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Author Topic: TVI in reverse  (Read 317 times)
KB6YH
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Posts: 43




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« on: June 14, 2008, 10:17:32 PM »

The horizontal oscillator of my  55 inch Mitsubushi TV is very strong on 80m and 40m. It enters my IC745 via the antenna not the AC line. Is there any way to filter out TV signal using a filter on the radio's coax? Thanks!
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AC5UP
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Posts: 3834




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« Reply #1 on: June 15, 2008, 03:02:41 AM »

TV Birdies have been a fact of life since the days when Ralph Kramden threatened to send Alice to the moon.

Your best bet is to try shielding the TV. The QRM is so broadband that filtering at the HF receiver is a non-starter. In the case of a big screen model the horizontal oscillator can have some moxie but it might be possible to glue some aluminum foil inside the TV cabinet to attenuate the pattern, especially in proximity to the flyback transformer. If that doesn't sound like a good idea consider a large-ish Velvet Elvis with a foil backing hung on the wall between the TV and your antenna farm.

Might also try changing the orientation of the set... A walk around with an AM radio might tell you where the hottest lobes are.

(?)
 
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KB9CRY
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Posts: 4284


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« Reply #2 on: June 15, 2008, 04:54:14 AM »

No, you need to deal with the RFI at the source, i.e. the TV.  Turn it off when you operate.
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TANAKASAN
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Posts: 933




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« Reply #3 on: June 15, 2008, 05:22:50 AM »

OK, put this down to a culture clash but I've got to ask.

What's a velvet Elvis?

Tanakasan
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W5GNB
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Posts: 419




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« Reply #4 on: June 15, 2008, 05:52:16 AM »

If possible, you could relocate your ham antenna to a point more distant from the tv.  You may also be able to orient the antenna to where you can somewhat null out the interferrence.
I don't know of any filter that is effective on this type of interferrence since the emmissions are so broad.  I know my noise blanker has no effect on this type of noise.....

Good Luck!
Gary - W5GNB
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W3LK
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Posts: 5644




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« Reply #5 on: June 15, 2008, 06:14:11 AM »

<< What's a velvet Elvis? >>

Child! Smiley

It's a painting of Elvis Presley on black velvet.

73,

Lon - W3LK
Naugatuck, Connecticut
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AC5UP
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Posts: 3834




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« Reply #6 on: June 15, 2008, 09:25:42 AM »

When no-one else can understand me
When everything I do is wrong
You give me love and consolation
You give me strength to carry on

And you're always there to lend a hand
In everything I do
That's the wonder
The wonder of you
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KB9CRY
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« Reply #7 on: June 15, 2008, 01:59:14 PM »

He's the King!

If you don't know what a Velvet Elvis is, then don't ask because we can't tell you in today's tattle-tail culture.
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K1BXI
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Posts: 812




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« Reply #8 on: June 16, 2008, 06:44:34 PM »

Stopping it at the source is the best way, however a phasing type noise canceling device will work well on that type of "reverse TVI"

I have an MFJ-1025 that will phase out a TV birdie very nicely. Also works on computer type RFI.

John.....K1BXI
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