A lot, probably most, of the really cheap UPSes are just switching step-up
converters. The easy way to spot them is from the crazy ratings like "1000va"
but only 3 amps (which should be about 360va). They sell them based on people
thinking "bigger is better" even though a .36 power factor is pretty useless. I
used to always think apc's .7 was misleading... The big commercial units are
.8-.9.
I've personally always had good luck with the apc smartUPS line for small
upses. They are sinewave output (and surprisingly good when checked w/ a
scope), and pretty clean due primarily to their pseudo-ferroresonant design.
I'd stay away from the backUPS line though since those aren't much different
from the el-cheapo units.
Note that supposedly "bad" smartUPS upses can be found for cheap at swaps and
on ebay. Almost always all that is needed is a new set of batteries to get them
running again.
-Bill
[Sent using Blackberry Messaging]
----- Original Message -----
From: topband-bounces@contesting.com <topband-bounces@contesting.com>
To: TOPBAND <TOPBAND@CONTESTING.COM>
Sent: Wed Jul 04 18:14:07 2012
Subject: Topband: Progress with ugly computer noise
Be careful with UPS units as I have seen them cause more problems noise wise
that computers. A friend of mine had a really bad one he had to unplug to
operate on any band. Everything was clean once he got rid of that thing.. 73
Mike K4PI
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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