One other thing to do is to use more than 4 wires (multi stranded computer
ribbon cable say) and cut them to suit the whole spectrum of frequencies you
will use. This way at least your ground plane will be more closely tuned..

Running the wire at different angles will also vary the impedance (50 ohm
required for a 1/4 wave) so again the different lengths will get you to a
much closer result..

Malcolm...



"Tim Mara" wrote in message
...
please see my page http://www.wingsandwheels.com/page14.htm
The basic math for 1/4 wave antenna is quite simple
1/4 wave = 234 divided by frequency or to arrive at a proper antenna
length. As an example for 123.5 would be 234 / 123.5 = 22.8"....this
length should however also take into effect the distance from the ground
plane to the antenna mast tip. Considering this though an antenna cut for
118.00 would be 23.88" and one for 136.00 MHz would be 20.64 so the total
difference is only just over 3" to cover the entire aviation band and 1/4
wave antennas are fairly tolerant and will function with fair results
several MHz off from the "ideal" antenna length.

tim

--
Please visit the Wings & Wheels website at www.wingsandwheels.com


wrote in message
...
I am installing a regular rod type antenna on the wooden turtledeck of
my plane where it will attach to only wood. I got the antenna from a
friend who didn't have the attaching hardware.
Do I need to do or know anything special to attach this antenna to
make sure it operates correctly? Does it need to have a metal plate
on the inside of the airframe to attach to or does it need to somehow
be connected to the metal part of the airframe for proper reception/
transmission? Can I just use local hardware store parts?
I will be running the cable to my handheld radio.
Thanks for any assistance.
Stan
(mechanical novice)