Mic Gain Changing
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Hi All, I have not done much SSB so I am not sure what is happening, but this does not seem correct so I will descibe what is happening. When I turn on my K3 #2080 for a MARS net I need to have the MIC gain set to about 25, and the Processor set to 15 for my HC5/Heil Proset to get about 95 Watts out initially, which I feel is excellent. However, after a few minutes I can turn down the gain and still get 95 Watts out. After about 10 minutes I have the MIC gain down to 8 and I am still blasting away at 95 Watts. I feel I could go even lower. Its funny though that at any gain level I always get a good report. Its like the MIC gain is really not critical and the rig knows how to adjust for your voice for best signal. I thought that maybe as I get used to speaking I start talking more forcefully and need to cut the gain down but I've consciously tried to avoid this, and the minimum apparent required MIC gain just seems to drop after a few minutes. Anyway the rig apparently works great like this. I just thought that this condition was not normal. 72, Steve, W2MY, AAR6CX _______________________________________________ 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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Are you maintaining a constant ALC indication of 5-7 bars at each gain
setting? Or is the ALC indication falling as you lower the gain setting? Bob NW8L On Tue, Jan 13, 2009 at 5:04 PM, <[hidden email]> wrote: > Hi All, > > I have not done much SSB so I am not sure what is happening, but this does > not seem correct so I will descibe what is happening. > > When I turn on my K3 #2080 for a MARS net I need to have the MIC gain set to > about 25, and the Processor set to 15 for my HC5/Heil Proset to get about 95 > Watts out initially, which I feel is excellent. However, after a few > minutes I can turn down the gain and still get 95 Watts out. After about 10 > minutes I have the MIC gain down to 8 and I am still blasting away at 95 > Watts. I feel I could go even lower. > > Its funny though that at any gain level I always get a good report. Its > like the MIC gain is really not critical and the rig knows how to adjust for > your voice for best signal. > > I thought that maybe as I get used to speaking I start talking more > forcefully and need to cut the gain down but I've consciously tried to avoid > this, and the minimum apparent required MIC gain just seems to drop after a > few minutes. > > Anyway the rig apparently works great like this. I just thought that this > condition was not normal. > > 72, > > Steve, W2MY, AAR6CX > > _______________________________________________ > 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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Hi Bob and All,
I got home and did USB NCS duties tonite on MARS so I have a little more information. It seems that when I first start transmitting even at a MIC gain of 25, I only initially get about 30 to 60 Watts of power out. If the Mic gain is 15 it is more like 35 Watts. If I keep the Mic gain set at 25 and just start talking while starting the net the power out keeps increasing for about 30 seconds until it is at about 100 Watts. The ALC is about 6 bars. At this point I can turn the Mic gain down to 2 and still get 100 Watts out and have an ALC of 6 bars. This is all done when the compression is set to 15 and is never changed. If is funny but we had to go from the operating frequency at about 3.2 MHz to about 2.3 MHz tonite. We did not have propagation at 2.3 MHz so we immediately went back to 3.2 MHz. I had to press the tune button to put a signal out at 5 W to tune the manual tuner as I always do. The Mic gain was still set to 25. However when I started talking I was putting out only about 35 W, so I just kept talking and the power rose to about 100 W again in about 30 seconds. Once again when I dropped the Mic gain down to 2, I still had 6 bars of ALC and 100 Watts out. Thats why I said that the ALC thing with the K3 was not critical and seemed to be self adjusting. Its just that I don't think my K3 #2080 is operating correctly. By the way I still get raving reports. I am heard with the K3 much better than the TS480. But I never used the processor with the TS480 so its apples and oranges until I do more tests with the TS480. Steve, W2MY -----Original Message----- From: [hidden email] [mailto:[hidden email]]On Behalf Of Bob Cunnings Sent: Tuesday, January 13, 2009 7:14 PM To: [hidden email] Subject: Re: [Elecraft] Mic Gain Changing Are you maintaining a constant ALC indication of 5-7 bars at each gain setting? Or is the ALC indication falling as you lower the gain setting? Bob NW8L _______________________________________________ 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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This sounds like the same thing Dave G4AON has mentioned in earlier posts. One thing worth pointing out is that it is not a good idea to tune at 5W or 50W. The K3 carries out a gain calibration when tuning is done at that exact power level, but it assumes when doing this that the load is a perfect 50 ohms. If it isn't, the calibration could be incorrect. If you tune at 6W (or even 5.1W) you should avoid this.
