[MRCA] WWII German NVIS Antennas

[Gene Smar]

Dennis et al:

     The DDRR antenna (Directional Discontinuity Ring Radiator) is a horizontally-polarized antenna intended primarily for V/UHF work, although the initial development was for MF use aboard ships (or so I've read somewhere).  The dimensions needed (spacing above ground plane, ring diameter, etc.) are wavelength magnitude, not sub-wavelength as in the Wehrmacht mobile antennas we've been discussing.

     FYI, here are a couple of URLs: http://www.cq-vhf.com/AntennasFall07.html ,  http://www.arrl.org/members-only/tis/info/pdf/7112028.pdf .  Note that this latter article describes a DDRR for 40 meters, quite large for a DDRR.  

     In any case, I'm willing to bet that the NVIS antennae shown in WWII photos are NOT efficient NVIS radiators, but merely extremely compact, top-loaded short vertical whips.  Maybe someone can work with the MVPA and build a test antenna for demo at Gilbert some year.


73 de
Gene Smar  AD3F


From: W7QHO at aol.com
Date: 2008/06/24 Tue PM 04:34:30 EDT
To: al at ar88.net, mrca at mailman.qth.net
Subject: Re: [MRCA] WWII German NVIS Antennas


In a message dated 6/24/08 1:20:23 PM, al at ar88.net writes:


> That's a very insightful interpretation.  I guess I better start modeling.
> 

Model schmodle....    Why doesn't somebody try this kind of a lashup and give 
us all a report on how well/poorly it actually works.   I seem to remember 
something like this a number of years ago called a DDR Antenna?

Dennis D. W7QHO
Glendale, CA



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