THE ALL BAND HF
The all band doublet
antenna is nothing more than a 1/2 wave dipole cut for
your lowest operating frequency and fed with twinlead, ladder line,
open wire, etc to a tuner that will accept a balanced line connection.
It can be designed for use from 160 thru 10 meters very easily using the standard 1/2 wave dipole formula:
total length (ft) end to end
If you don't have room for the 160 or 80
meter version...then design it for 40 meters and up! Just remember,
don't operate it on a lower frequency than it was designed for...tuner
damage may result! You can always tie the two ends together at the
tuner and use it as a random wire antenna with the tuner and it
may tune lower bands than it was designed for! Always check swr at low
power before attempting.
Remember when working with twinlead
(Flat TV feed type) don't use over about 100 watts of power to be safe.
For higher power, use the heavier, ladder, open or window
The Center insulator/strain
The two bare wires from each half
of the antenna are attached (soldered), one at a time to each side of the 2
conductor twinlead, ladder line, etc. (Meaning one side of antenna to one
conductor of feedline and the other side of the antenna to the other
conductor of the feedline.) Do not connect all together in the
Attach end insulators to both ends of
the antenna. Attach the insulators to their supports with UV
resistant rope, cord, etc and make sure you have enough to extend to the
outside support tie off points. As a further note for
those that are not experienced with wire antenna building, there are many
ways to build center and end insulators. Do a search on Google.com using
their "images" section for more ideas.
(Another option for
the center insulator/strain relief would be to take the feedline and wrap
it OVER a "dog bone" type (round), insulator and then back
down parallel with and touching the feedline making sure you
have a couple of inches left over for attachment of the bare
wires from the feedline to each half of the antenna. Then
use nylon ties to secure it tightly against the main feedline.
Use your tuner as per mfg's
There are many methods of "hanging" an antenna like this one
and various center supports can be used, like towers, metal pushup poles
(masts), etc. The use of a small cross arm made from heavy PVC or other
insulated material extending out a couple of feet or more from
the tower or metalic pole will help to prevent the feedline or radiating
parts of the antenna from touching any metal and shorting out. This also
helps to prevent the feedline from rubbing against anything in the
wind and eventually coming apart at that
When bringing the feedline down from the antenna to the
radio, always keep it away from sharp corners that can cut it due to
rubbing in the wind.
Remember to keep the feedline away from any metalic object by several inches.
Below is a very handy way of getting your feed line
into your radio room by going thru a window, metal wall,
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