----- Original Message -----
From: "Guy Olinger K2AV" <olinger@bellsouth.net>
To: "ZR" <zr@jeremy.mv.com>
Cc: <n4zr@contesting.com>; <Topband@contesting.com>
Sent: Monday, December 05, 2011 3:42 PM
Subject: Re: Topband: Evaluating RX antennas
A reversible BOG does not work well because of the very lossy
conductors laying on the ground. It can be done but you need to run a
separate feedline to the opposite end and switch the feed circuitry in
and out. When you model it you won't get at all what you get on an
elevated beverage.
** Here we go again.
A reversible Beverage works very well on the ground if it is poor. Mine are
proof and are fed at one end only. Its knowing what your RF ground
resistance is and building the transformers accordingly that counts. ON4UN's
books and elsewhere are silent on the subject.
By ground I mean a typical forested path where the wire is supported by
ground cover growths and leaves. Mine wanders up to 6-8" at times until I
stomp it down during regular walks. I didnt run a CAT out back and scrape
down to the actual soil (-;
The endearing characteristics of a single two hundred foot -ish BOG
are 1) it seems fairly immune to neighborhood vertically polarized
noise, and 2) front to back. To check that simply see if W5 signals
drop down "a lot" on a NE BOG, etc.
** I see about a 15dB reduction of crud from a neighbor compared to one at
6-7' high parallel to it and about 12' away. F/B is the same at up to
20-25dB.
A BOG is quite lossy, not a gain antenna at all and almost always
requires an amp, best placed right at the BOG to create maximum signal
to noise distance from crap (usually from the house) on the feedline
shield.
** Strongly disagree again as you keep referencing your own experience or
some useless program that doesnt model those grounds worth a damn. My 500'
BOG's are about 3-6dB down from elevated at its peak, seems to be less
responsive to BCB groundwave by another 5-10dB, show no loss of directivity
and do not require a preamp on ham signals on 160-40M.
A BOG is really not a beverage. It's one member of a class of ground
low velocity factor RX antennas that is suggested by a beverage.
Getting an optimal pattern from a BOG does not follow beverage rules.
** A wire Beverage is a slow wave antenna and so is a Slinky or BOG version.
The effect of the ground is the deciding factor on useable length. A Snake
is not a true Beverage.
The original Beverage was on sand out on LI,NY.
Carl
KM1H
73, Guy.
On Mon, Dec 5, 2011 at 1:22 PM, ZR <zr@jeremy.mv.com> wrote:
> Put down another in the opposite direction. If you did a 2 wire reversible
> in the beginning it would have been easier.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Pete Smith" <n4zr@contesting.com>
> To: <Topband@contesting.com>
> Sent: Monday, December 05, 2011 8:10 AM
> Subject: Topband: Evaluating RX antennas
>
>
>>I just laid down a BOG and would like to evaluate its directivity. In
>> the absence of a calibrated signal source for real pattern measurements,
>> how do you go about this?
>>
>> --
>> 73, Pete N4ZR
>>
>> The World Contest Station Database, updated daily at
>> www.conteststations.com
>> The Reverse Beacon Network at http://reversebeacon.net, blog at
>> reversebeacon.blogspot.com,
>> spots at telnet.reversebeacon.net, port 7000 AND now
>> at arcluster.reversebeacon.net port 7000
>>
>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
>>
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>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
-----
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