[RFI] CATV Leakage? Horizonal Osc Harmonics

larryW8UJ bestkoz22 at yahoo.com
Mon May 11 06:38:30 PDT 2009


I've been dealing for years with strong RFI on 160 and 80 that appears every 15,734 KHz - It's hard to get an exact center measurement of each harmonic as the signal peak is broad. 

I decided to get into solving the problem, thus the post.

I've uncoupled and unplugged (from AC) all the TVs,VCRs, DVD equipment as well as any cellfone or cordless fone chargers. I also found the RFI in the AM broadcast band around 1510 on the dial - this using a battery powered AM portable. I can't track down the RFI source with the portable to any nearby pole.

[In the past I managed to null the RFI with a MFJ bridge circuit designed for the purpose (used a short sense antenna along with the lead from the dipole).]

We aren't on the CATV system and have no CATV drops to the home. Since interference does abate for periods (seems to happen on the half-hour time-wise, I have speculated that there's a bad termination on a CATV port somewhere and perhaps a neighbor's set is being turned off after their viewing is completed. 

Or, I've wondered if the CATV provider uses chargers in those DA's that one sees hanging on the poles here and there. Needless to say, so far no response from Comcast.

Enough already - any ideas or experiences? Thanks,
Larry Kozal W8UJ

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