[RFI] Cable TV Interference

[Cortland Richmond]

The FCC limit is not a requirement; it is a maximum. In the event of harmful interference, the cable company is _supposed_ to work to reduce it.  

You can build, buy or borrow a tuned dipole. Use about 11 or 12 dB for the antenna factor.  

(Check out 

http://www.ahsystems.com/catalog/data/AF_TDS-535_10meter.html 
http://www.ahsystems.com/catalog/data/AF_TDS-535_3meter.html 
http://www.itrc.ac.ir/ist-2001/sessions/Sat9.2.pdf
)

Once you have a resonant dipole, with an appropriate antenna factor, add that factor to your reading in microvolts to determine the microvolts-per-meter field strength. You can then compare this with what the FCC allows.  While reading a couple of dB over is not going to be supportable, given the lack of precision implicit in our measurement method (S meter and approximate antenna factor), a gross leak may be 10, 20 or even 30 dB over the limits, and it shouldn't be all that difficult to get someone's attention if you have taken SOME care with the measurements.

Good luck,

Cortland

-----Original Message-----
From: "Peter D. Vouvounas" <wb3fsr@home.com>
Date: Thu, 6 Dec 2001 09:20:21 -0500
To:  <rfi@contesting.com>
Subject: [RFI] Cable TV Interference


> Morning ALL,
> 
> Can anyone share their thoughts on how best to determine if cable TV
> radiation is within spec...
> 
> I am receiving a carrier on 145.250 MHz generally around S7-S9 signal
> strength = approx. 16-17 microvolts at the antenna port.  Using a VHF
> collinear on my tower.
> 

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