Pierre Desjardins wrote:
Hi to all

I am thinking about using a Buddipole antenna on 20, 30 and 40 meters
with a KX1. What is the impedance range at the antenna that I can
expect at lowest SWR?

Also, I would be glad to try a .ez or .nec modeling file for this
antenna; if anyone have one, let me know. I use EZNEC +.

Thanks for your help

73 de Pierre VE2PID

Hi Pierre, As far as I can tell, the Buddipole is just a short loaded
dipole with the loading coils about 2-3 feet from the feed. Overall
length of the dipole is about 16'. On 40m the 2:1 swr bandwidth is
around 35-40khz. You need to tune it to the 40khz portion of the band
you want to work. On 30m it will be slightly wider, and on 20m
100-150khz. This is based on my measurments of Homebrew short, loaded
dipoles and verticals, and a lot of books on the subject.
You can model on EZNEC by doing a 16' dipole and placing an inductive
load at the point the Buddipole does, then an SWR sweep. Will give you
an idea what kind of bandwidth to expect. Your results will vary with
ground type, and heigth, but the Buddipoles I have seen in action are
about 10' up.
The efficiency of this antenna on 40m is low, but I have used one of
similar design with good results (100 watts).
73 Gary N4AST