One way to move up the "sweet spot" on a BOG that has been "mushed down" is
to go to the center of the BOG wire and carefully pull the wire up from its
mushed down position a few feet at a time. Pull up just a few feet at a
time and recheck the sweet spot each time until you move it back on
frequency. Increasing distance from ground increases velocity factor and
shifts performance spots up in frequency. Don't try to pull up a bunch at a
time, you'll overshoot the target frequency.
My loops-on-ground have to be pulled out from under the wet rotting leaves
annually.
73, Guy K2AV
On Monday, May 18, 2015, K1FZ-Bruce <k1fz@myfairpoint.net> wrote:
>
> I receive questions from those who try for direct comparisons to a
> Beverage antenna. There are a few that have put the time in to find how the
> BOG antenna works. K2AV, Guy also has taken time to get the facts.
> Because of the closeness to the earth, the BOG velocity factor is often
> below .5 This can result in overall lengths of ~ 200 feet.
>
> My latest BOG is a two wire, two direction with 200 feet of wire. the
> best, (excellent), F/B when first installed was at low end of 160 meters.
>
> Now in the 2015 springtime, after a tough winter, the best front to back
> is in the upper Broadcast Band. There is one frequencies where I can get
> two radio stations, out in the clear, just by switching to the opposite
> direction.
>
> The reason my BOG frequency went down in frequency is the large amount of
> vegetation packed down by the near record amount of snow, has lowered the
> velocity factor.
> The only question is now, do I shorten the BOG wire, or just pull up
> 200 feet up out of the vegetation ?
>
> 73,
> Bruce-K1FZ
> www.qsl.net/k1fz/bogantennanotes/index.html
>
> Also check out www.contesting.com/_topband
> search BOG antennas, K2AV, and K1FZ
>
>
>
>
>
>
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
--
Sent via Gmail Mobile on my iPhone
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|