Hector (et al),
I've successfully reduced the size of my 160M inverted vee to just 100
feet, using loading coils. Performance appears to be quite adequate,
although I've taken no measurements other than SWR, due to lack of
instruments or software. I used 18 gauge magnet wire wrapped around a
PVC form. The legs of the antenna are just 50 feet long per side, for a
total length of 100 feet. I won't claim that its performance is
optimal, after all, it is a reduced size antenna, but I was able to tune
it to a 1.3:1 SWR without the use of a tuner. I've run the ARRL 160M
Contest with it in the QRP category and had little difficulty being
heard by any station I worked (I came in second in my division that
year).
I got assistance in designing the coils from this website:
http://ecosse.org/jack/radio/software/loading.html
This page will tell you what the loading coil inductance needs to be,
based on frequency, length of the antenna, the position of the coil, and
the diameter or gauge of the wire used to wind the coil. After you've
determined the inductance, go to this page to design the coil itself:
http://ecosse.org/jack/radio/software/newcoil3.html
73 de N8AU, Jim in Raymore, MO
Date: Fri, 11 Nov 2005 08:02:09 PST
From: "J. Hector Garcia XE2K" <hector@telecom1.net>
Subject: [TowerTalk] 160M DIPOLE USIGN COAX
To: towertalk@contesting.com
Message-ID: <BasiliX-1.0.3b-11317249294374c081435e3@web1.telecom1.net>
TT's:
I read the last NCJ, where K3LR 160m Dipole as sloper appears, i will
like to try something like this here, but i have only 140 ft of tower,
is possible to reduce the full size of the 160m dipole to a 66-70%
using only the RG-58 COAX as antenna not like feed, in other words use
the Vel Factor from the cable that is around the 66-70 to reduce the
physical length and make possible that configuration ?
the antenna is like this I> where I tower > dipole
i try to find something about this but nothing show up , jus the moxon
antenna using coax to reduce size, looks that work, really work ? and
i can use legal power ?
i will like to hear if someone before try and the result, before buy
the coax spool and just loose my time.
Hector XE2K/XF1K
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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