Designing A Rubber Resistor
 

Most of us have done the old comparison between a standard "decent" antenna and
the rubber resistor most manufacturers use on their 2-meter HTs. I've seen
anywhere from 10 to 25 dB difference even IF I use the same groundplane
configuration for a "real" groundplane and the rubber duckie working over the
same metal structure.

My goal is to wind up with a foreshortened antenna on the order of the size of
the duck that comes with the HT, but a bit more efficient. I couldn't care less
about multiple bands with a single antenna, but I would like some decent
bandwidth.

I've visited Reg's wonderful site and made some quick and dirty calculations
using his programs, but most of them seem to be slanted towards HF antennas over
a dirty ground, and I'm not really sure what to expect using a VHF antenna over
a metal ground plane.

I'd like to do some more calculations and some more configurations before I
start bending and winding wire haphazardly, but there is a notable lack of
information on foreshortened VHF antennas on the web and in the literature. If
anybody can point me in the right direction, I'd be most appreciative.

Jim


Jim Weir, VP Eng. RST Eng. WX6RST
A&P, CFI, and other good alphabet soup