produce an overall bandwidth of less than 300 Hz, >> which is a bit narrow for CW contesting, IMO. At DSP WIDTHs of >> 400-500 Hz, >> your roofing filter will be the 1.8 kHz, if you have it configured >> "normally", so that doesn't give you IMD protection for the DSP with very >> strong signals located between your DSP and crystal filter widths. >> >> (I should point out that some K3 ops don't subscribe to the K3 design >> that >> deploys the crystal filters as roofing filters that are set wider than >> the >> DSP WIDTHs to protect the DSP. Instead they prefer the passband shape of >> the crystal filter and effectively eliminate the DSP filter by >> configuring >> their K3 filtering to have the crystal filter engage at DSP bandwidths >> GREATER than the crystal filter. Until the DSP WIDTH is reduced to well >> within the crystal filter bandwidth, the crystal filter is dominating the >> passband shape and filtering. Of course, the DSP will still provide >> steeper >> skirts at a point well below the passband.) >> >> 73, >> Ed - W0YK >> >> P.S. Thanks for the Sprint Qs! >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> > > ____________________________________________________________ > Make more on your investments with qualified asset management. Click now! > http://thirdpartyoffers.netzero.net/TGL2241/fc/Ioyw6i4ulIRaB5K0PWBazTvoDcbraYe7ekPFGhkhT1cWPPgui57Yhd/ > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by David Cutter
> Close by stations seemed
> to overload the rx. <snip...> > > filters in rig 2.8, 1.8 and 250 Unless you run with WIDTH under 300, you're going to have problems with strong signals overloading the AGC. That's what the roofing filters are for. The 1.8 and 2.8 will allow signals you can't even hear to affect the AGC. The 250 is fine, but you'll miss stations outside your passband responding to your CQ. For CW contesting, you really need the 500 Hz or 400 Hz filter. 73, Dick WC1M _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by dave.wilburn
Get Elecraft to fix ur radio so that the AGC works better, early versions out of the box necessitated turning off AGC and riding RF Gain, like the first DXpeditioners did. Those who say K3 AGC is ok either got a good one or got it fixed later. 73 Charles Harpole [hidden email] > Date: Mon, 8 Sep 2008 09:35:39 -0400 > From: [hidden email] > Subject: Re: [Elecraft] K-3 Contest agc settings > To: [hidden email] > > I have found that I tailor the AGC to the types of signals I am > working with. Jacks articles were a big help with understanding what > is going on ( cliffton labs ). > > If I am play with weak DX signals, I tend to keep the AGC levels a bit > hard, meaning louder. Low signals low, high signals high. I have > also used this, and RF gain together in a contest, to dig weaker > signals out between the big guns. > > When in the midst of lots of big guns, I have to flatten the signals > out so that my ears are not shorted out by the big signals coming in. > > David Wilburn > K4DGW > > > > > H Kohl wrote: >> Ed .... >> >> If I understand what I think you said, the agc settings are >> dependant on: >> Pre-amp on/off and / or Attenuator on/off >> The DSP filter width >> Which 1st IF filter is active >> >> and ..... >> the AGC SLP and THR settings are, for the most part a >> well kept secret and not to be shared. >> >> However mine are SLP= 8 and THR= 4 and, to me, it >> sounds pretty close to the K2. I don't use NR much on >> CW because of what it appears to do to the received CW >> signals. >> This is with MCU 2.34 and DSP 1.81, which may affect >> how those two settings are set. >> >> If SLP= 8 and THR= 4 are bad settings, please tell me >> why. >> >> 73 Hank K8DD >> >> >> >> ----- Original Message ----- From: "Ed Muns" >> To: "'Mike Kasrich'" >> Cc: "'Elecraft'" >> Sent: Sunday, September 07, 2008 11:51 AM >> Subject: RE: [Elecraft] K-3 Contest agc settings >> >> >>>> If you are a contester please respond off list. >>> >>> I chose to reply to the list because this is a topic of interest to many, >>> whether contesting or not. >>> >>>> What AGC >>>> settings are you using? In sprint last night I used the K-3 >>>> (first real contest) and I was less than thrilled with rx >>>> performance. Close by stations seemed to overload the rx. >>>> Something I didnt have with my MKV with the inrad mods and >>>> filters. Been fiddling with the settings but obviously dont >>>> have it right. >>> >>> All my operating is contesting and I've used two K3s for a year now. At >>> home, there are several local contesters just a few miles >>> line-of-sight off >>> the back lobes of my Yagis. At 1.5 KW they saturate my S-meters. Still, >>> they are unnoticeable when outside my filters and I'm usually run the >>> default AGC settings. Most people have reported just the opposite >>> comparison between the MKV and K3, i.e., they prefer the K3 RX in >>> contest or >>> crowded band conditions with strong signals nearby. >>> >>> The PREamp has more impact on RX overload than the AGC in