With the caveat that I am not any kind of SME on 160 meter antennas, I would
be surprised that you'd need much of a counterpoise for an End Fed Half
Wave antenna.
My experiences with an End Fed Half Wave antenna show that a small (small as in
length of a singular wire) counterpoise is all that's required. Assuming the
physics for an 80 meter or 40 meter EFHW antenna carries over to 160 meters I
don't see the need for anything of length or numbers - for my 80 and 40 meter
EFHW antennas I use about 3 feet of counterpoise....I've lengthened that wire
up to a 1/4 wave and have noticed zero improvement in SWR or received signal
strength at several RBNs.
72, Jim Rodenkirch, K9JWV
> From: k3ky@radioprism.com
> To: topband@contesting.com
> Date: Tue, 15 Nov 2011 22:15:04 -0700
> Subject: Re: Topband: contesting in a field
>
> I like resonant, voltage-fed verticals for their simplicity. For field
> ops,
> they can be a very quick way to deploy a working antenna. On 40 meters,
> for example, you're only dealing with 70ft- or 35ft if bent like an
> "L",
> Half Square, Bobtail, etc.
>
> If you could catch Murphy on vacation, and if you can raise a large
> enough balloon to support ~268ft of smaller gage wire, you can go with
> a voltage fed half wave using an LC tank to tune it. Tap up the coil
> from the ground end with your coax for a 1:1 SWR (assuming your LC is
> properly resonated) Your farm isn't near any airports, is it? OTOH if
> it's windy, this could be a rather frustrating event. (technically,
> you're 'pushing it' a little with anything over ~200ft in height)
>
> You don't need much of a counterpoise, feeding this way- roll out
> however much chicken wire or wire cloth as you care to- or think
> 'radials', if that is your preference. A denser, shorter radial field
> or counterpoise ought to work pretty well.
>
> Having the current max up 134ft couldn't hurt. It ought to play
> reasonably well. As always, more ground is better ground. I like
> the roll(s) of chicken wire approach.
>
> 73, David K3KY
>
>
> >The last thing I need is a reason to generate flammable gasses in bulk :)
> >
> >We homeschool, so maybe that would fit the stereotype everyone expects.
> >"And then they did a chemistry experiment and blew up their garage."
> >
> >I've thought about an inverted L at home, I have just short of an acre, I
> >think the above ground part wouldn't be a problem its the radials. I'm
> >assuming in the wide open spaces at the farm I can pursue the same elevated
> >radials I would for a kite/balloon vertical? The elevated vertical thing
> >seems to be the best bang for the effort, and in some ways less effort
> >especially for temporary ops like this.
>
> Chris
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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