Antenna Adjustment at 20 meters Band: Above all, stay your Ê-1 to 2W. Antenna (spiral at first it is not spreading
by the stick) is connected to K1 by a small (50- 70 cm) length
of a coax. A small bulb
is connected in serial with the spiral. I have used a bulb from
a toy gun feeding from 3V. Turn on K1 to receiving mode to the
20 meters. With help of a dielectric stick (I used a length of
a plastic water pipe) in 1 meter length lift upwards the spiral.
Find off the spiral length when you have the best reception. Do
a hole in the stick at the length and pass through the hole the
end of the spiral. After that once again with the help of the
dielectric stick, approximately on the length of 2/3 (from spiral
length) from the antenna bottom, lift or lower coils
of the spiral by the best reception. Coils are fastened by Scotch
at the proper place. After that you may turn on K1 to transmitting
mode (for a short time) and to make final adjustment of the spiral
(by max glow of the bulb) at the length of 1/3 (from spiral length)
from the bottom. Coils are fastened by Scotch at the proper
Antenna Adjustment at 17 meters Band:
Prepare a 60 cm length insulated wire (18 AWG) with crocodile
clips at the both ends. Connect
to K1 the antenna and turn on it to RX. Short different parts
of the spiral by the best reception.
Antenna hung up to eave
Fastened the Spiral to the Form
Turn on K1
in TX and check the antenna by glow of the bulb. Put marks by
marker at the shortened coils.
You can turn on the wire to the marked coils when work
at 17 meters band.
1 shows a final design of the helical antenna. Short
the bulb by a crocodile clip when you want work to transmit or
you lose RF power in the glow bulb.