"Dale Parfitt" wrote in message
news:rMHOg.91$W13.22@trnddc05...

"Zombie Wolf" wrote in message
...
Make a Half - wave vertical with pipe. If the wall is dry wood, you can
simply clamp it in place on the wall. You figure out the length of this
antenna by the following formula

468 / freq (in MHZ)

Hook the center conductor of the coax to the antenna, and then simply run
a wire from the shield braid of the coax to a nearby ground. Presto. You
now have a half - wave vertical.

The end impedance of a half wave antenna is in the neighborhood of
1000--5000 Ohms depending on the diameter of the conductor; fatter
conductors, lower Z
The END impedance is not where you are making your connection. The impedance
at the connection point on a half wave vertical is about 30 to 35 ohms. Not
a perfect match , but certainly not 500 to 1 !.

Connecting a coaxial cable to the bottom end of a half wave element and
the shield to ground will then result in a V.S.W.R. of roughly 2500/50 or
500:1. You need to convert the feed Z to 5o Ohms either by:

They didnt "convert" it when i ran a half wave whip on my car , and the
shield was grounded to the chassis. I ran this for 15 years and never had an
swr of over 1.5. My 40 meter vertical outside doesnt have an swr of 500,
either, and it has worked well over the last 20 years. No stub matching is
required in either case. Better tell this to the thousands of hams that have
been running these antennas for the last 50 years ! No antenna matcher is
needed, either (your lumped L or pi network). The formulas and the antenna
itself came right out of the arrl handbook.

1. A quarter wave stub as in the popular J antenna
2. A lumped element L or Pi network


Dale W4OP