[BC] Can't Get A Direct Answer

[Tom]

The two I referenced earlier are Smart-UPSs... no discernible 
interference on any frequency of interest here.  One thing I should 
mention - one of the UPSs is being fed through a surge suppressor, 
although the other one is plugged directly into the wall.  They DO 
recommend direct connection, rather than using extension cords, to 
power the UPS if possible.  Try ferrite chokes if you must use an 
extension cord.  (The one on the surge suppressor IS on an extension 
cord; I believe the suppressor may be helping kill the RFI - if 
indeed the unit is generating any.

Tom S.

Rik van Riel wrote:
>On Wed, 24 Oct 2007 10:47:06 -0400
>Tom Dimeo <mwam at 73kn.net> wrote:
>
>
>>I've purchased two UPSs, a Tripplite and an APC and both of them 
>>cause interference to the AM broadcast and shortwave bands.  I've 
>>written to APC, Belkin and Tripplite trying to find out if they 
>>have a UPS that does not cause this kind of interference
>
>I have an APC Back-UPS 1000 here at home, which does
>not seem to cause much trouble.
>
>According to a discussion on freenode #hamradio, the
>Back-UPS series are offline UPSes that mostly keep the
>battery out of the loop, while the APC Smart-UPS are
>online UPSes that cause RFI problems.
>
>OTOH, I am seeing some RFI on eg. 10780 kHz and have
>not tracked down the cause yet.  The interference is
>strongest right in front of my monitors (when searching
>with a portable radio), but completely unplugging the
>monitors has no influence on the strength of the
>interference on my R75 (which has an antenna in the
>attic).
>
>Unplugging the UPS has no influence on the interference
>either.  It may be coming from somewhere else in the
>house, conducted here.