Re: [Elecraft] K3 Beta firmware rev. 2.82
Graham Kimbell (G3TCT) wrote: > > Julian > Before you do anything drastic like looking for another radio, can I ask a > silly question or 2? > If the output power is flat across the AF spectrum when using ssb mode, > why > doesn't everyone use it rather than DATA-A? > Well the main reason as I said in my post that I sent about the same time you were writing yours is that it is a hassle changing all the EQ, switching the input from MIC to LINE IN and remembering to turn off the compression. Of course some people may work digi all the time and never use a mic, in which case it would be the most sensible option. But I don't want to go through all that when I hear someone on SSB that I would like to call. Plus, many programs know what mode the K3 is in and won't do data if SSB is selected. > And since the output power is apparently so poorly controlled in DATA-A, > (with much higher power than called for) doesn't this actually give higher > rather than lower IMD? > Yes, although as long as the power is below 100W the IMD should still be within acceptable limits. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2331424.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
My MP has those bumps also, and it's full of INRAD's. With only a minor amount of Spectrogram investigation in my K3, I see a 2db variation across the passband in the 2.7 filter. It is easily seen on RX, particularly if one lies about how wide it is to put the DSP out at 4.0 whilst being confined only by the 2.7 roofing filter. Further the 2.7 filters on my 2 RX K3's have nearly identical response, and the order of the bumps reverses perfectly when I go from DATA to DATA REV. Whether that would be more predictable with a 2.8 8 pole filter would depend. I don't own one so cannot comment. (The shape of the two 2.7's are closer than the shapes on the two 1.8's.) Therefore, without TX EQ set only for DATA mode, power will vary up and down depending on the filter when using a fixed segment audio width of the band and letting the PSK program pick the transmit audio tone. I note that me ears cannot detect changes in the mid-passband. What I hear when shifting RX passband is the drop or addition of lows and highs as the passband *skirts* move. This is to enforce that for SSB, the passband ripple cannot be heard. The data mode transmit exposes what the ear cannot hear only because operators apparently look for variability less than half a db. Given the characteristics of some amplifier tubes and the sudden onset of grid saturation and high current, etc, the desire to control power is understandable. Given the circumstances, would seem to be an interesting idea to have a data mode only TX eq that flattens out the filter *and properly flips* for data rev mode. It would remain to be seen, though whether introduction of the equalization does anything negative to transmitted IMD. Approaching it from the other direction, Wayne & Co seem reluctant to embrace any automatic leveling of data mode transmitted power. It would seem on the surface that data is far more predictable than SSB, that a quick attack, slow release and clamped-across-RX-state auto gain adjustment would work well. There may be a lot more to it than that, but this too seems a good idea. 73, Guy. - Original Message - From: "Kok Chen" To: "elecraft list" Sent: Sunday, February 15, 2009 12:31 PM Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > On Feb 15, 2009, at 2/158:58 AM, Guy Olinger, K2AV wrote: > >> Taking the DATA A readings below at face value, the more than 2 db >> bump >> around 1000 Hz is rather startling. I'm not sure what could cause >> that, but >> at least to me that seems to be screaming for an explanation. >> There's an >> old fireman's adage "never go past fire" to keep from being trapped >> by fire >> closing around behind. > > While I agree that a 2 dB bump is really, really bad for us guys who > use frequency-agile digital transmission, this phenomenon is not > restricted to just the K3. > > The FT-1000MP has a similar 3 dB peak when you select PKT (i.e., > AFSK); and, like the K3, the rig is flat when using voice SSB > modes. In the case of the FT-1000MP, it appears to be a > deliberately designed peaking -- the peak is "centered" near the AFSK > tone pair that you have selected to use. > > To see the FT-1000MP's variability, you can look at the following URL > > http://homepage.mac.com/chen/w7ay/cocoaModem/UsersManual/ > UsersManual.html#equalizer > > Scroll below the two control panels and you will see the graphical > display of the variability. (In this program, you enter the measured > power in that second column on the left, and the program splines the > "curve" to produce the power correction that is applied to the > transmitted signal when you "click on the waterfall.") > > 73 > Chen, W7AY > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Julian Before you do anything drastic like looking for another radio, can I ask a silly question or 2? If the output power is flat across the AF spectrum when using ssb mode, why doesn't everyone use it rather than DATA-A? And since the output power is apparently so poorly controlled in DATA-A, (with much higher power than called for) doesn't this actually give higher rather than lower IMD? Graham - Original Message - From: "Julian, G4ILO" To: Sent: Sunday, February 15, 2009 11:14 AM Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > I have just run a set of tests across a range of audio frequencies as did > Joe, KB8AP. The results were almost identical, so I am not going to tabulate > them here. In SSB I adjusted the input level to give sufficient drive and > just enough ALC action to result in a flat output from 600Hz to 2600Hz. > > At the same time I checked the PSK31 IMD level across the spectrum using the > KK7UQ IMD meter. I observed no degradation of IMD resulting from the use of > minimum ALC to control the power to a flat level, compared to using DATA A > mode where there is apparently no ALC feedback at all. Therefore it seems to > me that the solution that has apparently been adopted in DATA A mode for the > purpose of minimizing IMD is in fact producing no useful benefit at all, > while at the same time depriving data users of a meaningful power control. > > I would much prefer the K3 to work the way other radios work, where you can > increase the drive level until the ALC just starts, and then you know that > you are producing the requested power and no more. This is how I believe it > used to work in early versions of the firmware. DATA was just USB with a > different input source option and compression automatically disabled. > > I will concede that the approach adopted by Elecraft is more foolproof in > regard to avoiding IMD, but this is achieved at the cost of a loss of > confidence in knowing the output power. However for me it is just too > unsettling to not know how much power the radio is putting out, particularly > as I wish to operate remotely via the network and can't see for myself the > power output. I have had to give this up for the last few months after I > found myself transmitting nearly 100W when I was intending to use 40W. > > If the majority of other data mode users are happy with the K3 the way it is > and Elecraft can't or won't change it, then it's probably time for me to > look for another radio. > > - > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's > Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 > -- > View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C -DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2329434.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Bob Cunnings wrote: > > I'm not looking for another radio, as I've been doing what seems > obvious (to me) - using USB mode for sound card digital operation, not > DATA A. [snip] > Yes, I can see the logic in that, which is what I had to do with the K2 before the v2 firmware was released. But I ordered the K3 mainly because it promised to be a much superior radio than the K2 for data operation, so to resort to such a workaround would seem like a major step backwards. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2331384.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
