[Elecraft] Stealth Antennas

[Stuart Rohre]

Dipole refers to the antenna having the length to have all of a half wave
current distribution contained on its length.  Doublet is a more general
description of a center fed antenna.  It can be a Double Zepp 5/8 wave on
each leg; one wave on each leg, or untuned to any one band of use; but
parallel tuned line fed by a tuner for all band use.

Back to the piece in QST, attic antennas can work well.   I have had 20 to
10 on common feed with fanned out dipole arms since 1975.   Worked around
the world with them.   They were made of 20 gauge or so enameled wire, with
plastic picnic pak knives as insulators.  Tied off ends of insulators with
fishing line to truss supports.

Cutting the dipoles by traditional 468 over F formula for half wave dipoles
left the 20 m one resonating about 13 Mhz, not mid 20m band!   Thus, the
wiring in attic, and metal air conditioning ducts were detuning the dipoles
above them along the roof ridge pole.   The roof surface is asphalt shingle
on no known metal content.  Trusses are wood with metal gusset plates.
Probably all metal pieces contribute to the total tuning.  The dipoles were
tied together at a center balun/insulator and RG 58 used to the shack, a run
of about 15 feet.

72,
Stuart
K5KVH