Re: K3 Beta firmware rev. 2.57
Locked
 
|
Wayne, the AM power level in this version only seems to produce a
carrier of 10 Watts when the requested power is "100W". While I don't agree with the idea of calling the power anything other than the carrier level, i.e. I would expect the power control to only go to about 30 Watts on AM, 10 Watts is only 1/3rd of the carrier power a 100 W nominal transceiver should produce. Back to the drawing board? 73 Dave, G4AON K3/100 #80 ========================================== * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation percentage. _______________________________________________ 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 |
SV: K3 Beta firmware rev. 2.57
|
|
GM all, not that I am one of those AM guys but just checked my K3 which produces 45W on 160 and 40W on 80. Maybe some set up trouble, Dave? 73 Len SM7BIC Wayne, the AM power level in this version only seems to produce a carrier of 10 Watts when the requested power is "100W". While I don't agree with the idea of calling the power anything other than the carrier level, i.e. I would expect the power control to only go to about 30 Watts on AM, 10 Watts is only 1/3rd of the carrier power a 100 W nominal transceiver should produce. Back to the drawing board? 73 Dave, G4AON K3/100 #80 ========================================== * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation percentage. _______________________________________________ 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 |
|
|
Len
I checked the calibration at 5 and 50 Watts, the carrier power is close to the power control setting at other power settings too. Earlier firmware gives higher power, although still short of the expected 25 - 40 Watt carrier. I have gone back to f/w version 2.46, although that has useless AM TX audio as there is no compression. I was checking on 80m into a 50 Ohm load. I'm not too worried about AM as I rarely use it, but it should be implemented better than it is. 73 Dave, G4AON --------------------------------------------- Lennart Michaëlsson wrote: > GM all, > not that I am one of those AM guys but just checked my K3 which produces 45W > on 160 and 40W on 80. > Maybe some set up trouble, Dave? > 73 > Len > SM7BIC > > Wayne, the AM power level in this version only seems to produce a > carrier of 10 Watts when the requested power is "100W". While I don't > agree with the idea of calling the power anything other than the carrier > level, i.e. I would expect the power control to only go to about 30 > Watts on AM, 10 Watts is only 1/3rd of the carrier power a 100 W nominal > transceiver should produce. > > Back to the drawing board? > > 73 Dave, G4AON > K3/100 #80 > ========================================== > > * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation > percentage. > > _______________________________________________ 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 |
SV: K3 Beta firmware rev. 2.57
|
|
Dave, I agree with you - there is "something odd going on". Then, perhaps the power level setting should be renamed to PEP output instead? Let us see what Wayne finds out (in due time) One more early morning on 160 with SSB contest going on it was possible to work some NA westcoast on CW with an outstanding K3, the diversity really is amazing! 73 Len SM7BIC Len I checked the calibration at 5 and 50 Watts, the carrier power is close to the power control setting at other power settings too. Earlier firmware gives higher power, although still short of the expected 25 - 40 Watt carrier. I have gone back to f/w version 2.46, although that has useless AM TX audio as there is no compression. I was checking on 80m into a 50 Ohm load. I'm not too worried about AM as I rarely use it, but it should be implemented better than it is. 73 Dave, G4AON --------------------------------------------- Lennart Michaëlsson wrote: > GM all, > not that I am one of those AM guys but just checked my K3 which produces 45W > on 160 and 40W on 80. > Maybe some set up trouble, Dave? > 73 > Len > SM7BIC > > Wayne, the AM power level in this version only seems to produce a > carrier of 10 Watts when the requested power is "100W". While I don't > agree with the idea of calling the power anything other than the carrier > level, i.e. I would expect the power control to only go to about 30 > Watts on AM, 10 Watts is only 1/3rd of the carrier power a 100 W nominal > transceiver should produce. > > Back to the drawing board? > > 73 Dave, G4AON > K3/100 #80 > ========================================== > > * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation > percentage. > > _______________________________________________ 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 |
Re: SV: K3 Beta firmware rev. 2.57
|
|
In reply to this post by Lennart Michaëlsson
I have the TxG VCE set to -1.5 db in order to avoid excessive peak SSB
power levels compared to CW levels... If I set it to 0 db or higher, I get more carrier power on AM at the expense of excessive SSB power. I guess it needs the power gain (Tx VCE) setting to be per mode, not SSB and AM. 73 Dave, G4AON Lennart Michaëlsson wrote: > GM all, > not that I am one of those AM guys but just checked my K3 which produces 45W > on 160 and 40W on 80. > Maybe some set up trouble, Dave? > 73 > Len > SM7BIC > > _______________________________________________ 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 |
|
Administrator
|
In reply to this post by Dave, G4AON
We measured very close to 25 W here, but I'll look into it.
