Antenna Adjustment at 20
meters Band: Above all, stay your K-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 place.
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.