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: [email protected] > To: [email protected] > 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 _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