tnx Wayne On Oct 25, 2008, at 12:51 AM, Dave G4AON wrote: > Wayne, the AM power level in this version only seems to produce a > carrier of 10 Watts when the requested power is "100W". While I don't > agree with the idea of calling the power anything other than the > carrier level, i.e. I would expect the power control to only go to > about 30 Watts on AM, 10 Watts is only 1/3rd of the carrier power a > 100 W nominal transceiver should produce. > > Back to the drawing board? > > 73 Dave, G4AON > K3/100 #80 > ========================================== > > * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation > percentage. > > > > --- 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 |
RE: K3 Beta firmware rev. 2.57
|
|
It measures very close here as well. Even though the power calibrations had been done previously (this was the factory built s/n 622), I did need to do the wattmeter and power level calibrations again at both 5 and 50 watts before the AM carrier power was within the 22-25 watt range across the spectrum. Without the recalibration I saw 30 watts on 160, 25 on 20 and 45 on 10 meters. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of wayne burdick > Sent: Saturday, October 25, 2008 11:40 AM > To: Dave G4AON > Cc: [hidden email] > Subject: Re: [Elecraft] K3 Beta firmware rev. 2.57 > > > We measured very close to 25 W here, but I'll look into it. > > tnx > Wayne > > On Oct 25, 2008, at 12:51 AM, Dave G4AON wrote: > > > Wayne, the AM power level in this version only seems to produce a > > carrier of 10 Watts when the requested power is "100W". > While I don't > > agree with the idea of calling the power anything other than the > > carrier level, i.e. I would expect the power control to only go to > > about 30 Watts on AM, 10 Watts is only 1/3rd of the carrier power a > > 100 W nominal transceiver should produce. > > > > Back to the drawing board? > > > > 73 Dave, G4AON > > K3/100 #80 > > ========================================== > > > > * MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher > modulation > > percentage. > > > > > > > > > > --- > > 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 |
|
Administrator
|
Dave just pointed out that his TXG VCE menu entry (voice gain relative
to CW) was set to -1.5 dB. This menu entry should probably apply only to SSB modes. I'll review this with our DSP engineer. 73, Wayne N6KR Joe Subich, W4TV wrote: > It measures very close here as well. >>> Wayne, the AM power level in this version only seems to produce a >>> carrier of 10 Watts when the requested power is "100W". --- 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 |
RE: Re: K3 Beta firmware rev. 2.57
|
|
> Dave just pointed out that his TXG VCE menu entry (voice gain > relative to CW) was set to -1.5 dB. I just spent the time to check my other K3 ... its AM power is also in the 22-25 watt range across HF (20 Watts on 6M). I have TXG VCE set to +1 dB on s/n 622 (factory assembled) and +0.5 dB on s/n 1450 (kit). TXG VCE is set to make the PEP output on SSB as measured on an LP-100 the same as the CW power measured on the same meter. If I reset TXG VCE to 0.0 dB, the AM carrier power drops 2 to 3 watts depending on the radio and the SSB PEP is 10 to 15 watts low. > This menu entry should probably apply only > to SSB modes. I'll review this with our DSP engineer. I don't know ... it seems to work properly here. If you elect to not make it global, it may be necessary to provide separate TXG settings for voice (SSB), AM and AFSK A/DATA A (DTA) ... or at least SSB/Data and AM. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of wayne burdick > Sent: Saturday, October 25, 2008 12:21 PM > To: [hidden email] > Cc: [hidden email]; 'Dave G4AON' > Subject: [Elecraft] Re: K3 Beta firmware rev. 2.57 > > > Dave just pointed out that his TXG VCE menu entry (voice gain > relative > to CW) was set to -1.5 dB. This menu entry should probably apply only > to SSB modes. I'll review this with our DSP engineer. > > 73, > Wayne > N6KR > > Joe Subich, W4TV wrote: > > > It measures very close here as well. > > >>> Wayne, the AM power level in this version only seems to produce a > >>> carrier of 10 Watts when the requested power is "100W". > > > --- > > 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 |
RE: Re: K3 Beta firmware rev. 2.57
|
|
Perhaps I'm just being dim, but why is TXG necessary at all? Why can't you just turn the mic gain up until you have plenty of drive, and then use the power control to set the output power using the ALC? That's all I recall having to do on other radios.
