Vectronics VEC-1120K - Manual (Page 29)

VEC-1120K/1130K/1140K/1180K Instruction Manual
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simple to make, and are very effective antennas. For QRP work, or for receive
only applications, low-cost RG-58 52-ohm coax is fine. CATV 75-ohm cable,
such as RG-59, will also work well.
The formula:
234/(frequency in MHz) = 1/4-wavelength in feet
will give the length of wire needed for each leg of the dipole. For example, a 30-
meter dipole cut for 10.120 MHz would use two wire legs, each about 23.12 feet
in length.
Wire legs, 23.12’
i nsulators
Coax cable
30-meter dipole
An alternative antenna for 80, 75 and 40 meters is a ¼-wave wire antenna. The
wire antenna is connected directly to the receiver. For best results, a good
ground is needed when using a wire antenna.
¼-wave wire
23.12’ at 10.12 MHz
Ground wire to ground rod
30-meter wire antenna
Receiver
Overload and SW station bleed through: An unfortunate fact of life is that
low-power Amateur signals are surrounded by high-power SW broadcast signals.