No Radials Needed

[flintstone mop]

A good Ham friend of mine, who has been SK, told me that if you string a 240 long wire vertically that you would not need a counterpoise at the base. 240 feet being a full wavelength???
Any truth to that??

Fred

[W7TFO]

Funny how this comes up every once-in-a-while.

Even a center-fed Franklin betters by having radials.

One thing is certain, at 240' it will need an obstruction beacon, sidelights, and an FAA registration number.

73DG

[KA2DZT]

A good Ham friend of mine, who has been SK, told me that if you string a 240 long wire vertically that you would not need a counterpoise at the base. 240 feet being a full wavelength???
Any truth to that??

Fred

Same thing is true at a half wavelength  You can save 120ft of wire

[AJ1G]

Half wave inverted L is also a high impedance antenna, you can get by with less radials than a 1/4 wave vertical or L, but you should use at least a few.  The GRC-9 field sets were designed to be capable of matching a nominal 1/2 wave random wire and work against a small set of counterpoise wires. The field antenna kit for the 9 was basically a set of wires with jumpers that were set up to approximate a half wave on the operating frequency, throw it up in the trees and away you go.  I have used a 1/2 wave wire with mine along with a couple of 1/4 wave radials and it played quite well on 40, worked all over EU on CW from out in the woods with that lash up.

[WB4AIO]

Vertically polarized antennas near the Earth have two kinds of losses associated with them:

1. Resistive ground losses when the Earth itself is part of the return circuit for antenna currents. These can be minimized by using long, higher radiation resistance elements or by having elevated radials instead of ground-level radials, or by having a large number of radials, or any of these combined. Contrary to the title of this thread, there is always some advantage in having a return-current set of radials or counterpoise -- though it can be quite simple: my 150-foot inverted L uses two opposed 50-foot radials elevated 8 feet above the ground and works very well.

2. Ground wave losses. These are not really losses, but might as well be as far as ionospheric propagation is concerned. There's no way to avoid these, since part of every vertically-polarized wave travels along the surface of the Earth, which is to some extent a conductor. These ground waves follow the curvature of the Earth and never reach the ionosphere. They are the basis of longwave and mediumwave regional daytime coverage.

73,


Kevin, WB4AIO.