[TenTec] The Rogers /Dobbins ARL Folded Conical Helix Antenna paper now published. Revolution in small HF Antenna design!

[Dr. Gerald N. Johnson, electrical engineer]

Tom, I agree.

And notice that all the NEC programs give antennas over ground 3 dB
excess gain. They do this by presuming that the isotropic reference is
located at coordinates 0,0,0 and half immersed in the ground plane, and
so only half the radiation from the isotropic reference shows above the
ground plane.

I have also found that the NEC family of programs give inconsistent
results for antenna elements that are not parallel to the coordinate
axes, especially with elements that do not intersect at right angles.

Remember the Crossed Field antenna? Claimed great field strength from a
small antenna pair (on the end of long open wire feed lines). Especially
when tested in the same backyard with the reference dipole.

Or the DDRR that was tested conveniently sitting on the ground plane of
the reference 1/4 wave vertical, which it shock excited. When tested as
a microwave model in an anechoic chamber neither the SWR, nor the
radiation efficiency were found.

73, Jerry, K0CQ
-- 
Entire content copyright Dr. Gerald N. Johnson. Reproduction by
permission only.