Radial Detail
Posted on September 14, 2012
There are two specific opinions I presently hold regarding medium wave radials buried in the ground and fanning out from a vertical antenna.
There are two specific opinions I presently hold regarding medium wave radials buried in the ground and fanning out from a vertical antenna.
I am stating the opinions now as a way of checking them out, to see how much agreement or non that you may provide.
First, I believe radials must be done in even numbers, with a minimum of two.
“Two” in this case means that from the center-point, at the vertical, one radial points (let’s say) north, the other south.
In actuality these radials are a single long wire tapped in the dead-center by transmitter ground, thus defining a “stunted” dipole, whose two sides would be in opposite phase.
Every “set” of radials thus added to a circular area is a repeat of the stunted dipole, thus the need for even numbers of radials.
An unevenly numbered radial would extend from the vertical off toward some direction, but would have no opposite out-of-phase partner, and would thus either off-set the tuning, directionality, or possibly radiate.
My second opinion has to do with whether the radials are bare wire or insulated wire. Some writers have said that it doesn’t matter if radial wires are insulated underground, but I believe the insulation capacitively separates the bonding between dirt and wire. To say it the other way, I believe that wire to dirt contact makes a closer capacitive bonding than would occur with insulated wire.
I will appreciate your point of view on these matters.