Re: [Elecraft] JT65A output power variations
Hello, Many thanks to Julian, Lance, Matt, Richard, Ken, Joe and Lyle for interesting considerations derived from my JT65 output power variations subject! To conclude, DATA A is perfectly usable with VOX: i will migrate to this mode Compression is not recommended: i never use it From my side i will (re)verify the following points: -1- Use of 8poles 2.8kHz for TX -2- TX EQ set to flat -3- Soundcard output level ~ constant (i've done that as 1st searching procedure but to reverify...) TNX one more time and 73, Rudolf PS (OT) Matt, for me, West Coast contacts were done on 14MHz or 18MHz between 15:00 and 18:00 UTC (when conds were good!). For me, when i'm ready at my shack and if conds seems good, i can e-mail to your private address; i'm internet ready with a wireless modem, slow but usable. Matt Zilmer wrote: OK Rudolf or Rudi (for JT65), I don't know what date to suggest for a schedule. If you keep me in mind and let me know what band you'll be on (and when), I'll try to get on the air. I also have not worked HB-land on JT65. I have you in monitoring log at SNR -26, which is workable - or at least it was on that night. :) 73, matt W6NIA K3 #24 K2 #2810 On Wed, 11 Nov 2009 23:57:14 +0100, you wrote: Hi Matt, I enjoy to contact you in JT65 before Winter break! My shack is in a camping site and accessible only during not too cold days (805m over sea level) At home QTH, i work with my old coil loaded mobile Hustler antenna fixed at balcony at 3rd floor with ~30° tilt from vertical position... If i remember, i've never contacted the West coast with this configuration; may be for this Winter??? 73 QRO de Rudi (instead of Rudolf for JT65...), HB9ARI Matt Zilmer wrote: Ken Rudi, I monitored you two working on 20m JT65A a few days ago, when I was getting this computer set up and the levels right (again - new laptop). Any idea how many other K3'ers are into JT65A? 73, matt W6NIA K3 #24 On Wed, 11 Nov 2009 13:10:25 -0800 (PST), you wrote: Rudolf, We have worked many times on JT65A , I also use a K3. I operator in the Data mode , ( setup data mode for USB ) and have had no problem for about a year. I think this is the best way to run data modes. I set the shift at 1250 hz and the BW at 1200 HZ. The JT65 software only looks at 1200 hz bandwidth. This works for me. GL 73 Ken K5DNL -- --- On Wed, 11/11/09, hb9ari hb9...@bluewin.ch wrote: From: hb9ari hb9...@bluewin.ch Subject: Re: [Elecraft] JT65A output power variations. To: Elecraft-forum Elecraft@mailman.qth.net Date: Wednesday, November 11, 2009, 9:59 AM Hello Matt, Yes, TX EQ is flat. I've tried to compensates with TX EQ, but i've all reseted to flat. Thank you for this indication. 73 QRO de Rudolf HB9ARI Matt Zilmer wrote: Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's
[Elecraft] JT65A output power variations.
Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. Many TNX for an answer. 73 QRO de Rudolf, HB9ARI PS With the same sound card and software, using my old FT857 (non D) TX/RX, the output power variation is well under 1dB until the audio band edges. __ 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] JT65A output power variations.
hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain a constant average level when working at different places within the passband. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://n2.nabble.com/JT65A-output-power-variations-tp3985152p3985354.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] JT65A output power variations.
Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain a constant average level when working at different places within the passband. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.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] JT65A output power variations.
