SSB and MH2
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On the recent topic of SSB audio reports, I got report of "off
frequency" and "too low" on 17M USB today and have not found the problem yet. RIT and XIT were off and 15MhHz WWV was within 5Hz according to my sound card. I did the bandwidth mod while I built my KSB2, following the advice given here, and in the new KSB2 manual -- just about a week before the parts kit was announced. At first I got reports of weak audio, and last night ran through the entire Spectrogram alignment (once on WinXP with my wife's computer, once on Linux under WINE). Now it appears to be better, but there is still something wrong:. This morning I was able to work KH6BB (USSS Missouri, Pearl Harbour, Hawaii) on 18m and got in the first time. Op Lee reported that I was "off frequency" and "too low." Any idea what to check for? The spectrogram plot looked a lot like the one in the paper... _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Leigh, wrote:
I did the bandwidth mod while I built my KSB2, following the advice given here, and in the new KSB2 manual -- This morning I was able to work KH6BB ...Op Lee reported that I was "off frequency" and "too low." Any idea what to check for? The spectrogram plot looked a lot like the one in the paper... ---------------------------------------------------- Leigh, were you receiving on FL1? Filter 1 is always the filter used for transmission, so if you do not have SPLIT, RIT or XIT enabled, you are transmitting on exactly the same frequency you are receiving on when listening on FL1. If you are using a filter other than FL1 you might have as much as a 10 or 20 Hz error if it's set up properly. That's as close as the K2 is capable of resetting the frequency later. That is NOT enough to trigger a "too low" comment, however. It is enough to hear easily when listening to music, but not the human voice. One possibility is that you are simply passing a wider band of frequencies now with the wider filter setting that is making your sound 'different'. I widened the bandwidth of my SSB filter and now keep the low-end cutoff 3-db point at about 400 Hz to avoid the rumble of the "drone" in my voice from hogging the SSB power. I have FL2 set up lower with the cutoff at about 200 Hz because some stations sound better with a little "bass boost". One last point I'll make -- understanding that it is controversial. A lot of people say the Spectrogram puts the filters "right on". I've done it many times and I will agree that it's close, but Spectrogram has never been "right on" in my estimation. It's close enough that most people don't need to do any more, but I've always found it possible to improve the quality by monitoring my signal and making the final adjustments, just as the KSB2 manual advises. I record my signal in an auxiliary receiver and play back the recording to hear how I really sound; bone conduction of sound in your head really changes what you hear if you are listening to yourself in the auxiliary receiver in "real time". If you don't have an auxiliary receiver, get on the air with a buddy who is receiving you well, and try different settings of FL1 until he pronounces you "best". Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Leigh L. Klotz Jr WA5ZNU
Leigh,
As preliminary filter alignment for SSB FL1, I recommend setting 2 markers in Spectrogram - one at 300 Hz and the other at {filter bandwidth + 300 Hz}(- for 2.3 kHz filter use 300 and 2600 Hz). Then adjust the BFO to center the passband between those markers. That will produce a good quality signal for most operators. If your voice is abnormal (or if you just want to further refine things), record your signal on a separate receiver and play it back to evaluate your transmitted audio. Check out the thoughts in Ron D'Eau Clair's post on this subject too. As a totally different thought - could the other operator's evaluation of 'off frequency and too low' be a result of his mistuning? Did you tune so his signal sounded natural, or did you tune to some 'net' frequency? If you tuned to a 'net' frequency, I must ask if you had the tuning rate in the kHz display position - if you did, there may have been hidden digits (other than '.00' in the frequency display and you could have been mistuned for that reason. Be careful not to jump to conclusions on the basis of one bad report - but it is something to review until you find reasonable answers. 73, Don W3FPR ----- Original Message ----- > On the recent topic of SSB audio reports, I got report of "off frequency" > and "too low" on 17M USB today and have not found the problem yet. RIT > and XIT were off and 15MhHz WWV was within 5Hz according to my sound card. > > I did the bandwidth mod while I built my KSB2, following the advice given > here, and in the new KSB2 manual -- just about a week before the parts kit > was announced. At first I got reports of weak audio, and last night ran > through the entire Spectrogram alignment (once on WinXP with my wife's > computer, once on Linux under WINE). Now it appears to be better, but > there is still something wrong:. > > This morning I was able to work KH6BB (USSS Missouri, Pearl Harbour, > Hawaii) on 18m and got in the first time. Op Lee reported that I was "off > frequency" and "too low." Any idea what to check for? The spectrogram > plot looked a lot like the one in the paper... |
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In reply to this post by Leigh L. Klotz Jr WA5ZNU
Low and High on SSB is also in the perception of the listener. If you think
they are on a specific freq. and tune using that then you may be off. I listen to nets where the net control can be off 50-70 Hz and I tune accordingly. Some "lids" think they are right on all the time... :-) Bill K9YEQ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Leigh L Klotz, Jr. Sent: Tuesday, December 28, 2004 9:41 PM To: Elecraft List Subject: [Elecraft] SSB and MH2 On the recent topic of SSB audio reports, I got report of "off frequency" and "too low" on 17M USB today and have not found the problem yet. RIT and XIT were off and 15MhHz WWV was within 5Hz according to my sound card. I did the bandwidth mod while I built my KSB2, following the advice given here, and in the new KSB2 manual -- just about a week before the parts kit was announced. At first I got reports of weak audio, and last night ran through the entire Spectrogram alignment (once on WinXP with my wife's computer, once on Linux under WINE). Now it appears to be better, but there is still something wrong:. This morning I was able to work KH6BB (USSS Missouri, Pearl Harbour, Hawaii) on 18m and got in the first time. Op Lee reported that I was "off frequency" and "too low." Any idea what to check for? The spectrogram plot looked a lot like the one in the paper... _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Ron D'Eau Claire-2
Ron,
I totally agree! "...One last point I'll make -- understanding that it is controversial. A lot of people say the Spectrogram puts the filters "right on". I've done it many times and I will agree that it's close, but Spectrogram has never been "right on" in my estimation. It's close enough that most people don't need to do any more, but I've always found it possible to improve the quality by monitoring my signal and making the final adjustments, just as the KSB2 manual advises...... Bill K9YEQ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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