Topband: Beverage on ground

R. Kline rikik at zahav.net.il
Sat Mar 6 09:15:43 EST 2004


Hi Paul,
There are 5 BOGs at 4X4NJ.  I have used 200 ohm terminating resistors, but
most of them are unterminated and work fine.  According to what is written
in the usual references, an unterminated antenna should give you about a 3
dB advantage in the usual direction (away from the fed end), but in
practice, I've found that this is more like 15 dB.  The transformers are 4:1
and consist of about 7 or 8 bifilar turns on a small toroid.  I forget the
number of the toroid, but you shouldn't have any trouble locating something
suitable - check in ON4UN's book on 160M DXing.  An added advantage (for me
at least) is that by having the antenna on the ground the velocity factor is
decreased, so it is. electrically longer than its physical length - even
more so than the typical Beverage above ground.  One word of caution.  From
what I've read, if your soil conductivity is high, the BOG will have
considerably less output than an above ground Beverage.  I don't know if
this is true or not practically because my 4X QTH has very rocky (poorly
conductive) soil.  At least for me, I will give the BOGs an "A".  They are
the best receiving antennas that I've ever used.  May I suggest that you
experiment by trying one BOG using the 200 ohm to 50 ohm transformer. After
using it unterminated, you might want to try terminating it.  Based on those
results, you will know if these antennas will work with your actual soil.
Please let us know the results.  One final comment.  The type of wire for
BOGs should be wire that can be trampled upon and is not easily broken.  I
use twisted pair military field telephone wire.  This is wire that was made
for the BOG application.  It is very rugged - having 3 strands of copper
wire and 4 strands of steel wire.  I short out the far end, and then from
the feedpoint, it is possible to check continuity with a simple ohmeter
check.  This gives the added advantage of the redundancy gained - even if
one wire were to somehow be broken, it would still work fine.  I've seen
this type of wire for sale at very reasonable prices on e-bay.  Perhaps some
of the usual surplus emporiums have it in stock too.  Also, don't forget
lightning protection.  That's another topic.....
73,
Riki
4X4NJ, K7NJ
----- Original Message -----
From: "Paul DeWitte K9OT" <k9ot at mhtc.net>
To: <topband at contesting.com>
Sent: Saturday, March 06, 2004 7:51 AM
Subject: Topband: Beverage on ground


> Because my beverages go through my pasture and get knocked down by the
> animals (and broke). I have decided to try laying the wire on the ground
and
> hope for the best (getting drug around etc).
>  For the people that use this or have tried this, do I need a different
> matching transformer? How about termination?  What if I chose not to
> terminate it, will that degrade it very much?
>
> Thanks 73 Paul K9OT
>
>
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