Re: [Elecraft] K3 FSK power transients
Today I put the old Bird wattmeter in line and found that the average power out of the K3 does *indeed* drop down and become somewhat erratic in fsk441 mode. As noted previously the PEP output stays the same although my watt meter shows some erratic behavior. So my wattmeter is telling the truth. And my K3 has a problem. (I tried different computers and sound cards - all the same). The power fold back is in FSK441 and a similar mode called JTMS. Modes that vary the tone more slowly - JT65 and JT6M - do not cause the same large power drop (minor fluctuations in power only). To use an separate receiver I had to switch from 50 MHz to 28 MHz and there I eventually found that if I run 12 watts (final amp not switched in) then the PEP/Average is quite near 1:1 (or 10:10). Its only when I go to a power level where the final is required, that I get this strange effect. I get quite a high PEP/Average ratio on voice too, but it does not sound bad ... The final still produces plenty of power, so it is not fried. I went through and repeated the transmitter gain calibration - to no effect. So I guess I am going to contact Elecraft on Monday. 73 Ken -Original Message- From: Joe Subich, W4TV [mailto:li...@subich.com] Sent: Friday, May 29, 2015 3:12 PM To: Ken; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 FSK power transients But I stand corrected on the average. I was computing an average of the crest, not the effective value of the wave. Since these are sine waves, the effective value is 0.707 of the crest. Of course, when the crest value is varying over the period under consideration, you might want to average the crests and then multiply by 0.707, which is kind of what I was doing. That is not the definition of peak to average in the RF domain. For a CW (sine wave modulation) signal, the peak to average ratio is 1:1 or 0 dB. Since FSK (specifically, in this case FSK-441 - which is 4FSK) is a sequence of sine waves, the theoretical peak to average ratio is 0 dB. Now, if you introduce AM into the FSK modulation, e.g., some tone or tones have different levels, the crest factor departs from 0 dB. In this case, Peak Power (or PEP) is the maximum average peak (CW) case and average power is the longer term average of the peak power. In a linear system, PEP is the CW (single tone) power while average power - per FCC definition is the value to which a capacitor would charge based on multiple peaks (or the average of the peaks of the modulation). For 4FSK where three of the 4 tones were 1.4 V Peak (1.0 V RMS) while the fourth tone was 1.12V (0.8 V RMS), the average voltage would be: (3 * 1.4 + 1.12)/4 or 1.33 V Peak. The Peak voltage is the highest of the four tones or 1.4 V. Thus the Peak to average ration for a 4FSK signal with one tone at 80% of the other three would 1.4/1.33 - or 0.45 dB. I'd strongly suggest you get an audio oscillator with a known, stable output level, pick one tone - either 1323 or 1764 Hz - and run it into you K3, set the mic gain to 4 bars of ALC and measure the CW output power at that frequency. Then, without changing the audio level or mic gain, measure the CW level of your K3 at 882, 1323, 1764 and 2205 Hz. My guess is that you will find that one tone or another produces significantly less power than the others - probably because of a filter alignment or ripple issue. 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
Joe - I am using data mode with DATA A selected. (This mode uses the SSB filter and turns off equalization and compression. But of course the ALC is on). What would be really helpful is if you would download a copy of Spectrum Lab and run the monitor output of your K3 through it while transmitting FSK441. Then we would both have a common point of comparison (eliminating the vagaries of power meter PEP algorithms). http://www.qsl.net/dl4yhf/spectra1.html The time domain scope is under the components tab. The default settings with the initial install will work fine, although you will have to select your input device (audio card) if it is not the system default. That is under the Options/Audio settings tab. Regards Ken From: Joe Subich, W4TV-4 [via Elecraft] [mailto:ml-node+s365791n760359...@n2.nabble.com] Sent: Thursday, May 28, 2015 10:27 PM To: Ken_ke2n Subject: Re: K3 FSK power transients Are you using DATA A or trying to force FSK-442 through the K3 in USB with the TX_EQ enabled? Again, I see *NO* frequency effects (crest factor 0.1 dB at 30, 60 and 100 W) with my K3 when using DATA A and the LINE In. Also make sure your sound card does not have any enhancements enabled. 