A toroid coil antenna for 20 and 40 meters
This evening I tested out a new antenna.
It is a 33-foot end-fed halfwave for 20 and 40 meters. On 40 meters
there is a pair of coils. They are made with three T80-2 toroids
stacked and wound with 36 turns of 22-ga enamel wire. The coil on the
left shows the setting for 40 meters. The right coil is set for 20
meters by bypassing the coils with an alligator clip lead. Of course,
they would both be set the same while operating. I read somewhere that
the toroid coils peform poorly when wet, so I coated them with
"Liquid Electrical Tape." The total weight of the antenna is 4 ounces.
The antenna itself is made of 20-ga stranded, insulated wire.
There is 11' 2" of wire between the coils, and 7' 5" of wire
on both ends.
This dark photo shows the setup this
evening. On 40 meters I worked Hal, K5NOW, in Arkansas and Brian,
W9BRE, in Wisconsin. The first station reported my signal was 599, and
Brian gave me a 559. Not bad for 11:30 p.m. and surrounded by trees,
houses and power lines. I am also in a valley surrounded
by mountains. The antenna is supported by an MFJ 33-foot pole.
Even though it was late, I switched over
to 20 meters ssb and immediately worked a contester, N7DD in Tucson,
AZ. That was after midnight here in Colorado! Twenty meters was in good
shape. I heard DX contesters but unfortunately never broke the pileups
with my QRP station. There was VK4WIA, ZX5J, TG9ANF. . . The
Australian station was coming in 5x8 around midnight local time.
The table shows my FT-817, a 4.5AH battery, and my Palm CW paddles
taped to the plastic table. They have a magnetic base and are meant to
be used on top of the radio. In the background is the PVC base for the
antenna, and the homebrew matching unit can be seen taped to the pole.