80 Meter Number 4 Vertical Antenna
I must have this thing for numbers as many of my antenna designs take the shape of
a number. This is my number 4 vertical for 80 meters. Physical form resembles a number
4 and it can be fed directly with coax. Original construction was accomplished by adding
approximately 40 feet of #14awg stranded copper wire to an already existing vertical
that is 16.47 feet in height. The vertical is made of telescoping aluminum sections (see
my 30-10 meter vertical. The vertical is in the 20 meter configuration.)
Tuning is achieved by adjusting the gap between the vertical and horizontal sections.
A change of one inch produced a change of 200Khz in resonance. SWR is 1:1.5 across about
75Khz with a usable SWR bandwidth of about 150Khz. By adding the auto-tuner from my Kenwood
TS-570 the SWR is under 2:1 across the entire 80/75 meter band. This antenna is very
experimental yet with much work to be done. I have made no official measurements with
test equipment other than the SWR meter.
My first QSO resulted in a 599 signal from a station in NC. My second QSO netted another
599, this time from AR. Both contacts were made after dark using no more than 5 watts on
PSK31. Unfortunately, a wind storm that night took out the temporary installation and I
have yet to re-construct the antenna. I plan to model the antenna and conduct more
experimentation with its use.
