HALF-WAVE DIPOLE ANTENNA
The half-wave dipole is the easiest and cheapest antenna to use if space is available for it, requiring only whatever wire can be obtained [small lengths can be twisted and soldered together to make the required total length] and enough coaxial cable to connect it to the station. No antenna tuners or SWR meters are needed for great performance.
to calculate the
length of a half-wave dipole antenna:
L= 468/f
L = total length of
dipole in feet; and
f = frequency in MHz. 
Dipoles can be combined for
multiple bands. Illustrated above is
a simple multiband dipole
antenna for 80 and 40 meter operation KC6WDK used with great success. The 40 meter section also
permitted use on
15 meters. The sections were separated by 2' at the far ends of the 40 meter
elements. The antenna was made from scrap lengths of insulated wire with the ends
twisted together. The 50-ohm RG-58 coax lead-in was coiled at the feed point to form an
optional broadband choke balun which prevents antenna currents from flowing back into the
transmission line. Despite the scrounge-and-improvise construction and
although only 12 feet off the ground, this antenna performed very well.
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