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 |
RE: Re: K3 Beta firmware rev. 2.57
|
|
> Perhaps I'm just being dim, but why is TXG necessary at all? > Why can't you just turn the mic gain up until you have plenty > of drive, and then use the power control to set the output > power using the ALC? Traditional ALC operates by overdriving the final amplifier. It senses grid current Which is an indication of overdrive and uses that to turn down the drive. Previous generations of solid state radios turned to sensing output power for the level reference. However, those "after the fact" ALC circuits have two serious issues ... first overdrive must have already occurred to generate an ALC signal and overshoot is certain but there is also no protection against overdrive and distortion in the low level intermediate stages. The K3 generates its ALC in the early stages (the DSP) using a feed forward technique that delays the RF to allow the control signal proper effect. By controlling the level early in the transmission chain, the K3 ALC prevents overshoot, protects against distortion due to RF compression or clipping after the "masking filter" or "channel filter" and eliminates distortion due to ALC "hunting" (the effects of ALC constantly overcorrecting then under correcting). Instead of using a short ALC time-constant (which causes the "hunting" distortion in conventional designs), the K3's power level control can almost have a fixed gain with only a slow time constant for fine adjustment. However, since the power control really sets the average power (e.g. CW), there must be some compensation for differences in the peak to average power ratios of various voices, the level of compression/clipping in use and different modulation types (particularly some data modes with very high peak to average ratios) so that operations with minimal clipping or modes with high peak to average power ratios do not overdrive the driver and PA on peaks even though the "average" power is well below the level that has been set. > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Julian, G4ILO > Sent: Saturday, October 25, 2008 6:17 PM > To: [hidden email] > Subject: RE: Re: [Elecraft] K3 Beta firmware rev. 2.57 > > > > > > Joe Subich, W4TV-3 wrote: > > > > > > I don't know ... it seems to work properly here. If you elect > > to not make it global, it may be necessary to provide separate > > TXG settings for voice (SSB), AM and AFSK A/DATA A (DTA) ... or > > at least SSB/Data and AM. > > > > > Perhaps I'm just being dim, but why is TXG necessary at all? > Why can't you just turn the mic gain up until you have plenty > of drive, and then use the power control to set the output > power using the ALC? That's all I recall having to do on other radios. > > ----- > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack > http://www.ham-directory.com/ Ham > Directory http://www.g4ilo.com/kcomm.html KComm for > Elecraft K2 and K3 > -- > View this message in context: > http://n2.nabble.com/Re%3A-K3-Beta-firmware-rev.-2.57-tp137495 Sent from the Elecraft mailing list archive at Nabble.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 |
RE: Re: K3 Beta firmware rev. 2.57
|
|
Thank you for the excellent explanation, Joe. If that's the case, how does someone who does not have a peak reading wattmeter set up the gain so that the PEP output is equal to the amount of power set on the power control? I can feed a sine wave in and adjust the gain so that the RMS output is correct. But if I understand you correctly, the actual peak output will be dependent on the peak to mean ratio of the signal being fed in, so the only way to set the peak power on any mode that modulates the amplitude of the carrier is to calibrate TXG VCE using a scope or a meter that can tell you accurately what the peak power is? In fact, if the power control is really setting the average power, then if I turn off the compressor because I'm talking to someone who is already getting me S9, won't the effect of the slow time constant ALC then be to increase the gain to bring the average power level (and consequently the peak power level) up, because the peak to mean ratio with compressor off will be greater than when it is on?
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 |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |