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Re: [TowerTalk] Low Pass Filters: Are They Of Any Use Today ?

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Subject: Re: [TowerTalk] Low Pass Filters: Are They Of Any Use Today ?
From: "Bill Winkis" <>
Date: Tue, 17 Apr 2012 11:16:41 -0400
List-post: <">>
Be Careful ... 
During the conversion of analog to digital TV, there were millions of  A to
D TV Converter Box's sold to home owners .... the transition channel in
getting the output of the converter box into a analog TV was either channel
3 or 4 ...... local guys that pulled their Low Pass filters soon found they
had to put them back .... 
The biggest example was the ham that lived in a single building multi
apartment complex that offered tenants either a feed off the MATV antenna or
local you pay for it cable...The retired folks who could care less about
cable chose the antenna and a converter box that the government gave them
free.....Yep..wavy lines on channel 3....

-Bill ....KC4PE

-----Original Message-----
[] On Behalf Of Steve London
Sent: Tuesday, April 17, 2012 9:42 AM
Subject: Re: [TowerTalk] Low Pass Filters: Are They Of Any Use Today ?

On 4/16/2012 12:20 PM, Jim Brown, K9YC wrote:
 > Given that the vast majority of TV's are on Satellite or Cable, is their
 > anything to gain by sticking a Low Pass Filter in the Transmission Line ?

 > Put very simply, NO. And even if a TV is on an outdoor antenna, it's
 > hard to find a good reason for an LPF. Since the final shutdown of
 > analog TV several years ago, nearly all broadcasters have abandoned TV
 > channels 2-6, so 174 MHz is the lowest frequency still in use in 95% of
 > North America, and the majority of TV broadcasters are on UHF.

As a first-order approximation, Jim is correct.

However, the low-band VHF channels have not been totally abandoned. There
even new applications for use of these channels. W9WI's web site has a
wealth of 
information on USA and Canadian TV channel allocations (

Steve, N2IC

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