Some questions that need to be answered regarding the
"birdie" problem I'm having with a recently acquired UPS system.
The UPS system I'm using is an APC brand UPS. Others using APC
brand UPS systems have reported no birdies heard on HF.
I'm hearing the birdies on the VHF weak signal bands where
even the tiniest of birdies can be heard in a good receiving
system. I suppose these birdies may be present on HF but are
below the ambient band noise. Try listening on 10m at night and
see if they are heard. According to Zoli (see below) there is a
good reason why they are every 10KCs. If it is true that it will
be almost impossible to get rid of the birdies then the wife
will probably acquire a new UPS and I'll go without!
73 Ken N4UK
<---- Begin Forwarded Message ---->
From: z.pitman@libertel.nl
Subject: UPS
To: ramirezk@emi.com
Hi Ken,
Sorry to say, but I wouldn't bet on your success. The UPS has an
oscillator
(app. 10 KHz) and its signal is used like a switch controller.
The UPS
radiates itself and the signals getting out (mains, outlets)
make
intermodulation everywhere. The function between the price and
the EMC
quality is exponential.
If you want to have a professional (=long-term problem-free)
solution use
accus and get rid of those switching power supplies, UPSs etc.
In HA we had
lots of problems with PC and PS noise. A major step to clear
those birdies
up was to use 2 gel-accu's for 12V/105Ah to feed the PCs
(notebooks
requireing 12V DC). (Altough I suspect that transporting 105Ah
accus to Cabo
Rojo is not the challange you dream of)
Clearing your spectrum from the UPS noise could be worth for a
PH.D. on the
field of EMC.
73s de Zoli PA/HA1AG
Tel> +31 43 355 7012 (between 0930 and 1700 GMT)
Ps> I enjoyed your WPX-story. Keep up posting them!
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