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Re: [TowerTalk] Antenna Distance From Shack

To: Robert Chudek - KØRC <>,<>
Subject: Re: [TowerTalk] Antenna Distance From Shack
From: Pete Smith <>
Date: Fri, 18 Aug 2006 15:06:49 -0400
List-post: <>
You're right, Bob, it was a typo.

The idea was that I wanted to have a half-wavelength (or close to it) at the 
lowest frequency of operation, meaning 160 meters.  But I also wanted to 
measure as accurately as possible, which meant measuring at 28 MHz.  I used an 
RG-11 pigtail so that I could get the length within an inch or so of being x 
half-waves at 28 MHz.

As for the loss measurements, W8JI told me that with a composite feedline like 
this, I could not get a usable loss number.  The 259B manual says "be sure the 
distant end... is not terminated in any resistance" and also says that 
non-50-ohm systems cannot be measured.

73, Pete N4ZR

At 01:23 PM 8/18/2006, Robert Chudek - KØRC wrote:
>Hi Pete,
>Can you elaborate on the "1750 Hz (measured at 28 MHz) of 3/4" CATV" you 
>mentioned? First, I assume you meant 1750 KHz, but aside from that, I'm not 
>following what you mean.
>Also, measuring loss at the shack with the MFJ-259B... Unless you install a 
>non-resonant 50 ohm terminator at the opposite end, your readings in the shack 
>will continue to 'vary widely' (although maybe not as "widely"). If you 
>installed a 50 ohm load on one port of a remote antenna switch that would 
>accomplish the task, but I'm thinking this is not what you had in mind 
>regarding measuring loss.
>73 de Bob - KØRC in MN
>Message: 2
>Date: Fri, 18 Aug 2006 08:13:14 -0400
>From: Pete Smith <>
>Subject: Re: [TowerTalk] Antenna Distance From Shack
>Message-ID: <>
>Content-Type: text/plain; charset="us-ascii"
>Frank and Bill make good points.  For the last 10 years, I have been using 
>3/4" CATV for most of the 190-foot run from my house to my antennas.  To be 
>specific, I use RG-213 up the tower and across the roof of my house to my 
>2nd-floor shack, but use multiples of a half-wave at 1750 Hz (measured at 28 
>MHz) of 3/4" CATV in between. 
>-- some stuff snipped here --
>I want to be able to monitor loss from the shack, something that my composite 
>feedline doesn't seem to let me do (the indicated loss on my MFJ-259B varies 
>widely with frequency).
>-- trailing text snipped  here --
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