Towertalk
[Top] [All Lists]

Re: [TowerTalk] Introduction

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Introduction
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 3 Feb 2017 10:02:50 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi Paul,

Sounds like a wonderful QTH. Good that you've learned about HFTA. Also read my applications notes about antennas, especially those talking about horizontal vs vertical and height of both, and the one about 160M. The modeling that produced these notes was based on "flatland," and HFTA modeling should dominate your thinking when it's not flatland. But the lower you go in frequency, the greater the benefit of greater height. k9yc.com/publish.htm

1 dB max is a good rule of thumb about feedline loss. My 120 ft tower is 250 ft from my shack. The antennas on it are fed with 7/8-in hard line, all of it used, that I've scrounged from various sources. To get HFTA, you'll need to buy the ARRL Antenna Book. That's good -- it's an excellent reference, and the CD also includes N6BV's TLW program, which lets you calculate loss for most available feedline types for any length and any frequency.

By the time you do everything necessary to build it safely -- foundation, rated hardware, the tower itself -- low loss feedline is a fairly small part of the total cost. Also -- feedline loss increases with frequency. My 160M antennas are also about 230 ft from the shack, but I'm feeding them with a low loss RG8, and the loss is still only about 0.5 dB.

73, Jim K9YC

On Fri,2/3/2017 9:11 AM, Paul Beckmann wrote:
Question set 1: Considering coax losses/expense how do you balance them
against tower distance from the shack? What distance is "typical" and what
distance is generally considered "unreasonable" from shack to tower?


_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>