Hi gang,
Has anybody compiled a list of active IARU HQ stations and their respective
abbreviations? Sure could use one.
73, Dave, WJ2O (FM/WJ2O this weekend)
>From n0dh@comtch.iea.com (Dave Henderson) Mon Jul 8 20:18:59 1996
From: n0dh@comtch.iea.com (Dave Henderson) (Dave Henderson)
Subject: 160M antennas and parts
References: <v01540b00ae056a1930fc@[206.119.237.36]>
Message-ID: <31E15F23.6312@comtch.iea.com>
Alfred J. Frugoli, KE6BER/1 wrote:
>
> I am in the planning process for a 160M contest antenna. I know that there
> is much to be said for inverted L's and towers as 160 antennas. I am
> currently looking at putting up either an inverted L or a 50ft top loaded
> vertical. Here are my questions.
Al I have used Inverted L's for years in the following configuration.
Total length on the "L" (verticaL + horizontal) of about 160' This raises the
feedpoint impeadance to around 50 ohms.
>
> 1) Are there any references out there on specific construction techniques
> for coils and matching networks. (I need these components to handle
> legal-limit)
In the above configuration I then use a series cap to tune out the inductive
reactance. The important thing in this configuration is the ability of the
cap to handle large amounts of current. typically you will be looking at
something around 300pf. I used to use three of the old 100pf 2.5kv surplus
transmitting type micas in parallel. I since got a very good deal on a 500pf
/ 5kv vacummn variable at a hamfest which allows me to do all my "pruning"
from the ground!
>
> 2) What are the effects of having the vertical portion of an inverted L
> next to a metal support (i.e. a tower).
I have never tried this as I always hang my L's form the trees but the
computer models suggest a reduction of about 1 to 2 db depending on the the
tower configuration.
> 3) Is there any antenna modeling software that will help me with figuring
> radiation resistance, capacative loading, matching etc that will run on a
> 386 w/dos, or a Mac?
I personally use NEC WIRES by Brian Beasley. It runs on a 386 ok. But to get
really good results a model with enough "segementation" could run for 10
minutes or more on 386/33. This is true of most any of the software packages
out there most of which are based on NEC or Mini_NEC. A math coprocessor is a
must.
OH yeah...plan on putting your money in the ground radials. I have two L's in
phase here. To date I have about fifty 1/4 radials under each one which
amounts to 13,000 feet of wire and I'm still adding on ! It will work with
less but if you wanna kick "@$$"..........
Dave
N0DH
dit dit
PS: There is a 160 meter "reflector" at <topband@animas.frontier.net>. To
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