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Author Topic: VCR TVI  (Read 2890 times)
KC0IOX
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Posts: 28




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« on: January 15, 2003, 09:17:12 PM »

Hi there.  First, this is a great idea for a forum.  I'm glad the folks at eham.net put it together.
Lately, I've experienced TVI into my VCR, on 75/80 mtrs.  It takes out the video, but doesn't affect the audio at all.  I've tried a high pass filter on the VCR, to no avail.  I've also checked and re-checked the ground connections and tried a low pass filter as well.  Is there any other things I should try?  The TV is not affected, nor is the satelite dish, or the DVD player; just the video on the VCR, and only in the 75/80 meter band.  Any suggestions?  Thanks and 73
Eric
KC0IOX
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WB2WIK
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Posts: 20635




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« Reply #1 on: January 16, 2003, 11:25:14 AM »

This can be tricky, but I've had similar problems and always solved them.

High pass/low pass filters normally shouldn't do a thing to help this, and station grounding shouldn't either.

First thing I'd try is to make sure you're using the A/V outputs/inputs on the VCR and TV set, and not using the coaxial cable RF connection.  Then, I'd run the video cable several turns through a ferrite core installed over that cable.  See if that helps.  You might also try a snap-on ferrite RF choke on the AC power cord for the VCR, wrapping the cord through it 4-5 times before clamping it shut, and installing the choke over the line cord close to the VCR box itself.  See if that helps.

If not, it's possible you're getting into the video heads on the VCR directly, which means no amount of filtering outside the box is likely to help.  I've had this problem.  In the case of one particularly finnicky JVC (brand) VCR, I had to perform surgery on the VCR by taking it apart, unsoldering the tiny wires from the video heads, wrapping each one four turns through a small ferrite bead, and re-soldering the wires.  This takes a lot of light, a magnifying glass (at least for me!) and patience, not to mention a very small, low-heat soldering pencil.

But, it worked and solved the problem completely.

Of course, it might be easier to relocate the VCR or the antenna!  Sometimes re-orienting these two will dramatically reduce RFI.  In one stubborn RFI case I had in my own home, I had to move one end of my 80m antenna about ten feet to finally eliminate the problem.

WB2WIK/6
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