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DSC 8414.5 transmission

John Pumford-Green
 

Gents,

The Dotting transmission on 8MHz is still going on, although quite weak here at present. It's been there now for several days, but fades away from time to time due to propagation changes. A radio somewhere is doing sterling service as a broadcast TX - I'd guess that a ship-born transceiver might have fallen over by now, so perhaps it's a "proper" radio at a coast station.

I doubt we'd have much joy trying to DF it, without a decent rotatable beam for 8MHz. A small loop like the Wellbrook 1530 won't have much directivity for skywave signals on HF. We need someone with a big log periodic on a tower to help!

Cheers,

John

On 19/02/2014 18:56, Dirk Claessens wrote:


Hi Dryden,

4 peaks are clearly showing on the spectrum. This can only occur for the
"dotting" signal normally preceding a transmission.
A system on test? We have had a similar incident 6 months back with a strong
carrier on 518 Navtex. By combining several bearings it was found to be a system
located in the Dutch naval transmitter site of Scheveningen.
But taking a bearing on 8MHz could be tricky...

Regards - Dirk




--------------------------------------------------------------------------------
*From:* "denno9@..." <denno9@...>
*To:* dsc-list@...
*Sent:* Wednesday, February 19, 2014 5:53 PM
*Subject:* Re: [dsc-list] DSC 8414.5 transmission [1 Attachment]

This QRM is still coming through here, the PA must be getting a bit warm by now?
73
Dryden




Dirk Claessens
 

John & all,

For what it's worth, this afternoon at 16:15 utc and on the whip, the signal was -105dBm here with IF BW 500Hz. At times strong enough to cause YaDD to go in "dotting sync" (yellow LED). Right now at 2000UTC, it's still present but very weak.

RX location: 51.07.23N 04.28.03E [JO21je]

Cheers - Dirk




From: John Pumford-Green
To: dsc-list@...
Sent: Thursday, February 20, 2014 8:27 PM
Subject: Re: [dsc-list] DSC 8414.5 transmission

 
Gents,

The Dotting transmission on 8MHz is still going on, although quite weak here at
present. It's been there now for several days, but fades away from time to time
due to propagation changes. A radio somewhere is doing sterling service as a
broadcast TX - I'd guess that a ship-born transceiver might have fallen over by
now, so perhaps it's a "proper" radio at a coast station.

I doubt we'd have much joy trying to DF it, without a decent rotatable beam for
8MHz. A small loop like the Wellbrook 1530 won't have much directivity for
skywave signals on HF. We need someone with a big log periodic on a tower to help!

Cheers,

John