> So, neglecting the ~25 W vs 30 W error, it's clear that > something is keeping a tight rein on things in LSB, but > is not doing so in DATA-A. > Presumably, this is the ALC action, which we are told is > minimized in DATA-A mode. It looks like the ALC uses the wattmeter as an input in SSB but not in data mode. I tried the same set of tests and found that the SSB power would increase (or decrease) over the course of 10 seconds or so to bring the power to the set point. That same effect was not present in DATA. This would explain the differences between SSB and DATA and would - depending on the time constants in the ALC circuit - explain some of the IMD effects in SSB (and the recommendation against the use of amplifier ALC). Here are my power measurements in DATA and DATA-R modes. I have the 8-pole filters in both of my K3s but I have not checked the other one to see if there s any difference in "flatness" ... Set: 60 W Measured: 58.2 W (Tune) NOR (USB) REV (LSB) --- 200 0.3 (-22.9)0.1 (-27.6) 400 22.0 (-4.2) 15.2 (-5.8) 600 46.4 (-1.0) 39.2 (-1.7) 800 55.8 (-0.2) 50.5 (-0.6) 1000 57.0 (-0.1) 55.8 (-0.2) 1200 45.9 (-1.0) 49.0 (-0.7) 1400 43.8 (-1.2) 46.5 (-1.0) 1600 52.9 (-0.4) 50.8 (-0.6) 1800 64.5 ( 1.1) 61.5 ( 0.2) 2000 69.0 ( 1.2) 72.0 ( 0.9) 2200 59.0 ( 0.6) 68.2 ( 0.7) 2400 50.0 (-0.7) 63.0 ( 0.3) 2600 48.5 (-0.8) 64.9 ( 0.5) 2800 15.4 (-5.8) 26.5 (-3.4) 3000 0.00.0 A sweep of the filter using K3FilterTools in the receive mode shows very close correlation with the USB power measurements including the broad peak at 1800-2000 Hz, the roughly 7 dB decline from peak to 2800 Hz and the 2 dB slope between 500 and 2000 Hz. The greater than expected roll off below 600 Hz is apparently due to the audio input response. > -Original Message- > From: Joe Planisky [mailto:jp...@jeffnet.org] > Sent: Saturday, February 14, 2009 7:46 PM > To: li...@subich.com > Cc: elecraft list > Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > > Hi Joe, > > > Further, single tone power calibration is only accurate for the > > specific frequency within the IF filter on which the calibration is > > performed. If I calibrate power in CW mode that > calibration point is > > approximately 300 Hz from one "corner" of the 2.8 KHz > filter thanks to > > the way the K3 offsets the filters. > > If I understand you correctly, you're essentially saying that > in DATA- > A (where, according to Elecraft, ALC action is intentionally > minimized > to minimize distortion), we're seeing more of the true shape of the > filter passband. Whereas in a voice mode (USB or LSB, where ALC > action is more pronounced,) the ALC action will tend to make the > filter passband appear flat if the input is a single tone. > > To test this, I used an audio signal generator to input single tones > of various frequencies into my K3 in both LSB and DATA-A > modes. I set > the power control for 30W. Here are my measurements: > > AF input freq. Po-DATA-APo-LSB > TUNE25.7 25.2 > 200 4.6 6.1 > 40027.0 24.8 > 60034.5 24.8 > 80045.6 24.8 > 100053.1 24.8 > 120047.5 24.8 > 140037.8 24.8 > 160032.3 24.8 > 180030.9 24.8 > 200031.9 24.8 > 220034.3 24.8 > 240037.9 24.8 > 260034.9 24.8 > 280013.9 24.8 > 3000 nil nil > > So, neglecting the ~25 W vs 30 W error, it's clear that something is > keeping a tight rein on things in LSB, but is not doing so in > DATA-A. > Presumably, this is the ALC action, which we are told is > minimized in > DATA-A mode. The data also seem to corroborate your statement that > the calibration point is 300 Hz from the filter corner. > > If I'm really wrong about something, please correct me. If I'm NOT > wrong, I think I might finally understand why power output in DATA-A > doesn't seem to track the requested power closely. > > 73 > -- > Joe KB8AP > > On Feb 14, 2009, at 11:36 AM, Joe Subich, W4TV wrote: > > > > > You CAN NOT make those tests at 50 Watts! The power calibration > > circuitry will be constantly changing the internal gain. > If the ATU > > is enabled and/or your dummy load is not flat th
Re: [Elecraft] K3 Beta firmware rev. 2.82
I'm not looking for another radio, as I've been doing what seems obvious (to me) - using USB mode for sound card digital operation, not DATA A. Yes, I forgo the benefit of the management of compression setting and mic selection that comes with using DATA A - but as things stand now one must change TX EQ manually when switching back and forth between SSB and data modes anyway, right? The compromise would be greater if TX EQ settings become available on a per mode basis. Yes, as you state the difference in quality of signal doesn't seem to be significant, my PSK31 signal is uniformly reported as good when in USB mode, just as in DATA A. I set input level for 4-5 bars ALC. Yes, DATA A is a work in progress. Prior to firmware version 2.23 DATA A power control seemed much like that of LSB/USB, but after that version (which introduced the "LSB/USB TRANSMIT EQUALIZATION" change) the behavior of DATA A and LSB/USB diverged. I've observed the DATA A changes that have taken place since, and corresponded with K3 support on this topic a couple of times as the firmware evolved. However, at the moment I simply run with current firmware and use USB for data modes. Yes, I have an external peak reading watt meter in line at all times so I could use DATA A and tweak the power setting as I move around in the waterfall, but it's convenient to be able to set (and confirm) power once and forget it, as I can in CW. Bob NW8L On Sun, Feb 15, 2009 at 4:14 AM, Julian, G4ILO wrote: > If the majority of other data mode users are happy with the K3 the way it is > and Elecraft can't or won't change it, then it's probably time for me to > look for another radio. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
