1650 carrier + tone

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Brookman Spark
Posts: 90
Joined: 19 Jan 2016 18:15

1650 carrier + tone

Post by Brookman Spark » 16 Apr 2017 14:19

It appeared a few weeks ago and was still there yesterday evening. A check on several remote receivers suggests southern England or northern France. And that in turn suggests it might be Cap Gris Nez maritime trying to keep Netherlands pirates off the frequency - with limited success.

But that's all supposition; anyone got a DF fix on this one?

KPC850
Posts: 70
Joined: 20 Aug 2016 15:49

Re: 1650 carrier + tone

Post by KPC850 » 21 Apr 2017 08:33

heard it for the first time last night 1650kHz AM after reading your post.
The tone was not continuous, there was a pause of the tone every 10+ or so seconds.
There was significant fading up and down in signal strength over several minutes

It is here :

https://www.youtube.com/watch?v=dJJcwOHxKNE

and as being from Brest, but the ferrite rod null seemed to be a bit more west than Brest from me, perhaps north-west Spain (or 180 degrees the other direction from me) ?

I'll see if any sign of it in the middle of the day (groundwave) when I can, I'm near Cork Ireland

Brookman Spark
Posts: 90
Joined: 19 Jan 2016 18:15

Re: 1650 carrier + tone

Post by Brookman Spark » 22 Apr 2017 11:01

That's interesting, thanks KPC. It seems unlikely to be coming from Brest/Corsen. Its purpose may well be to protect the frequency against intrusions onto Corsen's maritime broadcasts but when Corsen is doing its SSB voice transmissions the tone+carrier is still present. It would be self-defeating to use the same site for both purposes.

I've noticed too that for a given time of day the carrier can be much weaker on some days -- not due to fading but seemingly using different transmitter powers. On a good day the signal is audible in daylight on SDRs in Yeovil, Salisbury, London, and Leiden. Surely Leiden would be too far from Brittany and indeed from Spain for daytime reception at that frequency.

Yes agreed there is skywave fading on it after dark.

I'm not hearing it at all right now on any SDR.

My money -- but not much money -- is still on a transmitter site somewhere further up (ie east) along the English Channel. Or La Manche if you prefer.

KPC850
Posts: 70
Joined: 20 Aug 2016 15:49

Re: 1650 carrier + tone

Post by KPC850 » 25 Apr 2017 14:16

No sign of it in daylight (when tried Saturday)

Yes it seemed to have got weaker and weaker with me since I posted above. Last night I gave one try and I couldn't hear it. Switching on BFO, I could tell there was a very weak carrier on 1650 but that could have been something else. (In comparison a data signal on 1680 was easily heard? - anyone know location of that?)

Where I was, the 1650kHz null was a bit further west than the DRM on 1071 (as a guide). So I would rule out the English Channel. It could perhaps have been around northwest Scotland (or somewhere else 180 degress the other way) However daytime reception - (if it was groundwave) - in London etc would rule that out ?

Could it have been transmitted (for whatever reason) from a ship at sea, which has got weaker and weaker as it traveled ?

Brookman Spark
Posts: 90
Joined: 19 Jan 2016 18:15

Re: 1650 carrier + tone

Post by Brookman Spark » 25 Apr 2017 19:03

Yes the reception characteristics of this one have altered over the last week or so, and ship-borne transmission does seem a possibility. So a changed (and still changing) location rather than reduced transmisssion power.

There is no longer any daytime reception on any of the SDRs which had it a couple of weeks ago. It's fading in from nothing on the Yeovil SDR now.

One useful thing is I've been able to log both of the unrelated CROSS evening transmissions on 1650 USB: 18:15 UTC from Corsen and 18:33 UTC from Cap Gris Nez, confirmed here: http://f1agw.free.fr/Smdsm/Smdsm.htm#Large

Thanks for checking it. I'll let go of this one now as the original thought -- a counter-measure against Dutch pirates from somewhere on the English Channel coasts -- doesn't appear to fit.

KPC850
Posts: 70
Joined: 20 Aug 2016 15:49

Re: 1650 carrier + tone

Post by KPC850 » 26 Apr 2017 10:14

Tried around 12:30 AM this morning, no sign of it or anything on 1650 at all. In the AM 'X-band' area I received music on 1625kHZ and 1636kHz AM (I presume from Netherlands) as well as data on 1680. This with a Grundig YB400 on its own (not using any external antenna)

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