Hello Rudolf, I use JT65A all the time with my K3 for 6m EME, and I have always used USB mode for it. I have no trouble with the USB setting...I have never even tried the DATA options. I have the standard 2.7 kHz filter, and set the audio just like I do for USB voice. I make sure to have the ALC fill the 5 bars on the meter, and I use 20 dB of compression to make sure that all the tones come up to the proper power levels. I use the LINE IN on the rear panel for my incoming JT65A tones from the computer. I find the K3 a great rig for JT65A because I can make a flat bandwidth 300 Hz to 2200 Hz, and decode callers over that entire frequency range. I usually run JT65A with the NB on the first setting (IF NAR 1), DSP OFF and the AGC off. It is an amazing mode because it has 10 dB sensitivity over CW. Most of the time on 6m EME, signals are too weak to hear, but they are nicely displayed on the SpecJT screen and decoded on the JT65A screen. Now that we are at the bottom of the sunspot cycle, the ionospheric propagation is very poor. However, because the geomagnetic field is usually very quiet these days, this is the VERY BEST time for 6m EME! That is why there has been so much growth in 6m EME over the last year, and there have been such successful DX operations by small 6m stations using JT65A mode with just a single yagi aimed at the horizon. GL and VY 73, Lance hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. Many TNX for an answer. 73 QRO de Rudolf, HB9ARI PS With the same sound card and software, using my old FT857 (non D) TX/RX, the output power variation is well under 1dB until the audio band edges. __ 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 -- Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX) P.O. Box 73 Frenchtown, MT 59834 USA QTH: DN27UB TEL: (406) 626-5728 URL: http://www.bigskyspaces.com/w7gj 2m DXCC #11/6m DXCC #815 Interested in 6m EME? Ask me about subscribing to the MAGIC BAND EME email reflector! __ 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] JT65A output power variations.
Hello Lance, I use the same settings for ALC(also 5 bars in JT65), USB and use the rear LINE IN. As you are using the original 2.7kHz filter this seems not be the problem.; BUT i don't use compression and this can explain that you don't have my output power variation; i can imagine that 20dB compression should be able to compensates a ~ 3dB HF output variation. In receive, i have no problem. Some time ago, i do a HF output response measurement (with a LP-100) and i remember that the curve was far from flat...As it was before i use JT65, with voice, my correspondents don't hear something wrong. It's only since i use extensively JT65 and monitor my output power according QRP'ers request, HF band, etc that i've remarked this 3dB output variation. For ~ 1000 HF JT65 QSO, i worked from 0.5W to (exceptionally) 300W. My usual power is between 25W and 50W. I think that compression will correct (if necessary..) my problem but the source seems to be from the filter used in TX. Next week-end i should be clear about that. For the moment, i'm not QRV on 6m Terrestrial, MS or EME. Just SSB when apertures are there. Thank you for your explanations and i will try compression; habitually, i don't like too much to use it, but... 73 QRO, Rudolf HB9ARI Lance Collister, W7GJ wrote: Hello Rudolf, I use JT65A all the time with my K3 for 6m EME, and I have always used USB mode for it. I have no trouble with the USB setting...I have never even tried the DATA options. I have the standard 2.7 kHz filter, and set the audio just like I do for USB voice. I make sure to have the ALC fill the 5 bars on the meter, and I use 20 dB of compression to make sure that all the tones come up to the proper power levels. I use the LINE IN on the rear panel for my incoming JT65A tones from the computer. I find the K3 a great rig for JT65A because I can make a flat bandwidth 300 Hz to 2200 Hz, and decode callers over that entire frequency range. I usually run JT65A with the NB on the first setting (IF NAR 1), DSP OFF and the AGC off. It is an amazing mode because it has 10 dB sensitivity over CW. Most of the time on 6m EME, signals are too weak to hear, but they are nicely displayed on the SpecJT screen and decoded on the JT65A screen. Now that we are at the bottom of the sunspot cycle, the ionospheric propagation is very poor. However, because the geomagnetic field is usually very quiet these days, this is the VERY BEST time for 6m EME! That is why there has been so much growth in 6m EME over the last year, and there have been such successful DX operations by small 6m stations using JT65A mode with just a single yagi aimed at the horizon. GL and VY 73, Lance hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. Many TNX for an answer. 73 QRO de Rudolf, HB9ARI PS With the same sound card and software, using my old FT857 (non D) TX/RX, the output power variation is well under 1dB until the audio band edges. __ 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] JT65A output power variations.
Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain a constant average level when working at different places within the passband. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.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 __ 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] JT65A output power variations.
