A simple antenna is resonant at one fundamental frequency.
Get your hands on one of the new cheap antenna analyzers and find that
frequency.
Improve your counterpoise and adjust the radiator's length to make your wire
resonant where you want it to be resonant
("resonant" = a purely resistive load).
Then match the antenna's impedance (surely 50 ohms for any 1/4 wave
vertical) to your line with a tuner or transformer.
BTW tuners suck.
Power.
73
H., NQ5H

PS
I like my BiggIR on 15 as a 3/4 lambda "singer".

"J. Laub" wrote in message
...
I'd like to construct a 15m vert that does not require use of my MFJ
Versa Tuner II. Portability. I started over this afternoon on a new
vertical using plans from a web site.

WIRING:
I've suspended an 11'1" #12 wire for 15 inside some pvc. (While I was
at it I also suspended a 16'5" #12 wire inside the same piping for 20m.)

RADIALS:
I've got six underground radials, 2 @ 11' and 4 @ 5-1/2"

FEEDER & CONNECT POINT:
Using 52ohm RG58 (the thin stuff) to feed into a female coax chassis
mount at base of system. I have a small (maybe 4") of line from the
center of the chassis mount leading to the connection point bolt/wing
nut for each/either wire. This wire is 4" and I suspect this 4" may
cause some electrical lengthening right? If it does, I'm over on
measurements for each. errr....

Other than this possible lengthening, I cannot think of what else to do.

In short, I should probably borrow a dip meter and check for impedance
problem? I was reading that I should attach a silver mica capacitor
across the wires. Haven't tried this yet as they are still in the mail.

I was thinking ahead too when I put this stinker up. I've got a 22-turn
base coil sitting there as my next try but that sort of defeats my
original simplicity plan.

73's-

-=Jon



w9gb wrote:

"J. Laub" wrote in message
...

I've constructed a 1/4-wave 15m vertical from 11' of 3/4" copper tubing
(water type). It's being fed with coax.

Much to my frustration, I am unable to get this thing to resonate w/o
the
use of a transmatch. Any tips, ideas or good plans?

73's

-=Jon


Jon -

One of the old ARRL Antenna Handbooks (Green cover - circa 1973) had a
15
meter dipole constructed form 2 piece of 1/2 inch 10' electrical conduit
and
a small coil wound from 1/8" copper or brass tubing (50 ohm coax fed).

The impedance for a vertical will be quite low (less than 50 ohms) what
are
you using for matching?

15 meters / 4 = 3.75 meters (1/4 wave) ~ 12.3 Feet

Greg
w9gb