Topband: [bevantennas] Ground screen under beverage....

[Grant Saviers]

Worse than "not the best" or "not a good idea" from prior 
experimentation.  My two Beverages 6 feet up (10' total Z) over a 4 
strand barb wire fence did not work - very poor directivity.  One N-S 
and one E-W. Then some NEC2 modeling showed 6db directivity over 3 
strands of barb wire.  However, insulating all fence wires below a 600' 
Beverage in 4 places, at ends and at 200' & 400' showed modeling 15db 
directivity and 2 more db of gain.

Some good news was the modeling showed 1000' of continuous fence beyond 
the ends had no effect. I sold the ranch before insulating the fence. (+ 
PITA to do it).

Beverage theory agrees with the modeling and experience, so it was a 
learning experience for me.  Ran the models again with NEC4.2 and got 
the same results.

So I learned to not have conductors parallel or nearly so in close 
proximity to a Beverage and that the modeling made sense.

Grant KZ1W

On 10/1/2020 15:34, Mike Waters wrote:
> Gentlemen,
> 
> I am in full agreement with the many statements that Vic Misek's design (at
> least in the first edition of his book) is, uh, 'not the best', and a
> ground screen (or grounded wire) under a Beverage is 'mostly' *not* a good
> idea. Over 40 years ago I was going to built it, but W8JI himself told me
> in uncertain terms that it wasn't near as good as a 1λ Beverage (or
> something to that effect. ;-)
> 
> However, in recent years it occurred to me that a wire or narrow ground
> screen under a Beverage *might* not completely ruin its usefulness in all
> types of soil, because the Beverage still "sees" the lossy earth on either
> side of it to some(?) extent.
> This is merely an untested theory of mine, and I have no idea whether there
> is any case to be made for it.
> *Most of all*, I know of no one who has performed technically-sound,
> side-by-side instantaneous A-B F-B, RDF, etc. comparisons. I think this
> might be what Jay is thinking about.
> 
> I also have heard that Vik has posted revisions to his design in newer
> editions. But I am not qualified to say if they are better or not. An
> advanced NEC 4.2 model would be better than nothing
> 
> Also, Vik's design *might* not be working as a true Beverage, but rather
> something along the line of the many different compact receive antennas.
> (The K9AY and Shared Apex array are all that come to mind, but I'm not
> saying that there are any similarities to either of these.)
> 
> Much has been written by Beverage experts in the Topband reflector
> searchable archives about this.
> http://lists.contesting.com/archives//html/topband/
> We would do well to study them.
> 
> 73, Mike
> W0BTU
> https://web.archive.org/web/20181115070846/http://www.w0btu.com/Beverage_antennas.html
> 
> 
> On Thu, Oct 1, 2020, 3:41 PM Jay <jay at jasonh.com> wrote:
> 
>> ….But my Beverage is 4 feet above the ground. In the new configuration, it
>> will be 6 feet above ground.
>>
>> Would a ground screen benefit a Beverage antenna that is 6 feet above
>> ground?
>>
>> *From:* bevantennas at groups.io <bevantennas at groups.io> * On Behalf Of *Walter
>> Salmaniw via groups.io
>> *Sent:* Thursday, October 1, 2020 4:14 PM
>> *To:* bevantennas at groups.io
>> *Subject:* Re: [bevantennas] Ground screen under beverage....
>>
>>
>>
>> I can add my $0.02 as well.  I run BoGs in Masset, with lengths up to
>> 750'.  I've tried counterpoises as well.  The wire lays on essentially
>> sand.  I have not noticed any value to having multiple counter-poises in my
>> experimentation.  I've tried 2 types:  1 is a single wire upto 100' in
>> length, and the other experiment was a fan of counterpoises of about 30'
>> each.  Didn't do much of anything, best I could tell....73,  Walt
>>
>>
>>
>> On Thu, Oct 1, 2020 at 8:08 AM <nhp at ieee.org> wrote:
>>
>> Hello Jay,
>>
>> It seems to me that there was some disagreement with Misek's idea of using
>> a counterpoise under a Beverage antenna, based on the principle that the
>> Beverage antenna works best with a poor ground underneath it.  Effectively
>> improving ground conductivity under the wire seems counterintuitive.
>>
>> I probably have some notes in old file folders on such experiments that
>> were done back in the 1970s and 1980s by hobbyists, and I'm sure that I've
>> tried at least a wire counterpoise myself, but that it didn't seem  to be
>> worth the extra trouble. Otherwise I'm sure that I would have continued
>> using it in my DXpeditioning days.
>>
>> The medium wave club, IRCA (ircaonline.org), has a number of reprints,
>> including some on Beverage antennas, and hobbyist experience with them. The
>> club is presently in the process of making those available to the general
>> public, so keep an eye on their website.   It should happen in the next
>> month or so.
>>
>> best wishes,
>>
>> Nick
>>
>>
>>
>> At 04:01 2020-10-01, Jay wrote:
>>
>> Hello all,
>>
>> I currently run a 320 foot long beverage using the DX Engineering balun
>> and resistor. Both ends are grounded with an 8 foot ground rod. I am
>> getting good results, but I want to improve the antenna. I was reading "The
>> Beverage Antenna Handbook" by Victor A. Misek, P.E. W1WCR, and he talks
>> quite a bit about ground. What I want to do is lay a ground screen
>> underneath my beverage- (1x2 inch by 6 ft wide) welded wire. I will connect
>> the ground at both ends of the antenna to this ground screen. Additionally,
>> I am using plastic fence posts from Tractor supply to hold up the antenna
>> currently. (4ft high) the bottom 6 inches is metal. What I want to do, is
>> pound an 8 ft ground rod in, and connect that to the ground screen every 10
>> feet or so, and then leave 2 feet or so of the ground rod exposed. That
>> way, I can use a hose clamp, and attach the fence post to it, for a more
>> permenant installation.
>>
>> Have any of you tried using a ground screen underneath your beverage to
>> improve the directivity, and lower the noise floor of your antenna?
>>
>> I would love to hear comments on this idea.
>>
>> '73,
>>
>> Jay
>>
>> Nick Hall-Patch
>> Victoria, BC
>> Canada
>>
>> _._,_._,_
>> ------------------------------
>>
>>
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