Hello Matt, Yes, TX EQ is flat. I've tried to compensates with TX EQ, but i've all reseted to flat. Thank you for this indication. 73 QRO de Rudolf HB9ARI Matt Zilmer wrote: Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain a constant average level when working at different places within the passband. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.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 __ 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] JT65A output power variations.
I don't understand why anyone would use USB mode to operate a sound card data mode, and have all the bother of switching the input between the mic socket and the back panel, when the K3 provides a data mode with EQ flat and compression off specifically for that purpose. Surely using a digimode set up for SSB with ALC operating and 20dB of compression is going to cause distortion and splatter? Admittedly, JT65A isn't PSK31 but even so I would have thought IMD products would occur, though if you are operating on some VHF band and not the crowded digital sector of 20m perhaps no-one will be bothered? I find my K3 produces more than ample output to drive sound card apps. I am currently using LIN OUT = 10. In fact if I use much higher levels clipping occurs somwhere and I see harmonics on the waterfall spectrum. On transmit the wave and master output sliders of my SB Live 24 card are set to just below half way and the LINE level is currently set to 7. So I cannot explain why you find the K3 line input insensitive or a lack of drive on receive. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://n2.nabble.com/JT65A-output-power-variations-tp3985152p3987366.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] JT65A output power variations.
Julian, G4ILO wrote: Surely using a digimode set up for SSB with ALC operating and 20dB of compression is going to cause distortion and splatter? Admittedly, JT65A isn't PSK31 but even so I would have thought IMD products would occur, Not all digital modes are equal. PSK31 depends on amplitude shaping to preserve its narrow bandwidth. It must be operated with no compression and with the requested power kept low enough to avoid clipping of instantaneous peaks. Some other digital modes such as MT63 are similar. Compression in these modes produces IMD which cannot easily be filtered, since it results in unwanted output at frequencies very close to the intended frequency. The recommended way to operate these modes on the K3 is with no compression, and with 5 bars showing on the K3's ALC meter, which puts the K3's ALC in an area where it acts to keep the time-averaged power at the desired level without clipping instantaneous peaks and causing IMD. However, RTTY and many FSK or MFSK-type modes (including JT65A, I believe) feature a single constant-amplitude carrier that is stepped between tones. When there is only a single tone being transmitted at any time, compression does not cause intermodulation; it causes harmonic distortion (odd-order harmonics), which can be eliminated by filtering (the transmitter's crystal filter). The net effect after both compression and filtering should be a constant amplitude signal. I believe this is why JT65A users can safely use compression. 73, Rich VE3KI __ 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] JT65A output power variations.
Richard Ferch wrote: However, RTTY and many FSK or MFSK-type modes (including JT65A, I believe) feature a single constant-amplitude carrier that is stepped between tones. When there is only a single tone being transmitted at any time, compression does not cause intermodulation; it causes harmonic distortion (odd-order harmonics), which can be eliminated by filtering (the transmitter's crystal filter). The net effect after both compression and filtering should be a constant amplitude signal. I believe this is why JT65A users can safely use compression. Hmm. As I wrote in my blog a while back ( http://www.g4ilo.com/2009/10/embarrassing-moments-in-ham-radio-1.html ) I once inadvertently did an experiment that proved the crystal filtering does not do a perfect job of removing the harmonics of a distorted RTTY signal. And surely the amplitude is not constant as seen by the ALC due to the effect of the ripple. If it was constant the ALC wouldn't change so it would not cause any harmful effects. But heck, I'm just a software guy. Hopefully someone like Lyle who actually knows what he is talking about will chip in on this. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://n2.nabble.com/JT65A-output-power-variations-tp3985152p3988430.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] JT65A output power variations.
