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Legend
Junior Member
Username: Legend

Post Number: 18
Registered: 12-2002
Posted on Sunday, March 14, 2004 - 2:35 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hiya...

I have a quick question for the Techs. I have read in a couple of places that the TVI filter should be placed AFTER the amp. ie... between the amp and the antenna.

However, I was wondering... since an amplifier amplifies the undesireable harmonics, as well as the fundamental desired base frequency, wouldn't it be possible to do a better job at knocking down harmonics by not amplifying them to begin with? ie... to place the TVI filter BEFORE the amplifier.

I read one Techs comments where he said that he attaches his TVI filter directly to the back of his radio via a double ended connector, but I don't know whether this gentleman uses an amp or not.

At any rate, I am not a tech, and I very well might not understand which way is correct. That is why I am asking for the semi-technical explanation as to which way is correct.

Thanks, guys.


One of the reasons that I love this forum, is because I can slowly but surely, get answers to every question I have ever had concerning CB/Ham radio. Until, eventually, I will have the ultimate set up!

:-)
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Tech808
Moderator
Username: Tech808

Post Number: 1805
Registered: 8-2002
Posted on Sunday, March 14, 2004 - 3:06 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Legend,

You are probably refering to one of my post's on TVI Filter's.

The answer is Yes, if I am running just a Straight Radio the TVI Filter is grounded along with the Radio and run directly via a Double Male Connector from the back of the radio to the TVI FILTER and the Coax attached to the other end of the TVI filter going to the Antenna.

If I am useing an Amplifier I ground the Radio, and the Amplifier and the TVI Filter and connect the TVI Filter Directly to the Amplifier via a Double Male connector and then connect the Coax to the Antenna to the other end of the TVI Filter.

Hope this help's.

Lon
Tech808
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Bigbob
Senior Member
Username: Bigbob

Post Number: 1750
Registered: 12-2001
Posted on Sunday, March 14, 2004 - 9:21 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Lets get this straight so there is no confusion,a tvi filter is little and most of the time is meant to go inline on cable tv or tv coax,what gos in line right after the last unit in your radio system is a low-pass filter it filters out anything above 30 megs,so your radio dosent cause problems with the neighbors tv,a low-pass filter is commonly called an rfi filter have never seen one called a tvi filter,but my scope is rather narrow.Bigbob
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Tech808
Moderator
Username: Tech808

Post Number: 1808
Registered: 8-2002
Posted on Sunday, March 14, 2004 - 10:35 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Bigbob,

My MTI ~ TVI Filter's that I use has:

LOW-PASS
TVI

Television
Interference
Filter

LM-TVX2

for
Radio
Transmitter
Antennas
1.8 - 30 MHz


On the label on the Filter.

I have used the MTI TVI Filter's for over 25+ years now.

Lon
Tech808
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Bigbob
Senior Member
Username: Bigbob

Post Number: 1762
Registered: 12-2001
Posted on Monday, March 15, 2004 - 7:52 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Well they named it WRONG,SO THERE,NYA,NYA.LOLOL.

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