73, ... Joe, W4TV On 2015-05-28 9:53 PM, Ken_ke2n via Elecraft wrote: 2015-05-27_20_48_16-Time_domain_scope_no_radio.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_20_48_16-Time _domain_scope_no_radio.gif 2015-05-27_19_07_20-Time_domain_scope.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_19_07_20-Time _domain_scope.gif I hope this works. I have shown, in two attached images, the tones being produced by WSJT FSK441 and then the monitor output of the K3. You can see a substantial drop off of the low frequency tones and some kind of additional modulation of the overall envelope (most noticeable with the higher frequency tone, but I think it affects all). Not sure if this is ALC action or something else. Anyway, the K3 makes a bit of a mess out of some otherwise nice-looking tones. Ken - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p76035 96.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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] _ If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p76035 99.html To unsubscribe from K3 FSK power transients, click here http://elecraft.365791.n2.nabble.com/template/NamlServlet.jtp?macro=unsubsc ribe_by_codenode=3712691code=a2UybkBjcy5jb218MzcxMjY5MXwzMzYyNjM0NzE= . http://elecraft.365791.n2.nabble.com/template/NamlServlet.jtp?macro=macro_v iewerid=instant_html%21nabble%3Aemail.namlbase=nabble.naml.namespaces.Basi cNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template .NodeNamespacebreadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_ emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml NAML - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p7603604.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
A quick reply since I'm on my way out ... I'll look more in depth later. I am concerned about the audio waveform generated by your WaveNode device. I see peaks to 128 +/- and dips to 64 +/- with a significant amount of asymmetry. The asymmetry would make me wonder if there is not some clipping (bad transistor) in the LPA, KPA3 or in the WaveNode device itself. Perhaps the only way to know for sure would be to use a second receiver and look at the *recovered* audio. Mine is using the more steep-sided 8 pole filter and has the new synthesizer board and the latest firmware updates. I'm also using the 2.8 KHz filter, new synthesizer and most recent production firmware for the KSYN3A. Note there was no change in DSP code to support the KSYN3A so I would not expect the firmware to be an issue. PEP/average (power) ratio is the (voltage) crest factor squared. It is hard to get the effective(average) value of the wave by eyeball. But you could take the min/max and divide by 2. No - Crest factor is 10*log(Peak/Average) in terms of power and 20*log(Peak/Average) in terms of voltage. Since the modulation is single sine waves (not a complex waveform) the average (RMS) is 0.7 x peak. The lowest voltage I see is 0.8V, the highest is slightly less than 1.0 (call it 0.98). Using the average of 0.98 and 0.80 (there should be about as many of each tone) we get 20Log(.98/.89) or 0.84 dB which is a reasonable match to the Peak to Average ratio reported by the LP-100. I tried backing down the line level to where no ALC action was visible but there are still dips. Can't do that. With less than 4 bars of ALC the DSP code will try to follow level and may make things worse depending on the time constant. 73, ... Joe, W4TV On 2015-05-29 10:04 AM, Ken wrote: Good job Joe. My understanding is that the monitor output of the K3 should be a fair representation of what another receiver would see - minus the effects of propagation and any external power amplifier. But it is just really something convenient to use (as evidenced by the quickness of your response). From a subjective/eyeball view of the waveform - we can see your K3 is doing a better job than mine. I wonder what the differences are? Mine is using the more steep-sided 8 pole filter and has the new synthesizer board and the latest firmware updates. PEP/average (power) ratio is the (voltage) crest factor squared. It is hard to get the effective(average) value of the wave by eyeball. But you could take the min/max and divide by 2. On your graph, the max is 1.0 and I see two points where it dips to about 0.75 (at 0.5 ms and 11.5 ms). That gives a crest factor of 1.14 and a PEP/average power ratio of 1.3. In decibels that is 2.28 dB which is similar to what a filter passband ripple might be. Anyway, it's better that what I am seeing. Some other artifacts are visible on the 2 kHz segments. For example, at 2 