[Antennas] HF Discone

[Cletus W Whitaker]

de WB2CPN South Central Pennsylvania   2002.06.27

An old USAF retiree speaks:  Back in the middle 50's when the USAF was
establishing a world-wide HF network to support our Cold War efforts
they installed "discone" antennas at the major locations to communicate
with aircraft.  (Rhombics and dipoles for everything else.)  These 
"discones" were constructed by placing three 70' wood poles approximately
50' feet apart in a triangle.  A guy wire was connected around the triangle
at the top of the poles.  At the center on the ground there was a 14" brass
cone which was connected to the coax and used as the discone apex.  There were
approximately 36 three-strand #12 antenna wires connected between insulators 
at the top wire and this brass cone.  (The cone had holes drilled in it to fit
the clamps.)  The coax shield was connected to a multi-wire buried counterpoise.
The wires were twice the radius of the triangle.  I suppose they were trying
to emulate a real discone where the disk is on the top and the cone is on
the bottom.  This upside down "discone" worked, but not as well as a resonant
vertical on a specific frequency.  I never saw anyone else try to do that...
                   73  Clete