[PPRAANet] Sorry OM Your Not Making the Machine

[W0rw at aol.com]

There is a really good article on eham about FM repeater operation.
See the following article, "Sorry OM Your Not Making the Machine"
http://www.eham.net/articles/5612

FM modulation has some different characteristics than AM modulation:

1. If you talk really loud on an FM transmitter there is a good chance your 
voice energy will go outside of the FM channel and the receiving station will 
hear you clipping or dropping out on voice peaks. Maximum readability and 
maximum range is achieved when the transmitter is correctly modulated and this some 
times means you have to back off of the microphone to communicate. Phase 
distortion caused my mulitpath signals can do the same thing and there maybe no 
solution except moving the antenna.
If the transmitter is adjusted wrong this maybe overdeviation.
If the receiving station has his squelch set too tight it can cause drop outs 
on voice peaks too.

2. If a station has low audio but there is no background static noise when he 
is not talking, then he may just have low deviation, low audio or a bad 
microphone.

3. If you hear voice and static noise at the same volume level as a station 
fades in and out, then he has a weak RF signal and needs to increase power or 
change location.

4. If a station has good audio but you can hear dogs barking, kids screaming 
and road noise in the back ground, His audio gain maybe set too high.
Some radios have a separate audio gain control.
The best audio will be achieved when you talk very close to the microphone 
but not into it.
Always talk across your microphone to prevent 'Puffing' noises from being 
transmitted by your fricatives.

5. Signal reports should be given relative to readability and amount of 
'Quieting"
in your receiver. A Full Quieting signal has no back ground hiss. A 50% 
quieting signal has 50% hiss in the background.
When you are on a repeater you can tell the other station that he is ##% 
quieting into the repeater but if you are not receiving the repeater as full 
quieting, don't add your receive circuit noise to the other stations signal report. 
Just say you can't not 
hear the repeater very well at your location, or that the repeater itself is 
##%
quieting.
Paul  w0rw