ms there is a cycle that is shorter than the cycles on either side; at about 11.5 ms there is a cycle that is taller than the ones on either side. Some of this is probably in the actual signal as generated. Looking back at my no-radio graph I can see a small fluctuation in the level of a 2 kHz segment where there are 9 cycles in a row... In terms of RF sample, my power meter provides a scope function right off the RF detector. I have included two pictures of this. These are several overlaid scans snatched from a CQ message. The power readings of my wattmeter must come from squaring this voltage measurement. It has pretty high frequency response (0.1 ms features can easily be seen - this is a bit much if used for the power meter readings imho). One of the things I tried yesterday was some pre-emphasis using a software sound equalizer on my audio. The tone levels at the monitor output are closer in level, to each other, with the equalizer inserted. But there are still ups and downs in the envelope of monitored waveform. In terms of power, the graph with the equalization on shows fewer upward peaks in the power level (second file attached). I have not tried with the linear amplifier on yet, but it looks like the PEP/Average ratio has been reduced a bit with the equalizer on (from 1.8 to 1.6) so I guess I will keep it. The dips in power are present in both graphs. Perhaps that is inherent in the modulation? I don't know how to measure audio power at the input to the radio if the signal from the sound card does not have these dips, then the radio must be doing it somehow. I tried backing down the line level to where no ALC action was visible but there are still dips. Later Ken -Original Message- From: Joe Subich, W4TV [mailto:li...@subich.com] Sent: Friday, May 29, 2015 8:35 AM To: Ken_ke2n; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 FSK power transients I don't know what a *monitor* output proves since it is *not* an RF sample. However, I have attached a Spectrum Lab Time Domain capture as requested
Re: [Elecraft] K3 FSK power transients
I was going by this definition: http://en.wikipedia.org/wiki/Crest_factor But I stand corrected on the average. I was computing an average of the crest, not the effective value of the wave. Since these are sine waves, the effective value is 0.707 of the crest. Of course, when the crest value is varying over the period under consideration, you might want to average the crests and then multiply by 0.707, which is kind of what I was doing. That means the PAPR (peak to average power ratio) for a sine wave is, by definition, 3 dB. If you have more than one tone present at any moment the PAPR must be higher than 3 dB (see the URL above). But that is not what our fancy power meters measure. These power meters are supposed to measure Peak Envelope Power and average power. With complex waveforms like speech there is no analytical relationship between PEP and average. It depends on the user's voice and the amount of speech processing used. The peaks can easily be 10-20 times the average in an uncompressed voice signal. For FSK441, the modulating wave is mostly pure tones (of a constant amplitude if all goes well) and some minimal keying sidebands due to the 441 baud modulation. So I was thinking there must be some way to calculate PEP/average. The result of a pure tone, in SSB, is a steady carrier and the filtered envelope of that RF is the same as the average power - so RF PEP/average is 1.0. Mind you, the *instantaneous* value of the RF voltage wave will be 1.414 times the RMS value, but the usual definition of PEP says that a steady carrier has PEP equal to average power. And, when I send one of the steady tones, 73 for example, the Wave Node meter reads PEP equal to average (within some tolerance). What happens is that I see the average power reading rise to the PEP. The PEP reading stays the same. I imagine the K3 is riding herd on the peak and keeping it constant (even with no bars showing). Time for lunch here ;-) But I will send a note to the Wave Node guy and see what he says about those peaks and dips. Ken -Original Message- From: Joe Subich, W4TV [mailto:li...