Rudolf, We have worked many times on JT65A , I also use a K3. I operator in the Data mode , ( setup data mode for USB ) and have had no problem for about a year. I think this is the best way to run data modes. I set the shift at 1250 hz and the BW at 1200 HZ. The JT65 software only looks at 1200 hz bandwidth. This works for me. GL 73 Ken K5DNL -- --- On Wed, 11/11/09, hb9ari hb9...@bluewin.ch wrote: From: hb9ari hb9...@bluewin.ch Subject: Re: [Elecraft] JT65A output power variations. To: Elecraft-forum Elecraft@mailman.qth.net Date: Wednesday, November 11, 2009, 9:59 AM Hello Matt, Yes, TX EQ is flat. I've tried to compensates with TX EQ, but i've all reseted to flat. Thank you for this indication. 73 QRO de Rudolf HB9ARI Matt Zilmer wrote: Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain a constant average level when working at different places within the passband. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.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 __ 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
Re: [Elecraft] JT65A output power variations.
Julian, G4ILO wrote: Hmm. As I wrote in my blog a while back ( http://www.g4ilo.com/2009/10/embarrassing-moments-in-ham-radio-1.html ) I once inadvertently did an experiment that proved the crystal filtering does not do a perfect job of removing the harmonics of a distorted RTTY signal. If the primary tones fed into the audio input of the radio are accompanied by other unrelated frequencies (e.g. hum and noise), or are laden with harmonics that fall within the filter bandpass (e.g. harmonics of a 500 Hz tone), then a 2.7 kHz transmit filter may not be able to do much about it. That is one reason why many people use high tones for RTTY (2125/2295 Hz), to ensure that even the second harmonics are outside the filter bandpass. When I suggested that single-tone FSK/MFSK signals are not subject to IMD, I was of course oversimplifying. The FSK modulation itself introduces sidebands, and excessive compression can cause IMD that broadens those sidebands. However, the JT65A signaling rate is very low compared to the occupied bandwidth (2.7 Hz vs. 177.6 Hz, if I have understood the documentation correctly), so the effect of IMD is probably not noticeable in most cases. I suspect (without hard evidence, of course) that JT65A is much more forgiving than PSK31, i.e. that producing a splattered JT65A signal is much harder to do than producing a splattered PSK31 signal. RTTY would fall somewhere in between. 73, Rich VE3KI __ 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] JT65A output power variations.
However, RTTY and many FSK or MFSK-type modes (including JT65A, I believe) feature a single constant-amplitude carrier that is stepped between tones. When there is only a single tone being transmitted at any time, compression does not cause intermodulation; it causes harmonic distortion (odd-order harmonics), which can be eliminated by filtering (the transmitter's crystal filter). The net effect after both compression and filtering should be a constant amplitude signal. I believe this is why JT65A users can safely use compression. I would not use compression with ANY FSK mode. Compression will change the system gain which will effect the wave shaping (e.g., raised cosine, Blackman, etc.) applied to the data transitions. Improper wave shaping can result in increased bandwidth (digital key clicks) or even level spikes on the leading/trailing edge of the data transitions. 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Richard Ferch Sent: Wednesday, November 11, 2009 1:58 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] JT65A output power variations. Julian, G4ILO wrote: Surely using a digimode set up for SSB with ALC operating and 20dB of compression is going to cause distortion and splatter? Admittedly, JT65A isn't PSK31 but even so I would have thought IMD products would occur, Not all digital modes are equal. PSK31 depends on amplitude shaping to preserve its narrow bandwidth. It must be operated with no compression and with the requested power kept low enough to avoid clipping of instantaneous peaks. Some other digital modes such as MT63 are similar. Compression in these modes produces IMD which cannot easily be filtered, since it results in unwanted output at frequencies very close to the intended frequency. The recommended way to operate these modes on the K3 is with no compression, and with 5 bars showing on the K3's ALC meter, which puts the K3's ALC in an area where it acts to keep the time-averaged power at the desired level without clipping instantaneous peaks and causing IMD. However, RTTY and many FSK or MFSK-type modes (including JT65A, I believe) feature a single constant-amplitude carrier that is stepped between tones. When there is only a single tone being transmitted at any time, compression does not cause intermodulation; it causes harmonic distortion (odd-order harmonics), which can be eliminated by filtering (the transmitter's crystal filter). The net effect after both compression and filtering should be a constant amplitude signal. I believe this is why JT65A users can safely use compression. 73, Rich VE3KI __ 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] JT65A output power variations.
