RadioBanter - View Single Post

December 2nd 03, 07:08 PM

On 2 Dec 2003 09:32:01 -0800, (KC2MAC) wrote:

Radioman wrote in message ...
Front end overload.

It's like trying to see a candle next to a spotlight shining in your face.

Even though they are different freqs? I'm transmitting on 146.400,
but listening on 147.00 (-600k offset).

You may think it's a lot, but 600 kHz to an FM radio can be quite
close.

Is there anything I could do to treat the symptom aside from keeping
the antennas of the two units far apart from each other?

See my other response regarding antenna polarization and duplexers.
You could actually build a simple notch filter out of a piece of coax
and a T fitting. It's not going to be very deep, and it will be wider
(in terms of bandwidth) than a duplexer, but every dB helps in this
case.

I wish I had a spectrum analyzer. I'd love to see definitively what is
happening to the spectrum when I transmit.

Look at any transmitter product review in QST, especially HF gear.
Basically what you will see is a very high spike at the transmit
frequency, with progressively diminishing sidebands for several
hundred Hz either side of the carrier frequency. There will also be
some highly attenuated spikes at periodic intervals above and below
the carrier frequency.

Maybe there is a way I can turn my old oscilloscope into a spectrum
analyzer. hmmmmmmm...

Probably not.

LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

http://www.woodbutcher.net