most cases. On >>> the low bands, you may even need to engage the ATTenuator. Don't make >>> the >>> AGC do all the work by slamming it with too much signal strength. >>> Certainly, you can optimize the AGC for different conditions by >>> changing the >>> threshold and slope. For many it is a matter of personal preference more >>> than an absolute "correct" setting. You will probably want higher >>> thresholds on the lower bands due to the noise level. The slope is a >>> trade-off between reducing gain for strong signals and still having >>> discrimination between different signal strengths. If you keep the >>> front-end tamed down with appropriate PRE and ATT engagements, then >>> you will >>> find the AGC gives you fine control over the range of signal strengths >>> rather than relying on it alone for dealing with the very strong signals. >>> >>>> filters in rig 2.8, 1.8 and 250 >>> >>> Remember your "250" filter is really 370 Hz at the -6 dB points, so you >>> might have it engage at DSP bandwidth of 350 or 300 Hz. But even at 350, >>> the cascade effect will produce an overall bandwidth of less than 300 Hz, >>> which is a bit narrow for CW contesting, IMO. At DSP WIDTHs of >>> 400-500 Hz, >>> your roofing filter will be the 1.8 kHz, if you have it configured >>> "normally", so that doesn't give you IMD protection for the DSP with very >>> strong signals located between your DSP and crystal filter widths. >>> >>> (I should point out that some K3 ops don't subscribe to the K3 design >>> that >>> deploys the crystal filters as roofing filters that are set wider than >>> the >>> DSP WIDTHs to protect the DSP. Instead they prefer the passband shape of >>> the crystal filter and effectively eliminate the DSP filter by >>> configuring >>> their K3 filtering to have the crystal filter engage at DSP bandwidths >>> GREATER than the crystal filter. Until the DSP WIDTH is reduced to well >>> within the crystal filter bandwidth, the crystal filter is dominating the >>> passband shape and filtering. Of course, the DSP will still provide >>> steeper >>> skirts at a point well below the passband.) >>> >>> 73, >>> Ed - W0YK >>> >>> P.S. Thanks for the Sprint Qs! >>> >>> _______________________________________________ >>> Elecraft mailing list >>> Post to: [hidden email] >>> You must be a subscriber to post to the list. >>> Subscriber Info (Addr. Change, sub, unsub etc.): >>> http://mailman.qth.net/mailman/listinfo/elecraft >>> >>> Help: http://mailman.qth.net/subscribers.htm >>> Elecraft web page: http://www.elecraft.com >>> >> >> ____________________________________________________________ >> Make more on your investments with qualified asset management. Click now! >> http://thirdpartyoffers.netzero.net/TGL2241/fc/Ioyw6i4ulIRaB5K0PWBazTvoDcbraYe7ekPFGhkhT1cWPPgui57Yhd/ >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Actually the AGC works quite well, and it is post AGC mod model. I am
merely taking advantage of the fact that the AGC is configurable. I do not "have" to make the changes, but due to the radio's flexibility, I am able to make the changes, and that helps with weak signals. On the other hand, if there are strong signals near the weak, then I can turn the AGC back towards "normal" or "tolerable" levels. At this point signals have the same audio levels regardless of RF levels. By reading Jacks articles, a better understanding of the various settings can be obtained, and the various settings can be implemented to tackle various "obstacles". Making the rig more configurable and useful to the operator. David Wilburn K4DGW Charles Harpole wrote: > Get Elecraft to fix ur radio so that the AGC works > > better, early versions out of the box necessitated > > turning off AGC and riding RF Gain, like the first > > DXpeditioners did. Those who say K3 AGC is ok > > either got a good one or got it fixed later. > > 73 > > > Charles Harpole > > > [hidden email] > > > > > >> Date: Mon, 8 Sep 2008 09:35:39 -0400 >> From: [hidden email] >> Subject: Re: [Elecraft] K-3 Contest agc settings >> To: [hidden email] >> >> I have found that I tailor the AGC to the types of signals I am >> working with. Jacks articles were a big help with understanding what >> is going on ( cliffton labs ). >> >> If I am play with weak DX signals, I tend to keep the AGC levels a bit >> hard, meaning louder. Low signals low, high signals high. I have >> also used this, and RF gain together in a contest, to dig weaker >> signals out between the big guns. >> >> When in the midst of lots of big guns, I have to flatten the signals >> out so that my ears are not shorted out by the big signals coming in. >> >> David Wilburn >> K4DGW >> >> >> >> >> H Kohl wrote: >>> Ed .... >>> >>> If I understand what I think you said, the agc settings are >>> dependant on: >>> Pre-amp on/off and / or Attenuator on/off >>> The DSP filter width >>> Which 1st IF filter is active >>> >>> and ..... >>> the AGC SLP and THR settings are, for the most part a >>> well kept secret and not to be