They were around somewhat before the patent in several forms, and they
were around in 1960, which is the last time I looked hence my estimate
of 60 years. Lots of other "balanced" antennas fed with open line were
also in use commercially during that rough period, they too exhibited
the same characteristic ... while carefully engineered to be balanced,
RF currents in the two wires never were exactly balanced, which was the
original and only point.
I still have an RF ammeter in my junk box, from some airborne WW2 radio
I think. It's probably an antique by now.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 7/16/2020 5:47 PM, donov...@starpower.net wrote:
Hi Skip,
Conceptionally you're correct about rhombics and V-beams but your time
frame is way off.
Edmond Bruce's rhombic antenna patent was filed in 1931.
www.aktuellum.com/mobile/circuits/antenna-patent
<https://www.aktuellum.com/mobile/circuits/antenna-patent/>
ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1685103
<https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1685103>
The heyday for the rhombic ran from the 1930s through the 1970s with
the advent of satellite communications. The 200 foot tower for my
40 meter stacked 3 element Yagis came from a decommissioned
Laport Rhombic installed at the NSS receive site in Cheltenham MD.
We removed it in 1985, but it hadn't been used for years.
73
Frank
W3
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