On Feb 15, 2009, at 2/158:58 AM, Guy Olinger, K2AV wrote: > Taking the DATA A readings below at face value, the more than 2 db > bump > around 1000 Hz is rather startling. I'm not sure what could cause > that, but > at least to me that seems to be screaming for an explanation. > There's an > old fireman's adage "never go past fire" to keep from being trapped > by fire > closing around behind. While I agree that a 2 dB bump is really, really bad for us guys who use frequency-agile digital transmission, this phenomenon is not restricted to just the K3. The FT-1000MP has a similar 3 dB peak when you select PKT (i.e., AFSK); and, like the K3, the rig is flat when using voice SSB modes. In the case of the FT-1000MP, it appears to be a deliberately designed peaking -- the peak is "centered" near the AFSK tone pair that you have selected to use. To see the FT-1000MP's variability, you can look at the following URL http://homepage.mac.com/chen/w7ay/cocoaModem/UsersManual/ UsersManual.html#equalizer Scroll below the two control panels and you will see the graphical display of the variability. (In this program, you enter the measured power in that second column on the left, and the program splines the "curve" to produce the power correction that is applied to the transmitted signal when you "click on the waterfall.") 73 Chen, W7AY __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Guy, K2AV wrote: > > Taking the DATA A readings below at face value, the more than 2 db bump > around 1000 Hz is rather startling. I'm not sure what could cause that, > but > at least to me that seems to be screaming for an explanation. There's an > old fireman's adage "never go past fire" to keep from being trapped by > fire > closing around behind. > > Is there any point at discussing any more subtle issues until we know why > there's a 2 db bump in the middle of an expected flat DATA A bandpass? > Everything from test equipment to meters would be in play until ruled out. > I'm glad you asked that because I've been thinking about the same question. I have the 5-pole 2.7KHz filter and I observed the same peaks at 1000Hz and 2400Hz as Joe, who made those measurements. I guess he has the 5-pole filter too. It would be extremely interesting if someone with an 8-pole filter could run the same test and post the results to see whether there is less variation across the passband. I would not be overjoyed to have to splash $125 to solve the problem, but it might be better than the alternatives. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2330557.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Richard Ferch wrote:
>
> It seems as if part of the problem with the power control in DATA A mode
> may
> be that the power calibration appears to be done at an audio frequency
> which
> is sub-optimal for this mode. Ideally, the power calibration would be done
> at the point in the filter bandpass where the transmit filter's
> attenuation
> is least.
>
I agree, this would be an improvement.
> As it happens, there is another anomaly in DATA A which has some
> similarities to the above, although this may be coincidental. The SPOT
> button in other digital modes produces an audio tone at an optimal
> frequency
> (the selected mark tone in AFSK A and FSK D and the transmitted tone in
> PSK
> D), but in DATA A the SPOT button produces a tone at the CW sidetone
> pitch.
> The CW sidetone has nothing to do with DATA A mode, and it is far from the
> optimal point in the filter bandpass in DATA A. Just as it would be better
> to do power calibration at an optimal audio frequency, it would be better
> if
> the SPOT button produced an optimal tone. Good candidates for an optimal
> tone in DATA A would be either the current filter Fc or the default
> ("NORM")
> Fc for DATA A (1500 Hz).
>
I suspect this might actually be a bug. The trouble with DATA A is that the
K3 doesn't know what center frequency the user is using (though it could
possibly guess from the filter SHIFT setting.) Personally I prefer 1KHz
because I like to hear what is going on and I find higher pitched tones
irritating.
-
Julian, G4ILO. K2 #392 K3 #222.
http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's
Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3
--
View this message in context:
http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2330542.html
Sent from the Elecraft mailing list archive at Nabble.com.
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Re: [Elecraft] K3 Beta firmware rev. 2.82
Taking the DATA A readings below at face value, the more than 2 db bump around 1000 Hz is rather startling. I'm not sure what could cause that, but at least to me that seems to be screaming for an explanation. There's an old fireman's adage "never go past fire" to keep from being trapped by fire closing around behind. Is there any point at discussing any more subtle issues until we know why there's a 2 db bump in the middle of an expected flat DATA A bandpass? Everything from test equipment to meters would be in play until ruled out. 73, Guy. - Original Message - From: "Joe Planisky" To: Cc: "elecraft list" Sent: Saturday, February 14, 2009 7:45 PM Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > Hi Joe, > >> Further, single tone power calibration is only accurate for >> the specific frequency within the IF filter on which the >> calibration is performed. If I calibrate power in CW mode >> that calibration point is approximately 300 Hz from one >> "corner" of the 2.8 KHz filter thanks to the way the K3 >> offsets the filters. > > If I understand you correctly, you're essentially saying that in DATA- > A (where, according to Elecraft, ALC action is intentionally minimized > to minimize distortion), we're seeing more of the true shape of the > filter passband. Whereas in a voice mode (USB or LSB, where ALC > action is more pronounced,) the ALC action will tend to make the > filter passband appear flat if the input is a single tone. > > To test this, I used an audio signal generator to input single tones > of various frequencies into my K3 in both LSB and DATA-A modes. I set > the power control for 30W. Here are my measurements: > > AF input freq. Po-DATA-APo-LSB > TUNE25.7 25.2 > 200 4.6 6.1 > 40027.0 24.8 > 60034.5 24.8 > 80045.6 24.8 > 100053.1 24.8 > 120047.5 24.8 > 140037.8 24.8 > 160032.3 24.8 > 180030.9 24.8 > 200031.9 24.8 > 220034.3 24.8 > 240037.9 24.8 > 260034.9 24.8 > 280013.9 24.8 > 3000 nil nil > > So, neglecting the ~25 W vs 30 W error, it's clear that something is > keeping a tight rein on things in LSB, but is not doing so in DATA-A. > Presumably, this is the ALC action, which we are told is minimized in > DATA-A mode. The data also seem to corroborate your statement that > the calibration point is 300 Hz from the filter corner. > > If I'm really wrong about something, please correct me. If I'm NOT > wrong, I think I might finally understand why power output in DATA-A > doesn't seem to track the requested power closely. > > 73 > -- > Joe KB8AP > > On Feb 14, 2009, at 11:36 AM, Joe Subich, W4TV wrote: > >> >> You CAN NOT make those tests at 50 Watts! The power calibration >> circuitry will be constantly changing the internal gain. If >> the ATU is enabled and/or your dummy load is not flat the changes >> invalidate the measurements. >> >> Further, single tone power calibration is only accurate for >> the specific frequency within the IF filter on which the >> calibration is performed. If I calibrate power in CW mode >> that calibration point is approximately 300 Hz from one >> "corner" of the 2.8 KHz filter thanks to the way the K3 >> offsets the filters. When I switch to DATA A, and try to >> test the power level with a 1500 Hz tone, I can see 2 dB more >> power simply because my 2.8 KHz filter has a 4 dB slope across >> the passband and the K3 gain calculation includes compensation >> for the loss at the calibration frequency. If I check the >> power with a 1 KHz tone, the difference may be 3 dB (DATA A >> is USB, CW calibration is LSB so the slope changes direction >> with tone). If I switch to AFSK A (REV to stay with USB) >> and check power with a 2295 Hz (USB Mark) tone, the difference >> may be down to one dB or so. >> >> There are too many uncompensated variables to expect the K3 >> to maintain absolute control over the power output with >> changing antennas, power levels, modes, (relative) frequency >> within the IF passband and possibly even different filters. >> ALC controls the audio level into, and the RF level out of >> the DSP (modulator) process - it is an ALC (automatic LEVEL >> control) NOT an APC (automatic POWER control). >> >> The ALC is an open loo
