Ladies and gentlemen, here is a perfect example of CB mentality that has
plagued the radio hobby from the beginning. Someone here obviously
doesn’t understand the fundamental nature of antennas but preaches bogus
information as it was gospel. Maybe the half wavelength mobile antenna
with the perfect match he refers to is his fiberglass loaded CB antenna,
which is advertised in half, full, one and a half, and every combination
of silly lengths to please CBrs as the dealers take their money. They do
match ok, but are not the full length, end fed, very high impedance half
wave antenna that he originally described in this thread. If you
actually read the ARRL handbook you will see Mr. Wolf’s grievous mistakes.
Bob


Zombie Wolf wrote:
Yes, I do have a 66 foot vertical, that is suspended from about an 80
foot tree out here, and i have been using it for a very long time. And
the mobil antenna is still on the old truck, also. Out here in the
country, they dont care what you put up for antennas. I also have a
horizontal loop antenna out there that is 150 feet on each side.

If you are so convinced that it doesnt work, then try it out. Its just
that simple. Put a three foot one up in the attic, as i described, and
see if it "fails to work".on the 155 mhz police band. Out here, we dont
use EZNEC. We just put 'em up, tune 'em, and use 'em. The antennas I
dexcribed here are well known to any novice operator (back when you had
to know something about it). The half - wave vertical is problably one
of the oldest antennas on the ham bands. It's not some "new idea" that i
dreamed up..........

"Dale Parfitt" wrote in message
news:caJOg.123$GO2.84@trnddc01...

"Zombie Wolf" wrote in message
...

"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.

So, you're telling me you have a 66' tall 40M vertical that is fed
directly with coax?
I would appreciate a model of the antenna in EZNEC or ELNEC or AO. In
addition, the reference and year of the Handbook or any professional
journal where it describes end feeding a half wave antenna directly
with coaxial cable.

Dale W4OP