[RFI] 144 MHz Interference Source

[Jim Brown]

Greetings to the list. I'm a new member, but an old timer (Extra since
1959) and vice-chair of the EMC Working Group of the Standards
Committee of the Audio Engineering Society.  I'm back on the air after
a long absence, and just bought some radios, including an FT-100D that
lets me get on 2m CW. I'm primarily a CW guy, working mostly the HF
bands. 

My first post is a question about an interference source that I'm
hearing at the low end of 2 meters and just below it. The carrier
frequency appears to be about 143.995 MHz, with periodically spaced
sidebands extending above the carrier for at least 100 kHz into the 2 m
band.  I can hear this source both with the FT100D and with my TH6
handheld, and it appears to be fairly local to my QTH. It dies out
pretty quickly when more than about 400 ft away. Principal sidebands
seem to be at roughly 3 kHz spacings, and all sound like carriers. 

I live in a wood frame 2-flat in a Chicago residential neighborhood
about a mile north of Wrigley Field. I've shut down everything around
my home that I can think of (computers, printers, radios, home
entertainment gear, etc.) and the noise is still there, but haven't
been through my tenant's apartment, and I haven't talked to neighbors
yet.  

My internet access is via cable, and my tenant also has cable. 

Any ideas what the source of this is?  One of the things I've sort of
suspected is cable TV leakage. 

Jim Brown
Audio Systems Group, Inc.
Chicago
http://www.audiosystemsgroup.com