Re: [Elecraft] K3 Beta firmware rev. 2.82
It seems as if part of the problem with the power control in DATA A mode may
be that the power calibration appears to be done at an audio frequency which
is sub-optimal for this mode. Ideally, the power calibration would be done
at the point in the filter bandpass where the transmit filter's attenuation
is least. If this were the case, the delivered power would be equal to the
requested power at the optimal frequency, and equal or less at other points
in the filter bandpass. Delivered powers exceeding the requested power would
not happen. Lower output powers would be possible, especially towards the
edges of the bandpass, but this is normal and happens with every radio, not
just the K3.
Performing power calibration at the transmit filter's optimal frequency
might be sub-optimal for CW, though, because of the way the filter bandpass
is adjusted during CW. If this is the case, perhaps there should be separate
power calibrations for CW and for data modes.
As it happens, there is another anomaly in DATA A which has some
similarities to the above, although this may be coincidental. The SPOT
button in other digital modes produces an audio tone at an optimal frequency
(the selected mark tone in AFSK A and FSK D and the transmitted tone in PSK
D), but in DATA A the SPOT button produces a tone at the CW sidetone pitch.
The CW sidetone has nothing to do with DATA A mode, and it is far from the
optimal point in the filter bandpass in DATA A. Just as it would be better
to do power calibration at an optimal audio frequency, it would be better if
the SPOT button produced an optimal tone. Good candidates for an optimal
tone in DATA A would be either the current filter Fc or the default ("NORM")
Fc for DATA A (1500 Hz).
73,
Rich VE3KI
K3 #1595
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Re: [Elecraft] K3 Beta firmware rev. 2.82
Ah! I must have been on an exact 5W setting when I did it, then, Joe. Thanks for clearing that up. I still think that as it's a calibration feature, it would make better sense by being protected by the ability to turn it off. I'd really like to hear why a calibration feature sits there awaiting to pounce on the unwary. 73 DaveL G3TJP I said: > So, if I'm tuning up through, say, a Z-Match into a doublet > and power output is set to "around" 5 or 50W and press "Tune" > in order to tweak the Z-Match, the initial (off-tune) complex > impedance the K3 may see could very well cause the K3's output > power to change to 5 or 50W and because of that, power .. Joe replied: Not quite ... If you set the power level to exactly 5.0 or 50 watts and press the Tune button the K3 will recalibrate. If you set the power to 4.9, 5.1, 49 or 51 watts it will not recalibrate. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
I have just run a set of tests across a range of audio frequencies as did Joe, KB8AP. The results were almost identical, so I am not going to tabulate them here. In SSB I adjusted the input level to give sufficient drive and just enough ALC action to result in a flat output from 600Hz to 2600Hz. At the same time I checked the PSK31 IMD level across the spectrum using the KK7UQ IMD meter. I observed no degradation of IMD resulting from the use of minimum ALC to control the power to a flat level, compared to using DATA A mode where there is apparently no ALC feedback at all. Therefore it seems to me that the solution that has apparently been adopted in DATA A mode for the purpose of minimizing IMD is in fact producing no useful benefit at all, while at the same time depriving data users of a meaningful power control. I would much prefer the K3 to work the way other radios work, where you can increase the drive level until the ALC just starts, and then you know that you are producing the requested power and no more. This is how I believe it used to work in early versions of the firmware. DATA was just USB with a different input source option and compression automatically disabled. I will concede that the approach adopted by Elecraft is more foolproof in regard to avoiding IMD, but this is achieved at the cost of a loss of confidence in knowing the output power. However for me it is just too unsettling to not know how much power the radio is putting out, particularly as I wish to operate remotely via the network and can't see for myself the power output. I have had to give this up for the last few months after I found myself transmitting nearly 100W when I was intending to use 40W. If the majority of other data mode users are happy with the K3 the way it is and Elecraft can't or won't change it, then it's probably time for me to look for another radio. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2329434.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Joe Planisky wrote: > > > To test this, I used an audio signal generator to input single tones > of various frequencies into my K3 in both LSB and DATA-A modes. I set > the power control for 30W. Here are my measurements: > > AF input freq. Po-DATA-APo-LSB > TUNE25.7 25.2 > 200 4.6 6.1 > 40027.0 24.8 > 60034.5 24.8 > 80045.6 24.8 > 100053.1 24.8 > 120047.5 24.8 > 140037.8 24.8 > 160032.3 24.8 > 180030.9 24.8 > 200031.9 24.8 > 220034.3 24.8 > 240037.9 24.8 > 260034.9 24.8 > 280013.9 24.8 > 3000 nil nil > > So, neglecting the ~25 W vs 30 W error, it's clear that something is > keeping a tight rein on things in LSB, but is not doing so in DATA-A. > Presumably, this is the ALC action, which we are told is minimized in > DATA-A mode. The data also seem to corroborate your statement that > the calibration point is 300 Hz from the filter corner. > > That amount of variability is alarming. I'm really not happy with it. But to me, that's not a 25W vs 30W error, it's a 30W vs 53W error. Because the output at 1KHz, which is the center frequency I use for PSK31, is 53W when 30W is requested. This is exactly what I am complaining about. If the power output at 1KHz matched the power level requested then I would be a lot happier, though it is quite disappointing to see that the power would be little more than half that level over most of the range that a Digipan user would operate in. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2329220.