Julian, G4ILO. K2 #392 K3 #222 KX3 #110
* G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html |
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In reply to this post by list1
Hi All,
I have more information on this. I finished as NCS for the TX MARS net last night at 7:58 PM CT on about 3.2 MHz. The Mic gain functioned as I described in the previous email below. At 7:58 the Mic gain was set at 15 when I left the radio on to monitor the Oklahoma net on the same frequency at 8:01 pm. I was listening to the excellent audio from across the room. ;o) At 8:30 pm I heard a station I needed to contact so I went back to the radio. With the controls untouched, I called to check into the net. My output showed on the K3 at about 35 Watts again. When the NCS heard me I started transmitting and about 20 seconds after, I was back at 100 Watts. So now I am wondering if it has anything to do with temperature, or perhaps software temperature compensation. I do not have an external wattmeter installed for comparison purposes. I can try to do that, but it will take me some time to calibrate my old meter to confirm its approximate accuracy. Also I have not done the new auto power calibration in the new firmware yet as I know my dummy load is off by about 10%. Please any advice. Once again I must stress that the K3 is still performing very well. I was not supposed to be NCS last nite, but since I once again had the best signal in TX I was asked to take over the net (thanks to the K3). K3 #2080 is getting a nice reputation here in TX Army MARS. Steve, AAR6CX, W2MY ---------------------------------------------------------------------------- ---------- -----Original Message----- From: list1 [mailto:[hidden email]] Sent: Friday, January 16, 2009 8:20 PM To: Elecraft; Bob Cunnings Subject: RE:Mic Gain Changing Hi Bob and All, I got home and did USB NCS duties tonite on MARS so I have a little more information. It seems that when I first start transmitting even at a MIC gain of 25, I only initially get about 30 to 60 Watts of power out. If the Mic gain is 15 it is more like 35 Watts. If I keep the Mic gain set at 25 and just start talking while starting the net the power out keeps increasing for about 30 seconds until it is at about 100 Watts. The ALC is about 6 bars. At this point I can turn the Mic gain down to 2 and still get 100 Watts out and have an ALC of 6 bars. This is all done when the compression is set to 15 and is never changed. It is funny but we had to go from the operating frequency at about 3.2 MHz to about 2.3 MHz tonite. We did not have propagation at 2.3 MHz so we immediately went back to 3.2 MHz. I had to press the tune button to put a signal out at 5 W to tune the manual tuner as I always do. The Mic gain was still set to 25. However when I started talking I was putting out only about 35 W, so I just kept talking and the power rose to about 100 W again in about 30 seconds. Once again when I dropped the Mic gain down to 2, I still had 6 bars of ALC and 100 Watts out. Thats why I said that the ALC thing with the K3 was not critical and seemed to be self adjusting. Its just that I don't think my K3 #2080 is operating correctly. By the way I still get raving reports. I am heard with the K3 much better than the TS480. But I never used the processor with the TS480 so its apples and oranges until I do more tests with the TS480. Steve, W2MY _______________________________________________ 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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Hi Everyone,
OK I seemed to have "removed" the problem. I added 11 small resistors in parallel to my MFJ 949E dummy load to change its resistance from about 56.5 Ohms to close to 50.0 Ohms. I then ran the "Calibrate Transmitter Gain" procedure from the configuration Menu of the K3 utility. Now I can talk with 100 Watts and 6 bars of ALC all the time regardless of the temperature of the radio. No more fiddling with the Mic gain. Changing the Mic gain affects the power out and ALC reading now as expected. I think when I built my K3 I skipped the "TX Gain Calibration" step. I may have thought that it was optional like the Wattmeter calibration, but with my dummy load being off I think I was afraid that I would do more harm then good. I can now see how some people have problems with the K3 by not following instructions. I am a bit amazed the radio worked as well as it did in spite of the "loose nut in operator's chair" syndrome I was experiencing. OK, now to have even more fun with the radio, now that is it perfect. Steve, W2MY _______________________________________________ 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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Steve,
