Bob,
Harold Beverage was from North Haven Island, nearby here in Maine. I have
done extensive research on the Belfast, Maine Atlantic Ocean, Radio Relay
station that started spring 1923 by the Radio Corporation of America.
The (average 18 foot) above ground Moody Mountain Beverage had a lot of
Buried #10 copper wires. (South Searsmont end of the "10 mile" Wave
(Beverage) antenna.) Harold Beverage was the overall Engineering supervisor,
H.P. Hassner the site start up Engineer.
Also in 1923 Clarence Hansell performed wave antenna testing for
transmitting compared against a vertical with Riverhead, N.Y. Hansell's
actual length measurement of the Moody Mountain wave antenna was 52,610
feet. Hansell, then installed a separate shorter wave antenna using 5/16
inch copper wire with a counterpoise beneath. Test were ended when
the shorter wave antenna came in well below the test vertical signal
strengths. (Hansell's Belfast log book is available through Stony Brook
University)
The Moody Mountain wave antenna actually terminated in Black Brook at the
base of Moody Mountain and they had runs of buried wire going into the
water. (Fresh water was thought to be more conductive, when water surface
froze, the wires were in the mud below.)
My research on BOGS, I found that the termination resistor did not cancel
all the signal pickup from a radial. I also found that as a BOG became too
long it self terminated and the pattern became unpredictable. I believe it
was the capacitance to ground vs the frequency, a bypassing function.
Although I have not measured the pattern, by transmitting a weak signal into
it, on air testing comparing signals against verticals, indicated general
directivity held until the BOG was too long and self terminated.
I found by removing my 300 ohm termination resistor, and re-sweeping the
antenna, I could see the frequency which self termination took place. I
shortened the wire length enough times until my lower bands were being
terminated by the 300 ohm resistor. (had to re-drive the termination ground
rod a few times) The best BOG length varies with wire size, insulation,
ground conductivity, actual closeness to ground. (I am up an inch or two, in
some places, as it goes along the run from vegetation)
73
Bruce-K1FZ
> I used lots of BOGs (but only for 160) and found that Harold
> Beverage's advice (for normal Beverages) recommending a few short
> radials laid on the grouind and symmetrical, applied to the BOGs too,
> except that if the BOG was long enough we didn't need any termination
> at all at the far end.
> I also found that for resonant 160 antennas, 1/4 wave long elevated
> terminating wires were better than any ground rods, winter and summer,
> rain or shine, Rx or Tx. Our temp only goes down to -25C or so, but
> frost goes to about 50 cm deep sometimes.
> Bob VE7BS
>
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