Dan,
The simple Left/Right Doppler systems work well and are very
inexpensive. However, they require a FM detector and normal aircraft
walkie-talkies are AM. Many of the modern amateur radio walkie
talkies have extended receive coverage and can receive FM on aircraft
frequencies. Some have AM detectors for receiving normal aircraft
transmissions.
You might check with the local Civil Air Patrol which is populated
mainly with hams. They may already have the receivers.
The Left/Right systems also work well on aircraft. You fly the plane
in the direction indicated by the null. You are either flying toward
the transmitter or the exact opposite directing. Fly perpendicular to
the indicated direction a short distance and read the direction again.
This will eliminate the 180 degree ambiguity.
A number of these systems have been described in amateur radio
magazines. The antennas are quite trivial. Since you are concerned
with only two frequencies, there are complete systems sold with a
crystal controlled receiver. They are easily transported, weighing
only a few pounds.
73, Barry L. Ornitz WA4VZQ ornitz+AEA-tricon.net
Received on Fri Apr 30 1999 - 06:07:30 EDT
This archive was generated by hypermail 2.2.0 : Sat Oct 02 2010 - 00:10:39 EDT