>> I would like to ask beverage guru's over here if somebody using BOG
>> successfully or if somewhere is chart of the functional BOG as I heard
>> about that
>> solution mostly negative feedback.
>> 73 - Petr, OK1RP
I would guess that most negative press on BOG's originates first with them
being a lot quieter overall, both noise and signal. Then in a/b switch tests
the regular beverage seems to "outperform" the BOG by huge margins. I have
seen just a very few comparisons that said the signal-to-noise on the
beverage was X and and on the BOG for the same signal was Y.
The only way to do good a/b switch testing is to first add a variable gain
preamp on the BOG to bring up the background noise to the same level as the
reference beverage. BOGs are lossier than beverages. Then and only then,
desired signal levels on a/b switch tests will mean something. With BOGs
and beverages we are trying to improve receive signal-to-noise using antenna
pattern, the opposite of trying to get maximum gain out of transmitting
antennas.
Cons:
BOGs need preamplification, either preamp switched on in the transceiver, or
a separate RX preamp.
BOGs change significantly with the dampness of the earth which in turn
affects velocity factor. If they seem off and the ground is dry, pre-contest
soaking the ground (+/- two or three feet) with a garden hose seems to
brighten them up. Walking the BOG line while pouring out of a bucket also
works. (Hence the dubious local joke, walk the boggie.)
Long single BOGs don't work as well as two shorter parallel BOGS. This is
because measured velocity factor of wire on the ground can go below 50%.
Regular beverage formulas and assumptions work poorly for BOGs.
The factors generating patterns from BOGs are quite different than
beverages, and modeling them requires working in an extreme velocity factor
and ground situation which I've only been able to do correctly in NEC4.
One must use stuff that critters don't like. Teflon sheathed wire, flooded
RG6 feedlines, etc.
Pros:
Laying on top of the grass, vs being buried just a bit like radials does not
make much difference, so BOG arrays can be hidden in the turf given
attention to waterproofing and critters.
One can't trip on buried BOGs.
BOG elements have very little mutual coupling due to the ground next to or
around them. There are BOG arrays that can be constructed which will not
work above ground.
That the signal on the BOG wire is only travelling 50 to 75% as fast as the
free-space exciting wave, can be used to advantage in some designs, (while
rendering others ineffective).
I've not seen much published. So who knows what neat design is waiting to be
dreamt up. BOGs are pretty much the undiscovered country.
73, Guy.
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