RadioBanter - View Single Post - Effect of Amplitude Modulation on FM reception...

February 17th 04, 01:19 PM

On 17 Feb 2004 04:56:57 GMT, (Avery Fineman)
wrote:

In article , Paul Burridge
writes:

ISTR.......
(through the mists of time) that the excessive bandwidth of an AM
transmission signal can interfere with the reception of a NBFM signal,
though the converse is not true. Can anyone confirm this (or else
flatly deny it/affirm it)?

Paul, you need to be a bit more specific on the above.

Thanks, guys. I think you covered what I wanted to know...

Now I have another question on the same subject. Imagine if you will,
a NBFM recieiver, set to listen on one particular channel. Now
consider 3 seperate sweep transmitters located say 100yds away. Each
sweeps slowly across the band which encompasses the RX's receive
channel.
Sweep transmitter 1 puts out only an unmodulated carrier wave. STX 2
puts out an FM signal of the same power level; STX 3 puts out an AM
signal of the same power. Assume the extent of modulation is likewise
identical - or as identical as it can be given different classes. Now,
which of the three TXs is going to 'take over' the RX channel for the
longest time? IOW, which of the TX signals appears broadest to the FM
RX?

Thanks,

p.
--

The BBC: Licensed at public expense to spread lies.