Hi Julian, I choose USB to be able to use VOX; may be i'm wrong, but with DATA A, the TX activation is only possible with COM or PTT? (it's the case for my old FT857) As i use rarely voice modulation, the front panel I/O receptacles are free, i don't have the necessity of a TX activation with lot of problems like RTS? and/or DSR?, DTR?, etc. The serial K3 is always connected to PC, and sometimes activated at the same time with WSJT and JT65-HF, for other programs like HRD,etc I prefer to use a LINE Input for the K3 to get a better SNR; i get sometimes bad results when using a MIC input level for modulation from sound card... I agree with you to avoid any level of compression and this level is always set to 0 , during my (rare) voice QSO too. I worked before for Broadcast TV and, before digital audio/video transfer, LINE level was always preferred, when possible, to MIC level for audio. One more point for LINE level, is value is +/- well defined, for MIC level, it's an other story... 73 QRO de Rudolf, HB9ARI Julian, G4ILO wrote: I don't understand why anyone would use USB mode to operate a sound card data mode, and have all the bother of switching the input between the mic socket and the back panel, when the K3 provides a data mode with EQ flat and compression off specifically for that purpose. Surely using a digimode set up for SSB with ALC operating and 20dB of compression is going to cause distortion and splatter? Admittedly, JT65A isn't PSK31 but even so I would have thought IMD products would occur, though if you are operating on some VHF band and not the crowded digital sector of 20m perhaps no-one will be bothered? I find my K3 produces more than ample output to drive sound card apps. I am currently using LIN OUT = 10. In fact if I use much higher levels clipping occurs somwhere and I see harmonics on the waterfall spectrum. On transmit the wave and master output sliders of my SB Live 24 card are set to just below half way and the LINE level is currently set to 7. So I cannot explain why you find the K3 line input insensitive or a lack of drive on receive. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.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] JT65A output power variations.
I choose USB to be able to use VOX; may be i'm wrong, but with DATA A, the TX activation is only possible with COM or PTT? VOX works in DATA A. 73, Lyle KK7P __ 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] JT65A output power variations.
Hi Ken, I will look next week-end if DATA mode is usable with VOX? If i remember correctly, this was the (only) reason i choose USB mode(?) As i said before, the 3dB variation with output power in certain circumstances, when DF= ~ 0Hz is only a minor problem; i work with that since March 2008. I was just curious to know the cause of this selective effect with some particular JT65 tones. Just a precision, this level variation is also perfectly perceptible with the MON(itor) output of the K3... Very pleased to meet you in this forum and i enjoy to see you soon in the JT65 windows! (May be before my forced Winter break!) 73 QRO de Rudolf, HB9ARI Ken Roberson wrote: Rudolf, We have worked many times on JT65A , I also use a K3. I operator in the Data mode , ( setup data mode for USB ) and have had no problem for about a year. I think this is the best way to run data modes. I set the shift at 1250 hz and the BW at 1200 HZ. The JT65 software only looks at 1200 hz bandwidth. This works for me. GL 73 Ken K5DNL -- --- On Wed, 11/11/09, hb9ari hb9...@bluewin.ch wrote: From: hb9ari hb9...@bluewin.ch Subject: Re: [Elecraft] JT65A output power variations. To: Elecraft-forum Elecraft@mailman.qth.net Date: Wednesday, November 11, 2009, 9:59 AM Hello Matt, Yes, TX EQ is flat. I've tried to compensates with TX EQ, but i've all reseted to flat. Thank you for this indication. 73 QRO de Rudolf HB9ARI Matt Zilmer wrote: Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level in DATA A to get 5 bars on the ALC scale. This will not prevent the power varying for different tones during a transmission but it should help maintain
Re: [Elecraft] JT65A output power variations.
