Monitoring help request

[MM5AHO/]

I'm suffering interference from Virgin Radio's 1215 transmission from Westerglen. (I don't have any trouble with the other transmissions from that site). I can get harmonics and/or sprogs on all these frequencies....
1618, 1674, 1799, 1850, 2025, 2124, 2303, 2430, 3241, 3340, 3393, 3519, 3644, 4860.
Worst for me is 3646 in the 80m band, a harmonic possibly.
I have installed a highpass filter that rolls off at 1800 kHz (giving 40-50dB attenuation at 1215), but while that all but kills 1215, I still get 3646 at S9+40dB
(Incidently the ICE filter I'm using, the 402X is a good buy, works very impressively, and improves StoN ratio in 160 and 80m markedly. I must have been suffering fundamental overload a bit anyway)

I've had some email correspondence with Virgin engineers who ask if I can get any corroboration of the problem. Can you help me?

If you are quite close to Westerglen, then can you listen to any (all?) of the above and let me know if you hear Virgin's AM signal there. And in reporting the outcome can you advise the receiver and antenna used, as well as approximate location.

I can hear these sprogs on both my IC756P3 and FT857, both connected to an 80m 1/4 wave vertical. I'm virtually line of sight to Westerglen, and perhaps 3-4 miles direct.

[GM1BSG]

Geoff

I don't here a sausage of broadcast here in Stirling (at home anyway).

If I manage to get to club tommorrow morning I will have a quick listen also.

1618 Noise just above the floor, sound part digital, some very faint voice, no idents
1674 Nothing, just noise floor, occasional chirp *
1799 Digital mush 1796~1800 Noise just above the floor
1850 Nothing heard. But Occasional voice S4 on SSB (not sure of language but perfectly readable)
2025 Digital mush 2024~2028 Noise just above the floor
2124 Sprog 2122~2125 S4
2303 Nothing
2430 Nothing
3241 Nothing
3340 Nothing
3393 Sprog just above noise floor
3519 Nothing
3644 Nothing
4860 Nothing

Thats on my 756 pII, no bandpass filters, LSB, 1.8k, Preamp2 on, 80M+ long wire ran sloped at beginning for about 15~20m and then horizontal along fence and wall to the back of the house.

Plenty of other noise but not on those frequencies or close and I don't expect that long wire to have that big a rejection from vertically polarised signals.

Plenty of readable and clear CW and voice on 160 and 80.

If I take the antenna and dump it right into the spectrum analyser it shows no nasty peaks at those frequencies and the multiples you see on the sprogs don't add up to harmonics from the 1215 carrier (but would need to know source and LO which generate the 1215 to rule out leakage)

I think some of those frequencies are red herrings Geoff.

I get a hasty intermittent chirp locally here (I reckon its from the array at the services at Bannockburn) which I can here from 1.5~nearly 800MHz. shuts offg around 11.00 pm

I am only really another 9 miles down the road from you (less than 1/2 mile from the services)

BR, John

[mm5aho]

John
thanks for your efforts.
Many of the frequencies on which I can hear some part of Virgin are prabably mixing products with the other transmitters on the site or some other stuff. Its really only 3645 that I'm mostly concerned about (harmonic) being in the 80m band.
Of course it still could be that I have a receiver problem, though seems strange to have it in 2 Rxs.

Will be grateful to hear from anyone else if they can hear something?

Geoff

[mm5aho]

Well, I'm happy to report that the problem appears solved.

Several emails with Virgin Radio promised investigation, though they don't report making any changes or alterations, but monitoring on 31/12 showed the various sprogs gone. (They had been there for several months).

I didn't change anything at my end, so assume that someone did something at their end.

It seems that the unintended signals could only be heard withing a couple of miles of the Tx site, and no further according to the several reports that I got.

Thanks for the help, and HNY to all.

Geoff

[mm5aho]

Unfortunately the problem doesn't appear to be solved as I'd thought.
Its now intermittent, and I was hasty in saying that it had gone.

Problem seems to be associated with two TX on the Westerglen site, and their fundamentals are 1215 (Virgin) and 1090 (Talk).
These two apparently share a common antenna, and are solid state Txs. They have a bank of multiple PAs which combine to give the output signal.

Monitoring by the site engineers including David GM6BIG has shown nothing at the site so far. Using various detection equipment they are monitoring the TX outputs and have so far seen nothing untoward.

Another development is that the various freqs that these sigs can be heard on change from time to time. The audio is slightly distorted, but not so much that it can be identified. Careful listening reveals Virgin with an undertone of Talk 1090.

I've checked two seperate RX at my end to see if this moght be something with my RX, but result is same.

Others have monitored this and some report hearing exactly the same as me, while yet others hear absolutely nothing.
The signal starts and stops too. One night listening to it on 3646, while chatting on 2m to another station in Laurieston, he could not hear it (and he's closer), and was hearing an RTTY stn that I could not hear for the Virgin signal. Suddenly the Virgin sig stopped with me, and up comes the RTTY out of that Virgin noise !!

Next step is to make up a ferrite antenna and see if this can be DF'ed. It could be of course that the emission is not from Westerglen directly, but could be some local device receiving the Westerglen sigs (which of course are very high power), and mixing them with some LO to output at mixing freqs. Such devices as baby alarms, remote control devices etc are potential culprits.

The AFS 80m contest was partly spoiled for me having the Virgin signal on AM at various parts of the spectrum allocated to that contest. Made hearing that bit more difficult.
An intersting problem though, and one that taxes the brain trying to figure out what might be involved in it.
Any comments on what you've heard or not heard appreciated.
Geoff

[gm4vgr]

Geoff
Was talking with MM0RAM GM0KWL & GM6VCV this afternoon David RAM was hearing both 2nd and 3d harmonic from 1090 Brian KWL also gets lots of breakthrough from Westerglen Bill VCV has been listening since the 1950's and says the WX has a lot to do with the breakthrough.In the years gone by people close to Westerglen have been able to pick up signals on various household appliances cookers etc even a pitchfork.
Jim GM4VGR