Your "confession" should be preserved in bold type for others to heed and lessons to be learned. Attempting to do calibrations with 'almost good enough' dummy loads (or other equipment too) will result in 'funny behavior' - one cannot obtain precision results with 'almost good enough' equipment. An accurate dummy load is the basis for many amateur measurements and calibrations. 1% 50 ohm dummy loads are not difficult to come by. A 100 watt dummy load can be built from a thick film power resistor (Caddock MP9100-50), a heat sink and a BNC, UHF, or N connector. These 50 ohm 1% resistors, when mounted on a heat sink with zero length leads to the connector, will be flat up to 200 MHz or more depending on the construction techniques. That kind of dummy load and a precision voltage reference (along with some basic math) have become the basis for calibrating other equipment on my workbench. I practice the "trust no measurement tool until it has proven its accuracy" rule. Good calibrated equipment does not need to be expensive, nor of laboratory quality, but it must be used intelligently with respect for its shortcomings. 73, Don W3FPR list1 wrote: > Hi Everyone, > > OK I seemed to have "removed" the problem. > > I added 11 small resistors in parallel to my MFJ 949E dummy load to change > its resistance from about 56.5 Ohms to close to 50.0 Ohms. I then ran the > "Calibrate Transmitter Gain" procedure from the configuration Menu of the K3 > utility. Now I can talk with 100 Watts and 6 bars of ALC all the time > regardless of the temperature of the radio. No more fiddling with the Mic > gain. Changing the Mic gain affects the power out and ALC reading now as > expected. > > I think when I built my K3 I skipped the "TX Gain Calibration" step. I may > have thought that it was optional like the Wattmeter calibration, but with > my dummy load being off I think I was afraid that I would do more harm then > good. > > I can now see how some people have problems with the K3 by not following > instructions. I am a bit amazed the radio worked as well as it did in spite > of the "loose nut in operator's chair" syndrome I was experiencing. > > OK, now to have even more fun with the radio, now that is it perfect. > > Steve, W2MY > > _______________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.10.9/1900 - Release Date: 1/18/2009 12:11 PM > > 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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Don:
I've purchased several surplus 75 watt high quality terminations from Ridge Equipment. These are cell site pulls, and are flat from DC up to 1 GHz plus and sell for $11.95. For a small amount more, Ridge will give you a return loss sweep. https://www.ridgeequipment.com/store/dummyloads.html is the URL for their loads page. Sometimes they will have Decibel Products 100 watt loads that, for ham purposes, are really 150 or 200 watt loads, but I don't see any listed at the moment. The 75 watt loads are OK at 75 watts but I would not push them past 100 or so watts for long periods. As I say, I have a couple of these and recommend them. Sure a lot better than the Heath Cantenna I built 40 years ago--and they don't leak. Jack K8ZOA Don Wilhelm wrote: > Steve, > > Your "confession" should be preserved in bold type for others to heed > and lessons to be learned. > > Attempting to do calibrations with 'almost good enough' dummy loads (or > other equipment too) will result in 'funny behavior' - one cannot obtain > precision results with 'almost good enough' equipment. > > An accurate dummy load is the basis for many amateur measurements and > calibrations. 1% 50 ohm dummy loads are not difficult to come by. A > 100 watt dummy load can be built from a thick film power resistor > (Caddock MP9100-50), a heat sink and a BNC, UHF, or N connector. These > 50 ohm 1% resistors, when mounted on a heat sink with zero length leads > to the connector, will be flat up to 200 MHz or more depending on the > construction techniques. That kind of dummy load and a precision > voltage reference (along with some basic math) have become the basis for > calibrating other equipment on my workbench. I practice the "trust no > measurement tool until it has proven its accuracy" rule. > > Good calibrated equipment does not need to be expensive, nor of > laboratory quality, but it must be used intelligently with respect for > its shortcomings. > > 73, > Don W3FPR > > > list1 wrote: > >> Hi Everyone, >> >> OK I seemed to have "removed" the problem. >> >> I added 11 small resistors in parallel to my MFJ 949E dummy load to change >> its resistance from about 56.5 Ohms to close to 50.0 Ohms. I then ran the >> "Calibrate Transmitter Gain" procedure from the configuration Menu of the K3 >> utility. Now I can talk with 100 Watts and 6 bars of ALC all the time >> regardless of the temperature of the radio. No more fiddling with the Mic >> gain. Changing the Mic gain affects the power out and ALC reading now as >> expected. >> >> I think when I built my K3 I skipped the "TX Gain Calibration" step. I may >> have thought that it was optional like the Wattmeter calibration, but with >> my dummy load being off I think I was afraid that I would do more harm then >> good. >> >> I can now see how some people have problems with the K3 by not following >> instructions. I am a bit amazed the radio worked as well as it did in spite >> of the "loose nut in operator's chair" syndrome I was experiencing. >> >> OK, now to have even more fun with the radio, now that is it perfect. >> >> Steve, W2MY >> >> _______________________________________________ >> 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 >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - http://www.avg.com >> Version: 8.0.176 / Virus Database: 270.10.9/1900 - Release Date: 1/18/2009 12:11 PM >> >> >> > _______________________________________________ > 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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