Topband: BOG

[Guy Olinger, K2AV]

>> 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.