R: Topband: BOG antenna notes

[Giulio Scaroni]

Dan, is about 3 years that i use a BOG for improve the reception on 160.
This year i have a pair of phased BOG, one is on JA is more than 1000 feet
long, and the wire are spaced about 5 meters, the other is on VK6 area and
is long more than 750 feet, also this is 2 wire phased.
So the impedence here of the BOG is not so low like many books and articles
report, here the impedence measured with a impedence bridge report impedence
more than 300 ohm for the single wire version.
Here i have a very good ground in my location, the Pianura Padana (I2).
So the output is a little bit lower than the 1 meters hig beverage, so in
same situation is better a little high performance preamplifier.
The only prolblem is the the BOG have a low velocity factor, so longer BOG
do not produce the same signal produced with the higher version of
beverage!! (like report V.A. Misek on "The beverage antenna handbook).
Here i have also a 900 feet high 1 meters beverage on the USA, and 1500 feet
long beverage 2/3 meters high on 20° nord, that i have used many times for
receive the JA signal when the auroral activity is low and the signal coming
from the North Pole, or UAO, like UA0MF from east Siberia.
But this 2 last are much much noise than the lower BOG.
Ahh, i was forgetten, like the hig beverage work well on all the bands, here
the BOG seems to work very good only on 160, on 80 and on the higher band
they are dead.

73 to all, and see you on 160!

Giulio IK2DED.


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