shared. >>> >>> However mine are SLP= 8 and THR= 4 and, to me, it >>> sounds pretty close to the K2. I don't use NR much on >>> CW because of what it appears to do to the received CW >>> signals. >>> This is with MCU 2.34 and DSP 1.81, which may affect >>> how those two settings are set. >>> >>> If SLP= 8 and THR= 4 are bad settings, please tell me >>> why. >>> >>> 73 Hank K8DD >>> >>> >>> >>> ----- Original Message ----- From: "Ed Muns" >>> To: "'Mike Kasrich'" >>> Cc: "'Elecraft'" >>> Sent: Sunday, September 07, 2008 11:51 AM >>> Subject: RE: [Elecraft] K-3 Contest agc settings >>> >>> >>>>> If you are a contester please respond off list. >>>> I chose to reply to the list because this is a topic of interest to many, >>>> whether contesting or not. >>>> >>>>> What AGC >>>>> settings are you using? In sprint last night I used the K-3 >>>>> (first real contest) and I was less than thrilled with rx >>>>> performance. Close by stations seemed to overload the rx. >>>>> Something I didnt have with my MKV with the inrad mods and >>>>> filters. Been fiddling with the settings but obviously dont >>>>> have it right. >>>> All my operating is contesting and I've used two K3s for a year now. At >>>> home, there are several local contesters just a few miles >>>> line-of-sight off >>>> the back lobes of my Yagis. At 1.5 KW they saturate my S-meters. Still, >>>> they are unnoticeable when outside my filters and I'm usually run the >>>> default AGC settings. Most people have reported just the opposite >>>> comparison between the MKV and K3, i.e., they prefer the K3 RX in >>>> contest or >>>> crowded band conditions with strong signals nearby. >>>> >>>> The PREamp has more impact on RX overload than the AGC in most cases. On >>>> the low bands, you may even need to engage the ATTenuator. Don't make >>>> the >>>> AGC do all the work by slamming it with too much signal strength. >>>> Certainly, you can optimize the AGC for different conditions by >>>> changing the >>>> threshold and slope. For many it is a matter of personal preference more >>>> than an absolute "correct" setting. You will probably want higher >>>> thresholds on the lower bands due to the noise level. The slope is a >>>> trade-off between reducing gain for strong signals and still having >>>> discrimination between different signal strengths. If you keep the >>>> front-end tamed down with appropriate PRE and ATT engagements, then >>>> you will >>>> find the AGC gives you fine control over the range of signal strengths >>>> rather than relying on it alone for dealing with the very strong signals. >>>> >>>>> filters in rig 2.8, 1.8 and 250 >>>> Remember your "250" filter is really 370 Hz at the -6 dB points, so you >>>> might have it engage at DSP bandwidth of 350 or 300 Hz. But even at 350, >>>> the cascade effect will produce an overall bandwidth of less than 300 Hz, >>>> which is a bit narrow for CW contesting, IMO. At DSP WIDTHs of >>>> 400-500 Hz, >>>> your roofing filter will be the 1.8 kHz, if you have it configured >>>> "normally", so that doesn't give you IMD protection for the DSP with very >>>> strong signals located between your DSP and crystal filter widths. >>>> >>>> (I should point out that some K3 ops don't subscribe to the K3 design >>>> that >>>> deploys the crystal filters as roofing filters that are set wider than >>>> the >>>> DSP WIDTHs to protect the DSP. Instead they prefer the passband shape of >>>> the crystal filter and effectively eliminate the DSP filter by >>>> configuring >>>> their K3 filtering to have the crystal filter engage at DSP bandwidths >>>> GREATER than the crystal filter. Until the DSP WIDTH is reduced to well >>>> within the crystal filter bandwidth, the crystal filter is dominating the >>>> passband shape and filtering. Of course, the DSP will still provide >>>> steeper >>>> skirts at a point well below the passband.) >>>> >>>> 73, >>>> Ed - W0YK >>>> >>>> P.S. Thanks for the Sprint Qs! >>>> >>>> _______________________________________________ >>>> Elecraft mailing list >>>> Post to: [hidden email] >>>> You must be a subscriber to post to the list. >>>> Subscriber Info (Addr. Change, sub, unsub etc.): >>>> http://mailman.qth.net/mailman/listinfo/elecraft >>>> >>>> Help: http://mailman.qth.net/subscribers.htm >>>> Elecraft web page: http://www.elecraft.com >>>> >>> ____________________________________________________________ >>> Make more on your investments with qualified asset management. Click now! >>> http://thirdpartyoffers.netzero.net/TGL2241/fc/Ioyw6i4ulIRaB5K0PWBazTvoDcbraYe7ekPFGhkhT1cWPPgui57Yhd/ >>> >>> _______________________________________________ >>> Elecraft mailing list >>> Post to: [hidden email] >>> You must be a subscriber to post to the list. >>> Subscriber Info (Addr. Change, sub, unsub etc.): >>> http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/subscribers.htm >>> Elecraft web page: http://www.elecraft.com >>> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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