To add to the open-sleeve coupling notes, there is an open sleeve coupled
12-17 design for back-to-back 2-element DE-Dir beams for 12 and 17 at my
site under the Upper HF antenna notes. Since the WARC bands are narrow, a
close spaced DE-Dir design is practical, since it will hold its properties
for the 100 kHz width of the bands--as well as its feed Z. The open
sleeve coupling idea means a single feed (17 meter) which requires a beta
match. The 12 meter DE should then be adjusted in spacing for a 50-ohm
impedance at the 17 meter feed terminals, with the Dir spacing on 12 held
constant to its DE. This Janus-faced beam uses about a 10' boom and
provides better F-B than DE-Ref 2-el designs and can be made from readily
available stock.
Hope this is useful.
-73-
LB, W4RNL
L. B. Cebik, W4RNL /\ /\ * / / / (Off)(423) 974-7215
1434 High Mesa Drive / \/ \/\ ----/\--- (Hm) (423) 938-6335
Knoxville, Tennessee /\ \ \ \ / / || / (FAX)(423) 974-3509
37938-4443 USA / \ \ \ \ || cebik@utk.edu
URL: http://web.utk.edu/~cebik/radio.html
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