@subich.com] Sent: Friday, May 29, 2015 10:50 AM To: Ken; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 FSK power transients A quick reply since I'm on my way out ... I'll look more in depth later. I am concerned about the audio waveform generated by your WaveNode device. I see peaks to 128 +/- and dips to 64 +/- with a significant amount of asymmetry. The asymmetry would make me wonder if there is not some clipping (bad transistor) in the LPA, KPA3 or in the WaveNode device itself. Perhaps the only way to know for sure would be to use a second receiver and look at the *recovered* audio. Mine is using the more steep-sided 8 pole filter and has the new synthesizer board and the latest firmware updates. I'm also using the 2.8 KHz filter, new synthesizer and most recent production firmware for the KSYN3A. Note there was no change in DSP code to support the KSYN3A so I would not expect the firmware to be an issue. PEP/average (power) ratio is the (voltage) crest factor squared. It is hard to get the effective(average) value of the wave by eyeball. But you could take the min/max and divide by 2. No - Crest factor is 10*log(Peak/Average) in terms of power and 20*log(Peak/Average) in terms of voltage. Since the modulation is single sine waves (not a complex waveform) the average (RMS) is 0.7 x peak. The lowest voltage I see is 0.8V, the highest is slightly less than 1.0 (call it 0.98). Using the average of 0.98 and 0.80 (there should be about as many of each tone) we get 20Log(.98/.89) or 0.84 dB which is a reasonable match to the Peak to Average ratio reported by the LP-100. I tried backing down the line level to where no ALC action was visible but there are still dips. Can't do that. With less than 4 bars of ALC the DSP code will try to follow level and may make things worse depending on the time constant. 73, ... Joe, W4TV On 2015-05-29 10:04 AM, Ken wrote: Good job Joe. My understanding is that the monitor output of the K3 should be a fair representation of what another receiver would see - minus the effects of propagation and any external power amplifier. But it is just really something convenient to use (as evidenced by the quickness of your response). From a subjective/eyeball view of the waveform - we can see your K3 is doing a better job than mine. I wonder what the differences are? Mine is using the more steep-sided 8 pole filter and has the new synthesizer board and the latest firmware updates. PEP/average (power) ratio is the (voltage) crest factor squared. It is hard to get the effective(average) value of the wave by eyeball. But you could take the min/max and divide by 2. On your graph, the max is 1.0 and I see two points where it dips to about 0.75 (at 0.5 ms and 11.5 ms). That gives a crest factor
Re: [Elecraft] K3 FSK power transients
Thanks Don - this is, in fact, how I run it: 4-5 bars. I control power with the power control. I follow the directions ;-) I was just surprised to see the ALC working even with no bars showing. My problems is that my FSK441 has a lot of PEP. And apparently it is not supposed to ... 73 Ken -Original Message- From: Don Wilhelm [mailto:w3...@embarqmail.com] Sent: Friday, May 29, 2015 12:09 PM To: Ken; 'Joe Subich, W4TV'; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 FSK power transients Ken, It may be that you are over-analyzing it. Simply increase the audio to produce 4 bars with the 5th bar flickering. On the K3, that is the NO ALC point - the less than 5 bars area of the ALC meter is more or less like a VU meter, and is done that way to allow you to properly adjust the audio level. You must have adequate audio drive to allow the K3 power control to operate correctly. Control the power output with the power knob, not the audio. The K3 is different in this respect from most (or all) the other transceivers on the market. The sage advice of NO ALC offered for those other transceivers does not work for the K3 (and K2 and KX3). Yes, the K3 is 'riding herd' on the power output, and that is in PEP. 73, Don W3FPR On 5/29/2015 11:46 AM, Ken via Elecraft wrote: example, the Wave Node meter reads PEP equal to average (within some tolerance). What happens is that I see the average power reading rise to the PEP. The PEP reading stays the same. I imagine the K3 is riding herd on the peak and keeping it constant (even with no bars showing). __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
Ken, It may be that you are over-analyzing it. Simply increase the audio to produce 4 bars with the 5th bar flickering. On the K3, that is the NO ALC point - the less than 5 bars area of the ALC meter is more or less like a VU meter, and is done that way to allow you to properly adjust the audio level. You must have adequate audio drive to allow the K3 power control to operate correctly. Control the power output with the power knob, not the audio. The K3 is different in this respect from most (or all) the other transceivers on the market. The sage advice of NO ALC offered for those other transceivers does not work for the K3 (and K2 and KX3). Yes, the K3 is 'riding herd' on the power output, and that is in PEP. 73, Don W3FPR On 5/29/2015 11:46 AM, Ken via Elecraft wrote: example, the Wave Node meter reads PEP equal to average (within some tolerance). What happens is that I see the average power reading rise to the PEP. The PEP reading stays the same. I imagine the K3 is riding herd on the peak and keeping it constant (even with no bars showing). __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
