[Milsurplus] Need TCS antenna advice

Fri May 25 16:34:17 EDT 2007

Jim:

      For a couple of Boy Scout demos I constructed an NVIS-type of antenna system.  Check out http://www.vcars.org/tech//NVIS.html  for a design that mimics the military's AS-2259 SpecOps NVIS field antenna.  This one will need a tuner on any Amateur band you choose.

     Another approach would be to design a similar crossed-dipole NVIS antenna system that is cut for 80, 40 and/or 20M.  This is the approach I took for the Scouts; it can operate on any of the bands with no external tuner required.  Here's the design I based mine on,  http://www.w0ipl.net/ECom/NVIS/nvis_antenna_tri-band_web_ver.ppt#61  (careful: abt 7 MB file size) except I used telescoping fiberglass mil surplus poles for the central support, and a PVC tubing cap and SS bolts and wing nuts to hold the wire elements in place.  

     You can also simply erect a pair of low dipoles using two guyed PVC support masts.  For a quick and dirty demo system the wires needn't be more than 15 feet off the ground.  At this height, your 40M operation will be true NVIS (<< 1/4 WL off ground) and on 20M, that height is about 1/4 WL, almost high enough for a lower TOA than straight up.

     Drop me a note if you need more info.

73 de
Gene Smar  AD3F

From: "Falls, Jim" <Jim.Falls at conservation.ca.gov>
Date: 2007/05/25 Fri PM 01:58:00 CDT
To: Milsurplus at mailman.qth.net
Subject: [Milsurplus] Need TCS antenna advice

I have volunteered to show my operational TCS-8 system at an upcoming ARRL San Francisco Section annual convention at the Ferndale Fairgrounds 8 days from now (pitch, pitch). My question: what's a decent (AKA: quick up/down) antenna system I could use to work 40 or 20? I have found few details about the antenna this rig was designed to drive beyond a "low Z, 20 foot whip". I think folks would get a kick If I can get it up and running. 

PS: anyone have a spare ATU they would care to part with? Even just the 92 uH coil would be fine. Save me some coil winding.

Jim Falls
KG6FWT/AG
Eureka, CA

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