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Joe Subich, W4TV-4 wrote: > > > To normalize the radio's output power for any valid test you > need to measure the single tone carrier power (e.g., CW). If > you do that (press tune at 50 watts), you will recalibrate. > The recalibration will render any subsequent measurement > incompatible with previous measurements. > > I already stated that I ran the calibration on all bands at 5 and 50W prior to taking these measurements. There was no need to recalibrate when measuring the power on CW and DATA. In any case, the point of measuring the power on SSB was simply to illustrate that the power control works on SSB but not on DATA. > That's not what I'm suggesting at all. I'm saying you can't > make repeatable measurements at 50.0 watts because of the need > to calibrate the power level before undertaking measurements. > Make the measurements at 40 or 60 watts to eliminate the > errors introduced by automatic recalibration. > > OK. I didn't think you were suggesting that. But I did not invoke any automatic recalibration at any point during my tests. > As to understanding of the radio ... anyone who thinks the > ALC should act as an APC has a far distance to go in their > understanding of the radio and those factors that impact > power output. > I don't think that at all. I expect the power control to regulate the output power in the same way as it does for CW, AM, FM and SSB. If I set the power control to 50W and feed in an adequate level of input I expect to get no more than 50W out and preferably no less. How this is achieved is really not my concern. The amount of unpredictability of the output power in data mode at the moment is not acceptable. I can't imagine that this state of affairs would be considered acceptable if it was CW or SSB that was affected. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2329200.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Conclusion must be, never ever use 5.0W or 50W except when calibration is needed. Why cant power calibration be turned off? Then we would not have this "source for trouble". / SM2EKM Joe Subich, W4TV wrote: > >> So, if I'm tuning up through, say, a Z-Match into a doublet >> and power output is set to "around" 5 or 50W and press "Tune" >> in order to tweak the Z-Match, the initial (off-tune) complex >> impedance the K3 may see could very well cause the K3's output >> power to change to 5 or 50W and because of that, power > > Not quite ... If you set the power level to exactly 5.0 or 50 > watts and press the Tune button the K3 will recalibrate. If > you set the power to 4.9, 5.1, 49 or 51 watts it will not > recalibrate. > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
> So, if I'm tuning up through, say, a Z-Match into a doublet > and power output is set to "around" 5 or 50W and press "Tune" > in order to tweak the Z-Match, the initial (off-tune) complex > impedance the K3 may see could very well cause the K3's output > power to change to 5 or 50W and because of that, power Not quite ... If you set the power level to exactly 5.0 or 50 watts and press the Tune button the K3 will recalibrate. If you set the power to 4.9, 5.1, 49 or 51 watts it will not recalibrate. > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of David Lankshear > Sent: Saturday, February 14, 2009 7:56 PM > To: Elecraft@mailman.qth.net > Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > > So, if I'm tuning up through, say, a Z-Match into a doublet > and power output > is set to "around" 5 or 50W and press "Tune" in order to > tweak the Z-Match, > the initial (off-tune) complex impedance the K3 may see could > very well > cause the K3's output power to change to 5 or 50W and because > of that, power > indication would be screwed up without my noticing it? > (Sorry for the long > sentence, but BTDT.) > > Surely, for something that is a calibration feature, it needs to be > protected by an "on/off switch"? It isn't as though this is > a new topic. > I've seen it crop up a number of times in different forms on > this reflector > and have been waiting for the Aptos wizards to make power > calibration a menu > item. Turn it on in the menu, have a few LED winky-blinkys > to warn you're > in Power Cal., do the job then turn it off in the menu. I > suppose there's > some horribly technical reason for not doing it. > > DaveL G3TJP > > Julian said: > > Why on earth not? I think you are confusing the situation with what > > happens when you press TUNE at 50 watts (which I personally > think is a > > disaster that has already happened on many occasions, but that is > > another matter.) > > Joe said: > To normalize the radio's output power for any valid test you > need to measure the single tone carrier power (e.g., CW). If > you do that (press tune at 50 watts), you will recalibrate. > The recalibration will render any subsequent measurement > incompatible with previous measurements. > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
So, if I'm tuning up through, say, a Z-Match into a doublet and power output is set to "around" 5 or 50W and press "Tune" in order to tweak the Z-Match, the initial (off-tune) complex impedance the K3 may see could very well cause the K3's output power to change to 5 or 50W and because of that, power indication would be screwed up without my noticing it? (Sorry for the long sentence, but BTDT.) Surely, for something that is a calibration feature, it needs to be protected by an "on/off switch"? It isn't as though this is a new topic. I've seen it crop up a number of times in different forms on this reflector and have been waiting for the Aptos wizards to make power calibration a menu item. Turn it on in the menu, have a few LED winky-blinkys to warn you're in Power Cal., do the job then turn it off in the menu. I suppose there's some horribly technical reason for not doing it. DaveL G3TJP Julian said: > Why on earth not? I think you are confusing the situation > with what happens when you press TUNE at 50 watts (which I > personally think is a disaster that has already happened > on many occasions, but that is another matter.) Joe said: To normalize the radio's output power for any valid test you need to measure the single tone carrier power (e.g., CW). If you do that (press tune at 50 watts), you will recalibrate. The recalibration will render any subsequent measurement incompatible with previous measurements. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Hi Joe, > Further, single tone power calibration is only accurate for > the specific frequency within the IF filter on which the > calibration is performed. If I calibrate power in CW mode > that calibration point is approximately 300 Hz from one > "corner" of the 2.8 KHz filter thanks to the way the K3 > offsets the filters. If I understand you correctly, you're essentially saying that in DATA- A (where, according to Elecraft, ALC action is intentionally minimized to minimize distortion), we're seeing more of the true shape of the filter passband. Whereas in a voice mode (USB or LSB, where ALC action is more pronounced,) the ALC action will tend to make the filter passband appear flat if the input is a single tone. To test this, I used an audio signal generator to input single tones of various frequencies into my K3 in both LSB and DATA-A modes. I set the power control for 30W. Here are my measurements: AF input freq. Po-DATA-APo-LSB TUNE25.7 25.2 200 4.6 6.1 40027.0 24.8 60034.5 24.8 80045.6 24.8 100053.1 24.8 120047.5 24.8 140037.8 24.8 160032.3 24.8 180030.9 24.8 200031.9 24.8 220034.3 24.8 240037.9 24.8 260034.9 24.8 280013.9 24.8 3000 nil nil So, neglecting the ~25 W vs 30 W error, it's clear that something is keeping a tight rein on things in LSB, but is not doing so in DATA-A. Presumably, this is the ALC action, which we are told is minimized in DATA-A mode. The data also seem to corroborate your statement that the calibration point is 300 Hz from the filter corner. If I'm really wrong about something, please correct me. If I'm NOT wrong, I think I might finally understand why power output in DATA-A doesn't seem to track the requested power closely. 