I don't know what a *monitor* output proves since it is *not* an RF sample. However, I have attached a Spectrum Lab Time Domain capture as requested. Notice the crest factor is well less than 1 dB. 73, ... Joe, W4TV On 2015-05-29 7:45 AM, Ken_ke2n via Elecraft wrote: Joe - I am using data mode with DATA A selected. (This mode uses the SSB filter and turns off equalization and compression. But of course the ALC is on). What would be really helpful is if you would download a copy of Spectrum Lab and run the monitor output of your K3 through it while transmitting FSK441. Then we would both have a common point of comparison (eliminating the vagaries of power meter PEP algorithms). http://www.qsl.net/dl4yhf/spectra1.html The time domain scope is under the components tab. The default settings with the initial install will work fine, although you will have to select your input device (audio card) if it is not the system default. That is under the Options/Audio settings tab. Regards Ken __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
But I stand corrected on the average. I was computing an average of the crest, not the effective value of the wave. Since these are sine waves, the effective value is 0.707 of the crest. Of course, when the crest value is varying over the period under consideration, you might want to average the crests and then multiply by 0.707, which is kind of what I was doing. That is not the definition of peak to average in the RF domain. For a CW (sine wave modulation) signal, the peak to average ratio is 1:1 or 0 dB. Since FSK (specifically, in this case FSK-441 - which is 4FSK) is a sequence of sine waves, the theoretical peak to average ratio is 0 dB. Now, if you introduce AM into the FSK modulation, e.g., some tone or tones have different levels, the crest factor departs from 0 dB. In this case, Peak Power (or PEP) is the maximum average peak (CW) case and average power is the longer term average of the peak power. In a linear system, PEP is the CW (single tone) power while average power - per FCC definition is the value to which a capacitor would charge based on multiple peaks (or the average of the peaks of the modulation). For 4FSK where three of the 4 tones were 1.4 V Peak (1.0 V RMS) while the fourth tone was 1.12V (0.8 V RMS), the average voltage would be: (3 * 1.4 + 1.12)/4 or 1.33 V Peak. The Peak voltage is the highest of the four tones or 1.4 V. Thus the Peak to average ration for a 4FSK signal with one tone at 80% of the other three would 1.4/1.33 - or 0.45 dB. I'd strongly suggest you get an audio oscillator with a known, stable output level, pick one tone - either 1323 or 1764 Hz - and run it into you K3, set the mic gain to 4 bars of ALC and measure the CW output power at that frequency. Then, without changing the audio level or mic gain, measure the CW level of your K3 at 882, 1323, 1764 and 2205 Hz. My guess is that you will find that one tone or another produces significantly less power than the others - probably because of a filter alignment or ripple issue. 73, ... Joe, W4TV On 2015-05-29 11:46 AM, Ken wrote: I was going by this definition: http://en.wikipedia.org/wiki/Crest_factor But I stand corrected on the average. I was computing an average of the crest, not the effective value of the wave. Since these are sine waves, the effective value is 0.707 of the crest. Of course, when the crest value is varying over the period under consideration, you might want to average the crests and then multiply by 0.707, which is kind of what I was doing. That means the PAPR (peak to average power ratio) for a sine wave is, by definition, 3 dB. If you have more than one tone present at any moment the PAPR must be higher than 3 dB (see the URL above). But that is not what our fancy power meters measure. These power meters are supposed to measure Peak Envelope Power and average power. With complex waveforms like speech there is no analytical relationship between PEP and average. It depends on the user's voice and the amount of speech processing used. The peaks can easily be 10-20 times the average in an uncompressed voice signal. For