Bob, Good point. I guess the best way to check the deviation is to put the service monitor in the duplex mode and go from there. I'll have to re-read the book on that.
Our repeater seems to have a "creeping" deviation problem. Tonight was a good illustration of it. We held a net which lasted 23 minutes. At the start of the net, there was no or only slight distortion due to over deviation. At the end of the net, about half of the stations signals when repeated had moderate distortion probably due to higher than normal audio and the exciter modulator knocking the top off the received signals. Why, I don't have the slightest idea. I guess I'll have to run the repeater for 23 minutes to see what happens. Any other theories or ideas? I'm going up the site tomorrow morning, and I want to be armed with the best technical advice on what to look for. 73, Chas, W1CG At 10:26 PM 12/2/2005, you wrote: >As the original post mentioned a service monitor and a >Micor repeater, I just "assumed" that it was the >repeater's deviation that he was interested in. > >Touch-tones are a complex signal formed by two >unrelated audio tones. There's also some inequality in >the levels of the two tones as well as purity of the >signals that will get modified if the level is too >high. The 3-4 kHz deviation on touch-tones is >apppropriate for a mobile or hand-held radio. > >The deviation can be measured with a meter or a scope >only if you're using a constant sine wave as the input >signal. Once you start looking at complex waveforms or >voice, you must use a scope to set the absolute peaks. >The meter will read lower under such conditions. > >The choice of using 400 Hz or 1 kHz is more of a >matter of convenience, however the transmitter's >pre-emphasis will have a bit more effect on the 1 kHz >tone, so you might need less audio for a given amount >of deviation. > >Bob M. >====== >--- mch <[EMAIL PROTECTED]> wrote: > > > TT should be between 3 and 4 kHz deviation. > > (preferably closer to 3) > > > > Joe M. > > > > Charles Greene wrote: > > > > > > Ken, > > > > > > Shouldn't the touch tone pad tone be set at the > > maximum deviation or > > > nearly so? Those are steady and not subject to > > peaks. Also I take > > > it the max deviation should be set with a 1Khz > > audio tone applied> > > > > > > 73, Chas W1CG > > > > > > At 05:05 PM 12/2/2005, you wrote: > > > >One thing that hasn't been mentioned so far, and > > one thing that is quite > > > >important, is that regardless of the suggestion > > of 5 or 4.75 Khz, it must > > > >be noted that these are PEAK values, not average. > > > > > > > >If the average deviation is set for 5 KHz, then > > the peaks will be > > > >absolutely be more than 5 Khz. > > > > > > > >So use the scope in the service monitor, not the > > meter > > > > > > > >Ken > > > >__________________________________ >Start your day with Yahoo! - Make it your home page! >http://www.yahoo.com/r/hs > > > > > >Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
