Message-ID: <001201c44eca$35af7cb0$6a00a8c0@athlon>
From: "Dave Brown" <tractorb@ihug.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <5.2.0.9.2.20040519074411.01fa5ab8@pop.vianw.pt> <000501c44dfb$bdf38640$7a1686d4@erica> <000b01c44e12$4a02eca0$6507a8c0@Main> <001b01c44ec9$0bd64000$edc828c3@erica>
Date: Thu, 10 Jun 2004 21:06:25 +1200
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Subject: LF: Re: Re: Re: Re: Off Topic---QRM
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Basic rate ISDN lines usually have a locally powered (ac mains wall wart
etc) NT at the customer premises-if the power goes off this will stop
'talking' to the exchange end-which it is normally doing on a continual
basis-even if no calls are established.
Pair gain systems (0+2, etc), on the other hand- usually are powered from
the exchange end, and would keep running despite local power being off.
 The former would be unusual in a suburban environment- the latter may be
quite common.

Whether or not this info is relevant is another matter!
73
Dave, ZL3FJ

----- Original Message ----- 
From: "g3ldo" <g3ldo@ukonline.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, June 10, 2004 8:57 PM
Subject: LF: Re: Re: Re: Off Topic---QRM


>
> Alan Melia said
>
>
> > Hi Peter, the immediate thought is DSL ( or ADSL) or even ISDN lines. I
> > would not lay too much store by BT "engineers" not being able to find
it.
> > These guys have little or no RF experience in general. Because it is so
> > wirespread, I would suggest it is a system effect rather than a fault
> > somewhere, and it would seem to correlate with the increased penetration
> of
> > "broadband". This could explain why some "diss poles" are not as noisy
as
> > others.
>
> Many thanks to Alan and the rest of you who responded regarding my QRM
> problem.
>
> I don't think that the noise is generated by BT even though it is being
> radiated by some of their distribution systems.
> Last week we had a power cut that affected an area of around one or more
km
> radius and the noise (almost) disappeared. I think most ISDN etc is
powered
> from the exchange.
> All the interference comes down the antenna. I can reduce it considerably
by
> parking my beam so that the deepest null is on the source of the noise.
The
> noise is very broadband (I can hear traces of it on the 10 and 18MHz band)
> and is average S7 throughout the 14MHz so not an apparent harmonic.
>
> Peter, G3LDO
>
>
>