Hi John 13.55MHz rings a bell for the ISM frequency, which is the US "HiFer"
allocation as well. Most of the kit I have seen (not a lot) in the last 20
years had crystal control, but the supply is not always that well smoothed.
Alan
----- Original Message -----
From: "John Rabson" <[email protected]>
To: <[email protected]>
Sent: 09 June 2004 12:03
Subject: LF: Re: Re: Off Topic---QRM
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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