Topband: BOG height

[Guy Olinger K2AV]

Hi, Ed,

You're on the right track.

A "beverage" ON the ground really is NOT a beverage.  For two things to be
called the same genus, they need to have most everything in common. This is
true of big yagis, little yagis, short yagis, long yagis, trapped yagis,
linear loaded yagis, end loaded yagis, moxons, yagis at 30 feet and yagis
at 200 feet, etc. One program optimizes them all. A yagi is a yagi, is a
yagi, is a yagi, and all of them have a ton of yagi-ness held in common.
Simply not so BOG vs. beverage.

Creating beverage advice from one particulars person's wire down close to
or on the ground at their particular property, may be simply and totally
wrong for someone else. The normal beverage tuning instructions, usually OK
for wires a foot off the ground and maybe even OK to some degree for four
inches, simply do not apply if the wire is actually laying on the ground.

A regular beverage has a decent RX signal strength. To be truthful, a
**real** BOG needs a remote amplifier, because its output is way down from
a real beverage. Get this much straight: an actual BOG is a LOW output
antenna, period. The way to improve a BOG's signal output is add an amp
(best remote), or escape BOG-iness and lift it off the ground.

If you model a real BOG, you find that beyond an ELECTRICAL half wave ON
THE WIRE, or two hundred something feet on 160, extending the BOG wire will
start to REVERSE the pattern. No real beverage ever does that. Just some
beverage lengths are bit better than others FOR REAL BEVERAGES. A BOG is a
single band antenna for optimums. It will hear stuff on other bands, but
forget a designed pattern like you have on a beverage for several bands,
that work WELL on several bands.

If you are even two inches above actual ground, laying on top of grass, you
are blending the very different worlds of pure BOG and pure beverage. If
you are at two inches, you are at a poor place to advise either owners of
pure BOG's or pure beverages. The great problem is that exactly which type
you are closer to depends on the vagaries of the location-specific ground
underneath.

These vagaries wander HUGELY ( I'm talking about an actually carefully
****measured****  wandering HUGELY) depending on individual properties.
Based on those **measurements** it is a normal outcome that one end of the
wire could be more BOG and the other end of the same wire could be more
beverage, and even vary more depending on whether it rained in the last few
days (or weeks depending on the local and natural drainage of the soil).

It is clear reading a lot of the posts on BOG's from the last week or two,
that a lot of users were expecting greater signal output. Don't. A REAL
*BOG* that was laid down, notched in the grass down to the actual ground
surface, to get it out of sight and safe from lawn mowers, WILL sound MUCH
better to the ear if it has an amp. Otherwise, a BOG is a LOW LEVEL RX
antenna.

IN GENERAL, a real BOG needs an amplifier, will usually wind up somewhere
180 to 230 feet if you want front to back, and it's great advantage is that
it can't be mowed, snagged by galloping deer, have tree branches knock it
down, be seen by unfriendly neighbors and it will do roughly as well as a
single direction K9AY, but without the AY's ugly wires above the ground, IF
it's amplified. If the feed circuitry is done correctly, a BOG will be
wonderful at reducing local noise off the sides.

You will increase signal level significantly by getting it up an inch or
two on top of the grass, but it ain't a pure BOG anymore, the VF is
increased significantly, and then it needs more length to be optimum at two
inches. And you will still not be able to tune it smartly like a beverage
using SWR to the terminating resistor.

BOGs are a cantankerous RX antenna. You can throw a 250' wire down on top
of the lawn and take it up after the contest. In normal (not super quiet)
settings it WILL hear a lot of signals better than the inverted L. Just
understand that is NOT a design antenna, and was not optimized, did not
have the best signal to noise of a designed-for-location BOG antenna, and
was not as good as a beverage.

We know what the issues are, but new-comers to the BOG idea just don't know
the vagaries and how to squeeze the best out of on THEIR property.

The category is Ground Low Velocity Factor (GLVF) antennas. DOGs, LOGs and
BOGs. If they're up in the air, even two inches, they're likely NOT GLVF.
GLVF are low output RX antennas. If you are looking for high signal output
from the antenna without an amplifier, just forget GLVF.

Been there, done all of that.

73, Guy K2AV


On Thu, Aug 1, 2019 at 2:57 PM Ed Sawyer <sawyered at earthlink.net> wrote:

> Isn't  BOG still a beverage just with more ground coupling loss because its
> literally "on the ground"?  So the typical answer on beverages seems to be
> that 4 - 10 ft above the ground is low enough to eliminate the undesired
> noise but high enough to reduce the losses from being too low to the
> ground.
> A BOG is a beverage with higher than desired losses.  But if its long
> enough, pointed in the right direction, and your ground conductivity is
> accommodating, its less of a trade than the reverse of those items.
>
>
>
> I have had a few unplanned BOGs that were discovered as "on the ground"
> because of some supports falling down.  I could immediately hear the
> difference, but they still worked.  Would they be usable if that was my
> only
> option?  Sure.  Just not as good as the same wire at 6 - 8 ft.
>
>
>
> I use 650 - 1000 ft terminated beverages and they are quite amazing.  My
> ground condition is lossy and I don't have much local noise to null out.
> Its pretty much all atmospheric noise.
>
>
>
> Ed  N1UR
>
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