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[RFI] Interesting Case of Interference

To: <rfi@contesting.com>
Subject: [RFI] Interesting Case of Interference
From: na9d-2 at speakeasy.net (Jon Ogden)
Date: Wed Jan 22 07:25:00 2003
There's a couple of questions about the CATV theory:

1.) You mentioned that you heard voices like a DJ.  I've had digital cable
and on the music channels they carry, there are no voices or commercials.

2.) I'd expect you'd hear programming other than music?  Is that the case?
And does it show up in just one place?

3.) If the CATV system is leaking, then you will get into it.  So fire up
the amplifier and start pumping some Watts in the direction of the cable
lines.  It's not your fault if you get in.  But if you are, I can almost
guarantee you they will be out quickly to fix the problem as they are
supposed to be a closed up system.

It's certainly an odd problem.....

73,

Jon
NA9D

on 1/22/03 12:38 AM, Cortland Richmond at ka5s@earthlink.net wrote:

> I can't say for sure, Tom; it's possible.  The cable signal is at RF to start
> with and they are probably using the HF spectrum; it's already used in some
> analog systems.  It could also be cable company or subscriber owned equipment
> that is decoding the digital signal (as in the CD player example), too. Got a
> portable receiver?  Seems to me if the signal goes 'waaay up near the wire or
> its connections, it's their signal, and if it only goes up near their box, its
> the box. But that's a VERY loose guess, troubleshooting, so to speak,  by
> telepathy.
> 
> An argument for signal is that it sounds like power line noise, which (I am
> speculating) is probably digital frames synchronized to NTSC sync so as not to
> interfere with analog Cable channels. An argument against it being the signal
> is that from time to time it goes away.
> 
> Recourse? Well, its similar in effect and delivery to power company static.
> One difference may be that right now the FCC -- actually some folks in
> Congress who tell the FCC what to do -- is pushing universal broadband access,
> and they may not want to deal with the cable firms as they deal with the power
> companies. 
> 
> This is another thing ARRL needs to be watching out for.
> 
> Cortland
> 
> ----- Original Message -----
> From: Tom Crothers <mailto:k8ana@insight.rr.com>
> I think you're onto something there.  Insight Communications just put in
> digital cable down my road.  I hear the interference when my beam is parallel
> to the cable run (for what that's worth).

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Citizen of the People's Democratic Republik of Illinois

Life Member: ARRL, NRA
Member:  AMSAT, DXCC

http://www.qsl.net/na9d   <- Updated on 1/12/03!!!

"A life lived in fear is a life half lived."


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