[RFI] Two meter interference

Cortland Richmond ka5s at earthlink.net
Sun May 11 11:47:02 EDT 2003

There are a number of possibilities. One is video carrier leakage from
Cable TV channel E -- and if you don't get it on your own Cable it may be
an illegal hookup by another tenant. Another is a scanner's local
oscillator (some of the old ones are _strong_).  In the latter case, a
Regency scanner using a 10.8 MHz IF might use a 145.26 MHz LO for the
Minnesota Department of Transportation at 156.06, or a 10.7 MHz IF scanner
might be tuned to 155.97 (also a Minnesota DOT frequency). 

The buzzing, and its wideband nature,  makes it sound like Channel E video
carrier -- and if you report a suspected illegal hookup in your building,
the cable folks'll be down there like hornets out of a kicked nest. 

It could be a tenant's computer, game or HDTV video display.  Some are
quite noisy.  Also, a number of devices are now deployed to support
broadband and telephone service, many, in my opinion, improperly located in
or near residences. These are often in basements or attics, or bolted to
building walls.  A poorly laid out board is easily capable of interfering
(got that bloody shirt) all the way up through 2-meters with only a ~1 MHz

For cable TV channels see http://www.arrl.org/tis/info/catv-ch.html
and for local law and business  frequencies, check out city.com. 
(Saint Paul listings at http://www.cityfreq.com:81/mn/stpaul/ )


PS: If you know anyone needs an RFI/EMI engineer -- I'm looking for work.

> From: Jerry <k0hzi at attbi.com>
> To: <rfi at contesting.com>
 > Date: 5/11/2003 9:34:40 AM
> Subject: [RFI] Two meter interference
> There is a steady carrier on 145.260 to 145.265.  Have turned all AC 
> power off in my apartment and it is still present.  I used the 
> attenuator feature of my TH-F6A and have snooped around the apartment

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