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echo: ham_tech
to: JEFF EDMONSON
from: FRED MCKENZIE
date: 1997-07-12 12:23:00
subject: J-Pole Antenna

In a message dated 07-08-97 JEFF EDMONSON wrote to ROB DENNIS:
 JE> A 'tassle' is just a chunk of wire around 4 to 6" in length, soldered
 JE> onto the existing dipole, at the distance from the feedpoint
 JE> calculated for 40m, to allow for resonation at 40m.
 JE> The result is a dual-band HF antenna that will not only work on
 JE> 75/80, but 40/15m as well.  (15m being the third harmonic of 7MHz)
  Jeff-
     Are you saying this scheme WILL work?  If so, I can't argue with 
uccess,
 even though it doesn't appear likely!
     I would think that current on both sides of the Tassle would have to be
near-zero, for a voltage maximum to exist.  The remaining quarter wave length
is still part of the antenna, so current at the far end would have to be 
igh.
  Since you can't have current flowing from the end of the antenna wire, it
CAN'T be a current maximum, and must be a voltage maximum (or at least a
relatively high voltage).
     This forces current high/voltage low at location of the tassle, and
current low/voltage high at the feedpoint.  Such an antenna may be resonant,
but I would expect feedpoint impedance to be quite high.
     If you want to operate with a single, simple antenna, why not use this
similar configuration:  A dipole as long as you can fit on your property, fed
with open-wire line, matched by a tuner with balanced output.  SWR is high on
most bands, but feedline loss is low on HF.  There may be some loss in the
tuner, but the transceiver sees 1:1 SWR.
     73, Fred, K4DII
 -> Alice4Mac 2.4.4 E QWK Eval:30Sep95 
Origin: Alice strikes back @
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