73 -- Joe KB8AP On Feb 14, 2009, at 11:36 AM, Joe Subich, W4TV wrote: > > You CAN NOT make those tests at 50 Watts! The power calibration > circuitry will be constantly changing the internal gain. If > the ATU is enabled and/or your dummy load is not flat the changes > invalidate the measurements. > > Further, single tone power calibration is only accurate for > the specific frequency within the IF filter on which the > calibration is performed. If I calibrate power in CW mode > that calibration point is approximately 300 Hz from one > "corner" of the 2.8 KHz filter thanks to the way the K3 > offsets the filters. When I switch to DATA A, and try to > test the power level with a 1500 Hz tone, I can see 2 dB more > power simply because my 2.8 KHz filter has a 4 dB slope across > the passband and the K3 gain calculation includes compensation > for the loss at the calibration frequency. If I check the > power with a 1 KHz tone, the difference may be 3 dB (DATA A > is USB, CW calibration is LSB so the slope changes direction > with tone). If I switch to AFSK A (REV to stay with USB) > and check power with a 2295 Hz (USB Mark) tone, the difference > may be down to one dB or so. > > There are too many uncompensated variables to expect the K3 > to maintain absolute control over the power output with > changing antennas, power levels, modes, (relative) frequency > within the IF passband and possibly even different filters. > ALC controls the audio level into, and the RF level out of > the DSP (modulator) process - it is an ALC (automatic LEVEL > control) NOT an APC (automatic POWER control). > > The ALC is an open loop system - the loop gain is calibrated > once at the 5 watt level and once at the 50 watt level for > one specific frequency in the IF passband. Once that is > done, ALC simply controls the DSP gain. If you change the > system gain following the DSP, the output power level WILL > CHANGE. I'm sure it would be theoretically possible to > calibrate the system gain from 100 Hz to 2900 Hz offsets > from the carrier (for both the USB and LSB cases) and apply > that mask to the modulation process but does the DSP system > have enough horsepower to do so and is it worthwhile simply > so the operator can avoid the need to check his power level > when changing mode or modulating frequency? > > 73, > > ... Joe, W4TV > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
> Why on earth not? I think you are confusing the situation > with what happens when you press TUNE at 50 watts (which I > personally think is a disaster that has already happened > on many occasions, but that is another matter.) To normalize the radio's output power for any valid test you need to measure the single tone carrier power (e.g., CW). If you do that (press tune at 50 watts), you will recalibrate. The recalibration will render any subsequent measurement incompatible with previous measurements. > If you are suggesting that you cannot use the K3 AT ALL with > the power set to 5o watts then something is deeply wrong, > either with your understanding or with the design of the > radio. That's not what I'm suggesting at all. I'm saying you can't make repeatable measurements at 50.0 watts because of the need to calibrate the power level before undertaking measurements. Make the measurements at 40 or 60 watts to eliminate the errors introduced by automatic recalibration. As to understanding of the radio ... anyone who thinks the ALC should act as an APC has a far distance to go in their understanding of the radio and those factors that impact power output. > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Julian, G4ILO > Sent: Saturday, February 14, 2009 3:44 PM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > > > > Joe Subich, W4TV-4 wrote: > > > > > > You CAN NOT make those tests at 50 Watts! The power calibration > > circuitry will be constantly changing the internal gain. If > > the ATU is enabled and/or your dummy load is not flat the changes > > invalidate the measurements. > > > > Why on earth not? I think you are confusing the situation > with what happens > when you press TUNE at 50 watts (which I personally think is > a disaster that > has already happened on many occasions, but that is another > matter.) If you > are suggesting that you cannot use the K3 AT ALL with the > power set to 50 > watts then something is deeply wrong, either with your > understanding or with > the design of the radio. > > > > > > > Further, single tone power calibration is only accurate for > > the specific frequency within the IF filter on which the > > calibration is performed. If I calibrate power in CW mode > > that calibration point is approximately 300 Hz from one > > "corner" of the 2.8 KHz filter thanks to the way the K3 > > offsets the filters. When I switch to DATA A, and try to > > test the power level with a 1500 Hz tone, I can see 2 dB more > > power simply because my 2.8 KHz filter has a 4 dB slope across > > the passband and the K3 gain calculation includes compensation > > for the loss at the calibration frequency. If I check the > > power with a 1 KHz tone, the difference may be 3 dB (DATA A > > is USB, CW calibration is LSB so the slope changes direction > > with tone). If I switch to AFSK A (REV to stay with USB) > > and check power with a 2295 Hz (USB Mark) tone, the difference > > may be down to one dB or so. > > > > Well I may not be a professional radio engineer but I am not > dumb enough to > try testing with different frequency tones. As stated, I was > testing with > the same tone in SSB and DATA mode. As far as I am aware, the filter > passband on transmit is the same in both modes. Even if not, > this does not > explain why I got 65W on most bands and 20W on 30m, with > exactly the same > input. > > > > > > > There are too many uncompensated variables to expect the K3 > > to maintain absolute control over the power output with > > changing antennas, power levels, modes, (relative) frequency > > within the IF passband and possibly even different filters. > > ALC controls the audio level into, and the RF level out of > > the DSP (modulator) process - it is an ALC (automatic LEVEL > > control) NOT an APC (automatic POWER control). > > > > The ALC is an open loop system - the loop gain is calibrated > > once at the 5 watt level and once at the 50 watt level for > > one specific frequency in the IF passband. Once that is > > done, ALC simply controls the DSP gain. If you change the > > system gain following the DSP, the output power level WILL > > CHANGE. I'm sure it would be theoretically possible to > > calibrate the system gain from 100 Hz to 2900 Hz offsets > > from the carrier (for both the USB and LSB cases) and apply > > that mask to the mo
