End fed half wave ant.


From: Frank, G3YCC (frank@yorks.demon.co.uk)
Date: Sat Jul 22 1995 - 11:48:56 EDT

I apologise if this has been described before. It is an end fed half wave
wire for any band and may be of interest to QRPers in the field, or from
a mobile home. Being a half wave, no radials or counterpoise are needed.
   ________/----------------------------HALF WAVE WIRE-------
   | \
   = /<------ COAX TO RIG

The configuration at the left is a parallel tuned circuit, consisting of a
50pf cap across a slug tuned coil, wound to suit the band in use. Try 20-25
turns on 1/4 inch former for 14 mhz. The tap for the rig is about 4 turns up
from the 'earthy' end, the braid of the coax to the earthy end itself. Can
be built in a 35 mm film cassette, leave a hole to adjust ferrite core for
minimum SWR. You could mount 2 circuits in a container for two bands, say
14 and 21 mhz.
Works well, hope of interest to someone?
NOTE: If bothered with rf down the outer braid of the coax, try ferrite beads near
matching unit - not found necessary yet.

Frank G3YCC (G QRP 042)

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