Austin Amateur Radio Club has many years of Field Days using bi
directional V beams of 10 waves on 10m. Mostly, we used them on 20m and
find they are similar to rhombics with easier construction. You only
need three supports vs. four for a rhombic. The problem re FD for
either type of antenna, is you can erect it too high, ie if erected 1/2
wavelength above earth at the feedpoint, you will have a good DX
antenna, but the first skip from Central USA falls well beyond most of
the FD population. They make a good coast to coast skip if erected only
10 feet high, and were a lot of fun with QRP, as your signal often was a
dominant one on a band. (Or so we were told by a group in Maine!)
The narrow beam of the Vee beams as we implemented them, gave us an
angle of about 40 degrees. Thus, we had to erect 3 Vee beams to cover
most of the country. The unterminated Vees were bidirectional, thus the
one opening to the NW could work SE.
For FD use, we actually got better coverage with a 2 wave horizontal
loop for 80m used on 20m. You could work the closer states you could
not work on the Vee beams. Vees and Rhombic take so much wire and time
to erect, that we have given up on the labor intensive, and do things
like Double Extended Zepp inverted Vee doublets, and NVIS low dipoles to
cover more territory.
My personal experience with Rhombics was at Ft. Sam Houston, TX, with
old Signal Corps pre war Rhombics the Fourth Army MARS station inherited
about 1961 or 62. Great DX antennas when on a hill and high tower.
Definitely more of a point to point pipeline, than for working random
QSO's. Hugely fun with a KWM2 and AM or SSB.
-Stuart Rohre
K5KVH
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