Re: [Elecraft] K3 Beta firmware rev. 2.82
Joe Subich, W4TV-4 wrote: > > > You CAN NOT make those tests at 50 Watts! The power calibration > circuitry will be constantly changing the internal gain. If > the ATU is enabled and/or your dummy load is not flat the changes > invalidate the measurements. > Why on earth not? I think you are confusing the situation with what happens when you press TUNE at 50 watts (which I personally think is a disaster that has already happened on many occasions, but that is another matter.) If you are suggesting that you cannot use the K3 AT ALL with the power set to 50 watts then something is deeply wrong, either with your understanding or with the design of the radio. > > Further, single tone power calibration is only accurate for > the specific frequency within the IF filter on which the > calibration is performed. If I calibrate power in CW mode > that calibration point is approximately 300 Hz from one > "corner" of the 2.8 KHz filter thanks to the way the K3 > offsets the filters. When I switch to DATA A, and try to > test the power level with a 1500 Hz tone, I can see 2 dB more > power simply because my 2.8 KHz filter has a 4 dB slope across > the passband and the K3 gain calculation includes compensation > for the loss at the calibration frequency. If I check the > power with a 1 KHz tone, the difference may be 3 dB (DATA A > is USB, CW calibration is LSB so the slope changes direction > with tone). If I switch to AFSK A (REV to stay with USB) > and check power with a 2295 Hz (USB Mark) tone, the difference > may be down to one dB or so. > Well I may not be a professional radio engineer but I am not dumb enough to try testing with different frequency tones. As stated, I was testing with the same tone in SSB and DATA mode. As far as I am aware, the filter passband on transmit is the same in both modes. Even if not, this does not explain why I got 65W on most bands and 20W on 30m, with exactly the same input. > > There are too many uncompensated variables to expect the K3 > to maintain absolute control over the power output with > changing antennas, power levels, modes, (relative) frequency > within the IF passband and possibly even different filters. > ALC controls the audio level into, and the RF level out of > the DSP (modulator) process - it is an ALC (automatic LEVEL > control) NOT an APC (automatic POWER control). > > The ALC is an open loop system - the loop gain is calibrated > once at the 5 watt level and once at the 50 watt level for > one specific frequency in the IF passband. Once that is > done, ALC simply controls the DSP gain. If you change the > system gain following the DSP, the output power level WILL > CHANGE. I'm sure it would be theoretically possible to > calibrate the system gain from 100 Hz to 2900 Hz offsets > from the carrier (for both the USB and LSB cases) and apply > that mask to the modulation process but does the DSP system > have enough horsepower to do so and is it worthwhile simply > so the operator can avoid the need to check his power level > when changing mode or modulating frequency? > > Sorry, but I don't see where the system gain comes in to the argument, since I am reporting results with the same frequency tone used at all times. Nor do I see why changing antennas has any relevance to this issue, since I am using a dummy load that is flat to 500MHz for these tests. The K3 is perfectly capable of regulating the power to a level of accuracy that is acceptable to me in SSB mode. All I am asking is that it perform the same task in DATA A, which is just SSB after all. Early versions of the firmware were perfectly capable of doing this. Why am I being treated as if I am demanding the impossible for simply asking for something that can be done and has been done. I really am very, very fed up with the K3 at this point in time. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2327668.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
You CAN NOT make those tests at 50 Watts! The power calibration circuitry will be constantly changing the internal gain. If the ATU is enabled and/or your dummy load is not flat the changes invalidate the measurements. Further, single tone power calibration is only accurate for the specific frequency within the IF filter on which the calibration is performed. If I calibrate power in CW mode that calibration point is approximately 300 Hz from one "corner" of the 2.8 KHz filter thanks to the way the K3 offsets the filters. When I switch to DATA A, and try to test the power level with a 1500 Hz tone, I can see 2 dB more power simply because my 2.8 KHz filter has a 4 dB slope across the passband and the K3 gain calculation includes compensation for the loss at the calibration frequency. If I check the power with a 1 KHz tone, the difference may be 3 dB (DATA A is USB, CW calibration is LSB so the slope changes direction with tone). If I switch to AFSK A (REV to stay with USB) and check power with a 2295 Hz (USB Mark) tone, the difference may be down to one dB or so. There are too many uncompensated variables to expect the K3 to maintain absolute control over the power output with changing antennas, power levels, modes, (relative) frequency within the IF passband and possibly even different filters. ALC controls the audio level into, and the RF level out of the DSP (modulator) process - it is an ALC (automatic LEVEL control) NOT an APC (automatic POWER control). The ALC is an open loop system - the loop gain is calibrated once at the 5 watt level and once at the 50 watt level for one specific frequency in the IF passband. Once that is done, ALC simply controls the DSP gain. If you change the system gain following the DSP, the output power level WILL CHANGE. I'm sure it would be theoretically possible to calibrate the system gain from 100 Hz to 2900 Hz offsets from the carrier (for both the USB and LSB cases) and apply that mask to the modulation process but does the DSP system have enough horsepower to do so and is it worthwhile simply so the operator can avoid the need to check his power level when changing mode or modulating frequency? 