FSK441, the modulating wave is mostly pure tones (of a constant amplitude if all goes well) and some minimal keying sidebands due to the 441 baud modulation. So I was thinking there must be some way to calculate PEP/average. The result of a pure tone, in SSB, is a steady carrier and the filtered envelope of that RF is the same as the average power - so RF PEP/average is 1.0. Mind you, the *instantaneous* value of the RF voltage wave will be 1.414 times the RMS value, but the usual definition of PEP says that a steady carrier has PEP equal to average power. And, when I send one of the steady tones, 73 for example, the Wave Node meter reads PEP equal to average (within some tolerance). What happens is that I see the average power reading rise to the PEP. The PEP reading stays the same. I imagine the K3 is riding herd on the peak and keeping it constant (even with no bars showing). Time for lunch here ;-) But I will send a note to the Wave Node guy and see what he says about those peaks and dips. Ken -Original Message- From: Joe Subich, W4TV [mailto:li...@subich.com] Sent: Friday, May 29, 2015 10:50 AM To: Ken; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 FSK power transients A quick reply since I'm on my way out ... I'll look more in depth later. I am concerned about the audio waveform generated by your WaveNode device. I see peaks to 128 +/- and dips to 64 +/- with a significant amount of asymmetry. The asymmetry would make me wonder if there is not some clipping (bad transistor) in the LPA, KPA3 or in the WaveNode device itself. Perhaps the only way to know for sure would be to use a second receiver and look at the *recovered* audio. Mine is using the more steep-sided 8 pole filter and has the new synthesizer board and the latest firmware updates. I'm also using the 2.8 KHz filter, new synthesizer and most
Re: [Elecraft] K3 FSK power transients
Are you using DATA A or trying to force FSK-442 through the K3 in USB with the TX_EQ enabled? Again, I see *NO* frequency effects (crest factor 0.1 dB at 30, 60 and 100 W) with my K3 when using DATA A and the LINE In. Also make sure your sound card does not have any enhancements enabled. 73, ... Joe, W4TV On 2015-05-28 9:53 PM, Ken_ke2n via Elecraft wrote: 2015-05-27_20_48_16-Time_domain_scope_no_radio.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_20_48_16-Time_domain_scope_no_radio.gif 2015-05-27_19_07_20-Time_domain_scope.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_19_07_20-Time_domain_scope.gif I hope this works. I have shown, in two attached images, the tones being produced by WSJT FSK441 and then the monitor output of the K3. You can see a substantial drop off of the low frequency tones and some kind of additional modulation of the overall envelope (most noticeable with the higher frequency tone, but I think it affects all). Not sure if this is ALC action or something else. Anyway, the K3 makes a bit of a mess out of some otherwise nice-looking tones. Ken - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p7603596.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 Message delivered to li...@subich.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
What roofing filter is being used for your transmit and have the offsets been set correctly? One issue I saw once was that the filters were mismatched with the filter definitions entered and the guy was actually using an 8 pole 1.8 SSB for transmit which was causing all kinds of problems in data mode. 73, Guy K2AV On Thursday, May 28, 2015, Ken_ke2n via Elecraft elecraft@mailman.qth.net wrote: 2015-05-27_20_48_16-Time_domain_scope_no_radio.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_20_48_16-Time_domain_scope_no_radio.gif 2015-05-27_19_07_20-Time_domain_scope.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_19_07_20-Time_domain_scope.gif I hope this works. I have shown, in two attached images, the tones being produced by WSJT FSK441 and then the monitor output of the K3. You can see a substantial drop off of the low frequency tones and some kind of additional modulation of the overall envelope (most noticeable with the higher frequency tone, but I think it affects all). Not sure if this is ALC action or something else. Anyway, the K3 makes a bit of a mess out of some otherwise nice-looking tones. Ken - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p7603596.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 javascript:; This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k2av@gmail.com javascript:; -- Sent via Gmail Mobile on my iPhone __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
