If I recall correctly, there is an ISM allocation slightly below 14 MHz
which is used for RF heating. Some of the power oscillators I encountered
did not have a very stable centre frequency and had a rather broad signal. A
colleague from South Africa told me that he always knew when the UK was at
lunch because the background noise on 20 m down there was much reduced.
73
John G3PAI
----- Original Message -----
From: "g3ldo" <[email protected]>
To: <[email protected]>
Sent: Wednesday, June 09, 2004 9:27 AM
Subject: LF: Re: Off Topic---QRM
For many months now I have been experiencing a peculiar electrical
interference. It is a rasping sound rather like a spark transmitter and
sending something like NX in very bad morse at around 5WPM. The QRM is
broadband centred around 14MHz and is on 24hrs a day.
I have reported the matter to BT who hav been out to investigate but are
unable to find the source or even say what it is.
I have also sent a tape to David Lauder, the RSGB EMC guru but even he
does
not know what it is.
With my bicycle mobile I have travelled around the vicinity in a radius of
around 3km of my QTH and find the QRM widespread with hot spots often by
telephone line distribution poles. Most telephone poles do not carry the
interference.
The interference does not affect 136kHz - hence Off Topic.
Regards,
Peter, G3LDO
e-mail <[email protected]>
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