[HFbeacons] Re: UPS interference
- From: "Lyn Williams" <wa4geh@xxxxxxxxxxx>
- To: <hfbeacons@xxxxxxxxxxxxx>
- Date: Mon, 23 Dec 2013 16:53:24 -0500
A company I used to work for manufactured HF transceivers with switching power
supplies.
On the input to the power supply there was an Powdered Iron Core Toroid with
two windings....same number of turns on both of them. Each winding had about
10 turns. The AC power in went through the toroid...wired such that the two
windings were 180 degrees out of phase. The idea was noise from either side
would be induced in the opposide side of the power line exactly 180 degrees in
phase and at the same amplitude...causing a perfect cancellation of the noise.
It worked pretty well at 40 kHz which was the power supply switching frequency.
73,
Lyn
WA4GEH
----- Original Message -----
From: cactuscharlie
To: hfbeacons@xxxxxxxxxxxxx
Sent: Monday, December 23, 2013 4:37 PM
Subject: [HFbeacons] Re: UPS interference
One possible help would be liberal use of clip-on ferrites. On the AC & DC
sides. I found that 3 or 4 close to the APC Unit. It has worked for me.
If the ferrites are large enough, put 2 turns thru..
73,
Chuck, AC7GZ
-------- Original message --------
From Bill Riches <bill.riches@xxxxxxxxxxx>
Date: 12/23/2013 11:30 AM (GMT-07:00)
To
hfbeacons@xxxxxxxxxxxxx,navtexdx@xxxxxxxxxxxxxxx,ndblist@xxxxxxxxxxxxxxx,perseus_SDR@xxxxxxxxxxxxxxx
Subject [HFbeacons] UPS interference
Have been tracking down intermittent RF interference while using my Perseus
for beacons and navtex. There would be a raspy signal starting about 130 KHZ
and harmonics 260 KHZ and the baddie at 520 KHZ. Its signal strength is about
s9 on the receiver. It sounds like a buzz saw and is on every 10 seconds or so
for about 3 seconds. I thought that it was from power company stuff - meter
reading, switching signals, or even our neighbor's dog fence! Not so. It is
in my home. Fired up a portable am radio, set it on 520 KHZ and the racket was
loud and clear in the shack. Turned off the power mains and it went away.
Found that it was coming from my APC XS1500 computer UPS! Seems the swichmode
battery charger in the unit is working fine! Every 10 seconds.
I called APC and tried to talk with a tech and that did not happen. The
"tech support" person suggested a power strip! I asked if they had any units
in their line that did not have this interference and she said she would check.
After 5 min she said no we dont.
Have any of you found a UPS that may not have this problem?
73,
Bill, WA2DVU
Cape May, NJ
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