Topband
[Top] [All Lists]

Re: Topband: Topband Digest, Vol 188, Issue 7

To: topband@contesting.com
Subject: Re: Topband: Topband Digest, Vol 188, Issue 7
From: Larry <lmwatbullrun@runbox.com>
Date: Tue, 07 Aug 2018 11:18:15 +0100
List-post: <mailto:topband@contesting.com>
 Mike K wrote in part >>>

Message: 2 Date: Mon, 6 Aug 2018 12:06:12 -0500 From: Mikek
<amdx@knology.net>

I have installed a 253ft Bog, ?I used WD-1A a pair and just twisted the
two wires together. Any reason I should separate the pair and just use a
single wire? Can the WD-1A be used for a Bi-directional BOG, or is the
spacing too close?

Mike:

Several things: 

  * I have tried bi-directional BOGs at my QTH and what I found with my
    ground is that the losses on the direction using the double wire for
    a return transmission line were very high, about 40 db or more when
    leaves got on the antenna. I got signal at the far end, but by the
    time it traveled back 250' along the parallel pair it had been
    significantly attenuated. Your ground may be different;  you may
    want to try Rudy Severn's ground test method using an 80 meter
    dipole to determine your ground characteristics, but at my QTH (WV
    rocks and highly conductive clay soils) the "return BOGs" were
    essentially useless, and I now use only unidirectional BOGs. 
  * As Guy noted, the ground characteristics can (and at my QTH
    defintely do!) vary significantly, and this is another hurdle to
    overcome which I suspect affects return line losses for 2-way BOGs.
  * As others have noted, ground moisture can make a huge difference in
    performance especially for some sorts of clay soils like those I have.
  * I did find that termination of the BOGs helps with F/B, and varying
    the resistance can change the pattern of one of my BOGs enough to
    help null 'town noise' from a town about 5 miles away.
  * getting the termination resistance right also helps with multiband
    operation by keeping the impendance excursions down so that the BOG
    works more consistently on 160, 80 and 40.

The things about BOGs that I like is that they are quick, cheap, easy to
install well, require no supports of any kind, and very low profile.

Regards and good luck with your BOGs!
LArry W8ANT

_________________
Topband Reflector Archives - http://www.contesting.com/_topband

<Prev in Thread] Current Thread [Next in Thread>
  • Re: Topband: Topband Digest, Vol 188, Issue 7, Larry <=