2015-05-27_20_48_16-Time_domain_scope_no_radio.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_20_48_16-Time_domain_scope_no_radio.gif 2015-05-27_19_07_20-Time_domain_scope.gif http://elecraft.365791.n2.nabble.com/file/n7603596/2015-05-27_19_07_20-Time_domain_scope.gif I hope this works. I have shown, in two attached images, the tones being produced by WSJT FSK441 and then the monitor output of the K3. You can see a substantial drop off of the low frequency tones and some kind of additional modulation of the overall envelope (most noticeable with the higher frequency tone, but I think it affects all). Not sure if this is ALC action or something else. Anyway, the K3 makes a bit of a mess out of some otherwise nice-looking tones. Ken - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p7603596.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
yup. I am seeing this on FSK441 and Data A mode. I recently acquired a power meter that shows average and peak power and I am getting getting PEP = 1.8 times average on this data mode. Traced it to the K3 audio response on transmit. I am using the 8 pole SSB filter. It seems the 882 Hz and 1323 Hz tones are down from the other two tones (or the other tones are hot relative to these two, depending on your point of view). When I transmit a single tone (RRR or 73 report for example) the ALC brings things up to full output. When I transmit mixed characters then the ALC sets the output based on the highest tone and the average is down accordingly. It is not the audio card. I looped the audio card output back to the input and the tones are all the same level. - 73 Ken -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FSK-power-transients-tp3712691p7603573.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 FSK power transients
Hi Dave, Have you tried AFSK instead? If so, do you see similar power transients? Depending on what software is generating the tones and assuming the audio level is set properly, it is possible that AFSK might produce a cleaner signal than what you are seeing in FSK. Operationally, they are the same, i.e. all the same features and operating techniques that you use in FSK D can also be used in AFSK A (well, except maybe for using CW paddles to transmit - that doesn't work in AFSK A). Just another idle thought, but I wonder whether the TX Gain calibration would make a difference? When I try FSK I don't see any sign of similar transients, but my power metering might not be able to respond quickly enough to see them if they were there, so that doesn't necessarily mean a lot. 73, Rich VE3KI Dave Hachadorian K6LL wrote: I'm getting my K3's set up for the CQWW DX RTTY, and notice that there is a significant variation in power output whenever the FSK goes from mark to space or space to mark. One of these K3's is driving a high gain tetrode amp, and the amp's screen current is jumping all over the place. The power transient is only at the time of transition. The steady-state power of the mark and space are equal. I've complained about this before, but it seems to be even worse now. I'm using FW rev 3.30. This amplitude modulation has got to be producing some illegal sidebands. Dave Hachadorian, K6LL Yuma, AZ __ 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 FSK power transients
I just noticed some issues like that last weekend when operating the SAC CW contest. All off a sudden when tuning up on 10m a big bang occured in my linear amplifier. Now nothing got hurt it just blew the fuses. This amp used to be driven with 200W and I never ever had any issues before. Of course it could be the amp and I haven´t measured the K3 to confirm if there are any high power spikes due to poor ALC regulation. I was tuning with fast dots from the keyer. Now I was thinking if the TXGain is set too high maybe that could do something? I guess I have to investigate but I simply haven´t had the time. Jim SM2EKM -- Dave Hachadorian wrote: I'm getting my K3's set up for the CQWW DX RTTY, and notice that there is a significant variation in power output whenever the FSK goes from mark to space or space to mark. One of these K3's is driving a high gain tetrode amp, and the amp's screen current is jumping all over the place. The power transient is only at the time of transition. The steady-state power of the mark and space are equal. I've complained about this before, but it seems to be even worse now. I'm using FW rev 3.30. This amplitude modulation has got to be producing some illegal sidebands. Dave Hachadorian, K6LL Yuma, AZ . __ 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
