[BC] Running mono on FM...

[Burt I. Weiner]

Andy,

That's correct, the L-R channel can noise up the audio in weak signal 
conditions.  If you turn off the pilot you will (hopefully) turn off 
the stereo decoder in the receiver.  What I intended to say is that 
if you don't also eliminate the L-R channel, which may not 
necessarily go away if you simply turn the pilot off it can gobble up 
modulation if the generator sees a difference between the left and 
right channels such as an imbalance between the two channels.  You 
really need to turn the generator to mono, not just turning the pilot 
off which can sometimes be available as a test function.

Burt

At 07:57 AM 1/17/2006, you wrote:
> >   Just a word of caution - if you simply turn off the pilot be sure you
> > are not leaving the L-R channel running.  One L.A. station was leaving the
> > L-R on and only feeding mono to the left channel.  The L-R channel was
> > gobbling up modulation.
> >
> > Burt
>
>I don't think this is the case (I seem to recall this being discussed before
>on this list) - Bob Orban or someone else good with the Math may care to
>comment, but correct me of I'm wrong, the major downside to broadcating in
>Stereo is the increased signal to noise ratio that comes with demodulating
>the L-r info - since the noise level increases with frequency in FM the
>penalty is quite high.
>
>Andy Green
>Total Broadcast Consultants Ltd.,
>U8F, City Enterprise Centre,
>Waterford Business Park,
>Cork Road,
>Waterford City,
>Ireland.

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at earthlink.net
K6OQK