73, ... Joe, W4TV > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Julian, G4ILO > Sent: Saturday, February 14, 2009 11:58 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > > > > Steven.Zabarnick wrote: > > > > > > I installed the new beta last and tested the new output > power control. > > I don't see any improvement in PSK31 output power using > DATA A mode. I > > still get nearly twice the output power than I have dialed > in by the > > PWR knob. In the previous firmware, the measure output power in CW > > modes agreed with the > > PWR knob setting, but now the power output in CW is 20-30% > higher than the > > setting. > > > > I will try to redo the transmitter gain calibration to see if this > > helps. > > > > > I have just got round to testing this firmware release. > Before testing the power output in DATA A mode I did a power > calibration. > > It seems to me that there is still something wrong with the > power control in DATA A mode. To make a comparison, I > switched the input for SSB to LINE IN so I could compare the > power output when sending a pure tone in both modes. > > In DATA A the gain seems to have been reduced, and I had to > increase the LINE IN setting. With PWR set to 50W and the > input level set to give a steady 4 bars, I measured 80W on my > power meter. A slight improvement but still not enough. > > In SSB the power output was correctly controlled so that only > 50W output was produced. > > However, after switching between SSB and DATA a few times to > compare the results, and also changing bands, I found that > the output in DATA is not consistent. Currently I am getting > about 65W for 50 selected. At one point on 20m I actually got > 50W. On 30m I am actually getting 20W (yes, 20W) with 50W > selected, absolutely no change to the audio input compared to > the other bands, and 4 bars of ALC showing. > > Back to the drawing board? > > - > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack > http://www.g4ilo.com/blog.html G4ILO's > Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 > -- > View this message in context: > http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvement s-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2326853.html Sent from the Elecraft mailing list archive at Nabble.com. _
Re: [Elecraft] K3 Beta firmware rev. 2.82
I discovered that my cw power issue was due to a bad power supply for my Elecraft W1 wattmeter. My cw power measurement now agrees with the K3 setting. I still see a 50% higher power output in Data A mode than the K3 setting -- this is an improvement over the nearly 100% that I was seeing using previous firmware. These observations agree with what G4ILO is seeing. > >I installed the new beta last and tested the new output power control. >I don't see any improvement in PSK31 output power using DATA A mode. I >still get nearly twice the output power than I have dialed in by the >PWR knob. In the previous firmware, the measure output power in CW >modes agreed with the PWR knob setting, but now the power output in CW >is 20-30% higher than the setting. > > >I will try to redo the transmitter gain calibration to see if this >helps. > >Steve N9SZ > >K3 #1672 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Steven.Zabarnick wrote: > > > I installed the new beta last and tested the new output power control. I > don't see any improvement in PSK31 output power using DATA A mode. I still > get nearly twice the output power than I have dialed in by the PWR knob. > In > the previous firmware, the measure output power in CW modes agreed with > the > PWR knob setting, but now the power output in CW is 20-30% higher than the > setting. > > I will try to redo the transmitter gain calibration to see if this helps. > > I have just got round to testing this firmware release. Before testing the power output in DATA A mode I did a power calibration. It seems to me that there is still something wrong with the power control in DATA A mode. To make a comparison, I switched the input for SSB to LINE IN so I could compare the power output when sending a pure tone in both modes. In DATA A the gain seems to have been reduced, and I had to increase the LINE IN setting. With PWR set to 50W and the input level set to give a steady 4 bars, I measured 80W on my power meter. A slight improvement but still not enough. In SSB the power output was correctly controlled so that only 50W output was produced. However, after switching between SSB and DATA a few times to compare the results, and also changing bands, I found that the output in DATA is not consistent. Currently I am getting about 65W for 50 selected. At one point on 20m I actually got 50W. On 30m I am actually getting 20W (yes, 20W) with 50W selected, absolutely no change to the audio input compared to the other bands, and 4 bars of ALC showing. Back to the drawing board? - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.g4ilo.com/blog.html G4ILO's Bloghttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Beta-firmware-rev.-2.80%3A-Improvements-to-AFSK-A%2C-DATA-A%2C-SSB%2C-AM%2C-FM%2C-DVR-tp2305650p2326853.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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
I don't see a problem with CW on my K3 (29.4W measured, 30W requested,) but there are definitely still problems with excessive power output in DATA-A. DATA-A initially output the correct power, but after switching to AFSK-A and back to DATA-A, I get well over 2x the requested power out (71W measured vs 30W requested.) 73 -- Joe KB8AP On Feb 11, 2009, at 6:16 AM, steven.zabarn...@notes.udayton.edu wrote: > > I installed the new beta last and tested the new output power > control. I > don't see any improvement in PSK31 output power using DATA A mode. I > still > get nearly twice the output power than I have dialed in by the PWR > knob. In > the previous firmware, the measure output power in CW modes agreed > with the > PWR knob setting, but now the power output in CW is 20-30% higher > than the > setting. > > I will try to redo the transmitter gain calibration to see if this > helps. > > Steve N9SZ > K3 #1672 > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
On Wed, 11 Feb 2009 09:16:45 -0500, you wrote: > >I installed the new beta last and tested the new output power control. I >don't see any improvement in PSK31 output power using DATA A mode. I still >get nearly twice the output power than I have dialed in by the PWR knob. In >the previous firmware, the measure output power in CW modes agreed with the >PWR knob setting, but now the power output in CW is 20-30% higher than the >setting. > >I will try to redo the transmitter gain calibration to see if this helps. > >Steve N9SZ >K3 #1672 I too installed the 1.82 last night. I have no power output problems after making the install, but then, I didn't have any to begin with. Tom, N5GE http://www.n5ge.com http://www.swotrc.net K3 #806 XV144 XV432 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
Hi Steve, Seems to work correctly here even if I exceed the recommended 5 bars of ALC. 73 Doug N3QW - Original Message - From: To: Sent: Wednesday, February 11, 2009 9:16 AM Subject: Re: [Elecraft] K3 Beta firmware rev. 2.82 > > I installed the new beta last and tested the new output power control. I > don't see any improvement in PSK31 output power using DATA A mode. I still > get nearly twice the output power than I have dialed in by the PWR knob. > In > the previous firmware, the measure output power in CW modes agreed with > the > PWR knob setting, but now the power output in CW is 20-30% higher than the > setting. > > I will try to redo the transmitter gain calibration to see if this helps. > > Steve N9SZ > K3 #1672 > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 Beta firmware rev. 2.82
I installed the new beta last and tested the new output power control. I don't see any improvement in PSK31 output power using DATA A mode. I still get nearly twice the output power than I have dialed in by the PWR knob. In the previous firmware, the measure output power in CW modes agreed with the PWR knob setting, but now the power output in CW is 20-30% higher than the setting. I will try to redo the transmitter gain calibration to see if this helps. Steve N9SZ K3 #1672 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
