PMR 446 Mhz

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MajicM
Posts: 19
Joined: Sat Sep 02, 2017 11:40 am

PMR 446 Mhz

Post by MajicM » Wed Jan 31, 2018 7:24 pm

Hi, wondered if someone should shed some light on this for me please?

When I tune the RSP2 to 446 Mhz which is PMR I get this on the waterfall / spectrum:

Image

and I am unable to actually pick anything up. When I put my Uniden 125XLT on the antenna (Discone, Diamond D3000) it always picks up PMR straight away (assuming there are broadcasts, obviously).

I seem to remember with an old RTLSDR dongle I had similar results with SDR Sharp so is it a computer thing? The RSP is well away from the computer and I don't see this kind of interference (or whatever) with anything else.

Thanks for any help!

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mark.
Posts: 51
Joined: Tue Oct 03, 2017 9:14 pm

Re: PMR 446 Mhz

Post by mark. » Thu Feb 01, 2018 1:31 am

Was there a broadcast playing at the time of your snapshot? Do those lines show up under all RF and I.F. gain settings?

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MajicM
Posts: 19
Joined: Sat Sep 02, 2017 11:40 am

Re: PMR 446 Mhz

Post by MajicM » Thu Feb 01, 2018 3:01 pm

No broadcast I was aware of, it appears like that all the time.

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g1hbe
Posts: 494
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire, UK

Re: PMR 446 Mhz

Post by g1hbe » Thu Feb 01, 2018 3:26 pm

That's strange - I find my RSP2 very sensitive on 446 and I hear lots of activity. Those spikes don't look right though - does your USB lead have ferrites on both ends? Try re-arranging your leads to see if you can get rid of that noise. Reduce that 'gain reduction' setting as well, see if signals emerge from the noise floor.

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Andy

MajicM
Posts: 19
Joined: Sat Sep 02, 2017 11:40 am

Re: PMR 446 Mhz

Post by MajicM » Fri Feb 02, 2018 8:40 am

I don't think it does, I'll check. It's never been an issue for anything else.

I can always buy another extender if needs be, it wasn't a cheapie one I know that much.

Ah, so gain could be playing a part here, I'll have a play with that too.

Thanks for the advice :)

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