[Hallicrafters] computer noise

[Peter May]

These bulbs can vary alot in the amount of has they generate, I bought some
that were very noisy and had to scrap them. The price of the bulb is no
indication on quality either.
Recently I've got some TVI problems which have proved impossible to track
down.
It's not really evident on the radio, but something has started up that is
killing my set-top box digital TV receiver.
On analog TV it's only evident as diagonal bars, shich seem to pulse a bit.
I suspect it's coming from next door as I've gone through my place
systematically shutting everything down. Someone mentioned wireless
broadband modems which has also crossed my mind.
I've put ferrites on all my cables, I'm yet to understand the value of
these, they appear to do nothing whatsoever. Who is conning who?


Regards
Peter


----- Original Message -----
From: "Joe and Ann Vlk" <jvlk at charter.net>
To: <hallicrafters at mailman.qth.net>
Sent: Saturday, December 24, 2005 11:43 PM
Subject: [Hallicrafters] computer noise


> Lots of comments on fluorescent replacement bulb generated hash.  I
recently purchased several 4 packs and 6 packs from Home Depot, installed
them thoughout the house (including the radio shack) and have not
experienced any hash from them.
>
> There were also side comments on computer/monitor generated noise.  When I
purchased my latest 64 bit processor super computer, it put signals all over
the bands.  I made a simple "sniffer" coil pick up and plugged it into my
756pro antenna socket and went sniffing.  I determined what every was
generating the noise in the computer (most likely the switching power
supply) it was being conducted through the computers power cord.  Various
clamp on power cord ferrites didn't seem to suppression the noise at all.  I
found a build project in my 1980 ARRL Handbook (that's right, 1980) for a
brute force filter.  I built one in a Radio Shack plastic project box and
wired it in series with the computers power cord.  All the computer
generated noise is now completely gone.  Glad I didn't trash that old
handbook, maybe I should buy a new one?
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