duffyfamily@xtra.co.nz wrote:
> Hi Guys [or ladies as the case may be] I've been operating my station
> for almost as long as there has been LPFM [some 11 years]with no probs.
> My prob now however is that at certain times of the day [mostly 6:00am
> through to about 10:00am] I am getting totaly blocked by a nasty, noisy
> carrier signal that is very wide band, 87.5Mhz through to 89.2Mhz.
> I have some basic test gear so have checked the radiator, SWR 1.125 and
> TX output, all good but can only get about 50 metres from home before my
> signal drops out [and thats in the car. My normal range is around 3 Km].
> I'm starting to think that it is deliberate [paranioa] but as I live in
> a small rural town just can't think what would be gained except to stop
> listeners tuning in at breakfast time?
>
> I don't wish to go whineing to MED so any suggestions on how to track it
> down with limited equipment would be helpful.
>
> Thanks
>
> Maurice
> CPRfm

First check that the noise doesn't go away when you switch off your transmitter.

Next go driving and walking with a portable radio.

Try seeing if you can shield the antenna with your body.

If your radio doesn't have a signal strength meter you could try putting a
meter on the AGC line.

Next is to go travelling with a directional antenna. Often you get a more
accurate bearing by using then sharp dip on the side of the antenna than the
broad frontal lobe.

Then you could use two identical whips and a simple pin diode switch driven by
an oscillator to rapidly switch between them.

Key search terms include "Radio Direction Finding", ARDF, doppler.