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[TowerTalk] Matching 75 ohm hardline for 3 bands

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Subject: [TowerTalk] Matching 75 ohm hardline for 3 bands
From: (Pete Smith)
Date: Sat, 31 Mar 2001 12:49:07 -0500
At 10:28 AM 3/31/01 -0600, JayTerleski wrote:
>I sent a message directly to Micheal the originator of this thread but I
>see from many comments that one solution that always works was left out.
>I have tried to do the ingore the SWR approach of Steve LXC, and also
>this approach of multiples of 1/2 WL with CATV.  Neither has proved

Despite the theoretical difficulties, I have found the multiple 1/2
wavelengths solution to be highly practical in my situation, where the
length of the 75-ohm CATV hardline is about 220 feet.  My 2:1 SWR bandwidth
is wider than the ham bands from 20-10 meters, significantly exceeds my
antenna's spec on 40 meters, and is no different than the bandwidth
measured at the antenna on 80.  If you have an amp that requires 1.5:1 SWR
or better, there may be reason for another solution, but this one works for
me, and the price is sure right by comparison.

A hint -- calculate your half-wavelengths multiple at the lowest intended
frequency, but measure with an RF-1, MFJ-259B or equivalent at the highest
harmonic for greatest precision.  Using a pigtail of RG-11 is a lot more
convenient than trying to trim the hardline to precise length.

73, Pete N4ZR
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