[TriLUG] Television & RF interference -- yes computer related -- I think

Glenn Starling multifacetedguy at gmail.com
Wed Mar 6 21:17:06 EST 2013


James,

Several things could cause it.  Here are some possibilities in no
particular order.

* There is a ground loop in the AC wiring that causes this interference
only when an air conditioner or other intermittent device kicks in.
* A cron job or equivalent software that kicks in and effects the
computer's ability to process the video.
* RF signals from a transmitter.  Usually transmissions last only a few
seconds to a minute or so for CB and ham operators and varies in length per
transmission.  AM interference from CB usually is constant while the
microphone is pressed.  SSB signals from ham transmitters cause
interference that varies by syllable as the person speaks and is usually
easy to recognize as speech.  Ham FM transmitters cause constant
interference for the entire transmission.
* Interference from wireless mics, wireless headsets, and remote control
gadgets sometimes used in church media productions.
* Really weird stuff like a bad microwave heating bottles for nursery kids
or heating snacks for preschoolers or children in "children's worship".

If it is RF interference, checking for bad solder joints in video cables or
bad shielding on a particular cable might locate the problem.  A ferrite
core placed around the video and audio cables near the connectors might
solve the problem.

GOOD LUCK!

-- Glenn Starling
WB4UGH

On Wed, Mar 6, 2013 at 8:10 PM, James Jones <jc.jones at tuftux.com> wrote:

> All,
>
> Since there are some ham operators on this group, I thought that I
> would present my dilemma here.
>
> A Friend asked for me to help trouble shoot their church video
> problems. They video recorded their sermon on a Mac from a video
> switcher through several pieces of equipment to their mac. All their
> monitors had clear pictures of the video, but the Mac had a beat
> pattern in the video.
>
> The beat pattern would show for a couple of minutes, then clear up for
> a few and then back again. I am thinking it might be walkie talkies,
> handhelds or some nearby rf communication center of some sort. Since
> it happens only on Sunday morning and not during their Wednesday
> evening service, I believe it might be a ham operator, cb'er, etc.
>
> Need any and every thought on troubleshooting this problem.
>
> Thanks in advance
>
> --
> Jc Jones
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