Hi Matt, I enjoy to contact you in JT65 before Winter break! My shack is in a camping site and accessible only during not too cold days (805m over sea level) At home QTH, i work with my old coil loaded mobile Hustler antenna fixed at balcony at 3rd floor with ~30° tilt from vertical position... If i remember, i've never contacted the West coast with this configuration; may be for this Winter??? 73 QRO de Rudi (instead of Rudolf for JT65...), HB9ARI Matt Zilmer wrote: Ken Rudi, I monitored you two working on 20m JT65A a few days ago, when I was getting this computer set up and the levels right (again - new laptop). Any idea how many other K3'ers are into JT65A? 73, matt W6NIA K3 #24 On Wed, 11 Nov 2009 13:10:25 -0800 (PST), you wrote: Rudolf, We have worked many times on JT65A , I also use a K3. I operator in the Data mode , ( setup data mode for USB ) and have had no problem for about a year. I think this is the best way to run data modes. I set the shift at 1250 hz and the BW at 1200 HZ. The JT65 software only looks at 1200 hz bandwidth. This works for me. GL 73 Ken K5DNL -- --- On Wed, 11/11/09, hb9ari hb9...@bluewin.ch wrote: From: hb9ari hb9...@bluewin.ch Subject: Re: [Elecraft] JT65A output power variations. To: Elecraft-forum Elecraft@mailman.qth.net Date: Wednesday, November 11, 2009, 9:59 AM Hello Matt, Yes, TX EQ is flat. I've tried to compensates with TX EQ, but i've all reseted to flat. Thank you for this indication. 73 QRO de Rudolf HB9ARI Matt Zilmer wrote: Since you're using USB, you might want to be sure you have the TX EQ flat. Or use DATA A, where the EQ doesn't apply. 73, matt W6NIA On Wed, 11 Nov 2009 11:28:36 +0100, you wrote: Hi Julian, Thank you for your fast answer! A 1st point, as with the FT857, i'm using USB mode for JT65A. For the filter used, i ordered a 8 poles 2.8k with my K3, but i'm not sure if the 5 poles 2.7k original and always installed as FIL2 is not selected during TX???; next week-end, when active at my external shack, i will look how to remove the 2.7k filter, as i've also problem with center filter when i adjust the HI LO filter controls; when the 2.7k filter is (automatically) selected, i've a big discontinuity with filter setting. As you say, i will look if the 2.7k is not selected during TX. I read also the problems when in DATA A mode, but as said, i'm working in USB (as recommended for JT65A for all RF bands) and VOX work at perfection too. My best 73, Rudolf HB9ARI PS As i expect to get 50W output when i set the control to 50W, i've adjusted the audio input level for max bars on ALC. For PSK31, i work with ~ 10 to15W max for 100W selectes with the control and local receiving give me an acceptable -24 to -28dB IMD. Julian, G4ILO wrote: hb9ari wrote: Hello, As i use principally JT65A (snice ~ 2years), i've remarked transmit output power variations depending where the audio is located in the waterfall, as i'm not speaking English, it's difficult to explain correctly; if i'm ~ in the middle of the waterfall (~ 1200Hz) i get over 3dB in output power variations; for an expected 50W output power, between some tones of the JT65A modulation, the output level can vary from 20W to 60W; if i'm working away from the middle, variations are lower and acceptable but most of time, central frequencies are used... I've always worked with this problem as i expect some AGC effect by the receiving side... I would appreciate to have an explanation of this effect. This topic has been brought up before in the context of RTTY. The reason is that there is no automatic level control in DATA A mode (or rather, there is, but it is very slow acting to avoid causing IMD on PSK31 signals) so there is no compensation for ripples in the roofing filter passband. It has been suggested that the problem is less when using the 8-pole SSB roofing filter as it has less ripple than the standard 5-pole filter. The output should not vary as much as you suggest while working within the normal passband for JT65A operation so I'm wondering if you have correctly adjusted the audio input level
Re: [Elecraft] JT65A output power variations.
Hi Lyle, Ok Lyle, one more time a too fast reading of (very well written!) K3's manual!!! Have a nice day. 73, Rudolf HB9ARI K3#1212 Lyle Johnson wrote: I choose USB to be able to use VOX; may be i'm wrong, but with DATA A, the TX activation is only possible with COM or PTT? VOX works in DATA A. 73, Lyle KK7P __ 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
