[RFI] BOUNCE rfi@contesting.com: taboo header:

tduffy tduffy <tduffy@sygnet.com>
Sun, 11 Jan 1998 12:30:10 -0500

owner-rfi@contesting.com wrote:

> >From k3lr  Fri Jan  9 20:05:52 1998
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> From: ROBERT WANDERER <aa0cy@robertwanderer.gardnerville.nv.us>
> To: "'Markhasin, Vitaly        (SLI)'" <markhasin.vitaly@syncrude.com>
> Cc: "'RFI REFLECTOR'" <rfi@contesting.com>
> Subject: RE: [RFI] CATVI Reply
> Date: Fri, 9 Jan 1998 17:03:50 -0800
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> What I was actually referring to, Vitaly, was interference between
> cable TV and ham radio which usually occurs in the 144, 220 and
> 440 MHz regions between ham repeater inputs/outputs and cable
> TV video carriers being on or near the same frequency. Also problems
> can now occur on the bands between 40 and 10 metres because many
> systems are using 5-40 MHz as a return for two-way interactive (e.g.
> SEGA channel)
> Nevertheless, I'll be glad to assist, but I require further
> information. What
> bands? All the time or when your beam is facing them? etc.
> Some of things which you can try are: brute force ac line filters on
> both
> their equipment and your rig; a good low-pass filter on your exciter
> the linear; your equipment well-grounded RF-wise; high-pass filters on
> the
> televisions; try a known bullet-proof telephone on the affected lines
> to see
> if it's the phone or the line (advertisers in QST/CQ); likewise RFI
> filters on
> the telephones (ferrite beads work great but sometimes actually make
> the
> problem worse - what works on one phone not only doesn't work on
> another
> phone but exacerbates the problem); for stereos, make sure the speaker
> wires
> are not a resonant length; bypass caps (although some stereos will be
> damaged,
> check with the manufacturer) on the speaker leads by the output ports;
> maybe
> aligning the speaker leads so that they are not horizontal (zig-zag)
> or directly
> parallel to your antenna.
> Some early model cordless phones worked on a frequency very near the
> 160-metre
> band! And the other frequency used then was just below 50MHz. Now,
> they're mostly
> in the 800-900 MHz range. Since these are line powered, an ac brute
> force filter may
> help. I had a telco problem which wound up being the wall wart
> (actually the cable
> between the wall wart [transformer] and the telephone, which used the
> ac to light up
> the dial) and actually turned out to be a defective transformer on the
> pole!
> If the TVI is fundamental overload (occurs on ALL channels when the
> outside
> ANTENNA is plugged in), there is little you can do because the
> necessary cure
> is internal to the television set. Usually if there's cable involved
> and TVI, the culprit
> is a poor physical connection between the two (male-female) F
> connectors or between
> the male connector and the cable. This can occur anywhere there is a F
> fitting, which
> includes the tap on the pole (aerial) or pedestal (underground). Of
> course poor connections
> can occur on the [aerial] hardline anywhere in the vicinity! You can
> use a 2-metre FM HT
> on 145.25MHz to look for cable leaks (break squelch and synch buzz)
> and report them to
> the cable company; however, I don't know what relationship Canada
> enjoys relative to
> cable leaks. If you have a radio capable of picking up the air nav
> band, check those freqs.
> In the US, leakage on those freqs will trigger a panic attack. Just as
> with ac line noise
> problems, RF leakage from the cable plant can get onto the messenger
> and guy wires,
> but the latter is fairly rare.
> Good luck!
> 73, Bob AA0CY
> ----------
> From:  Markhasin, Vitaly
> (SLI)[SMTP:markhasin.vitaly@syncrude.com]
> Sent:  Friday, January 09, 1998 4:28 AM
> Subject:  RE: [RFI] CATVI Reply
> Hi Bob,
> On Thursday, January 08, 1998 10:48AM you wrote:
> >While I've battled my share of problems to and from televisions,
> >telephones, stereos, etc. amd will assist in those types when I can,
> >if anyone is having problem with cable television interference
> (CATVI),
> >I spent quite a bit of my 19 years in cable TV handling that issue.
> <snip>
> I have ALL of the above problems with my next door neighbor when
> running
> 1KW.
> I have ICE filters installed at my station.
> What can you recommend to do with my neighbor (cable TV, stereo,
> cordless phone)?
> Thank you.
> Vitaly (VE6JO)

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