"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

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

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

"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


You may have to use the base coil to properly match this vertical. A 1/4
wave (with a reflected image - Marconi style) will have a 36 ohm impedance
at the feedpoint.
http://pages.intnet.mu/ingepru/antenna.htm

gb

w9gb wrote:
"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



You may have to use the base coil to properly match this vertical. A 1/4
wave (with a reflected image - Marconi style) will have a 36 ohm impedance
at the feedpoint.
http://pages.intnet.mu/ingepru/antenna.htm

gb


Thanks for the link. What tools would you recommend to check both
resonance and impedance with? MFJ seemed awful pricey.

Jonathan Laub wrote:
What tools would you recommend to check both
resonance and impedance with? MFJ seemed awful pricey.

If you think so, take a look at Tetronix and HP prices. :-)
--
73, Cecil http://www.qsl.net/w5dxp


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w9gb wrote:
"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



You may have to use the base coil to properly match this vertical. A 1/4
wave (with a reflected image - Marconi style) will have a 36 ohm impedance
at the feedpoint.
http://pages.intnet.mu/ingepru/antenna.htm

gb


Unexpected success. On the 16'5" leg of the antenna by dumb luck of
where I place the alligator jumpers found a 1.3 match on 40m! Though
this is not the freq where the antenna is supposed to be operated on it
does tell me that the coil is working. Once I get my hands on ant
analyzer I think it'll live.

"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.)

That may be half of your problem. #1, the PVC may be effecting the
overall length of the wire a bit. #2, if you have another vertical
wire right next to it, they will couple and all bets are off. You are
not tuning on 15 because with that extra 20m wire next to it, you are
now too long I bet.

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

Another comment...Ground mounting a 15 or 20 meter vertical is never
going to be that great a performer. You would be much better off with
something elevated off the ground. Of course, I realize this may not
be possible in your case.

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?

Right...
If it does, I'm over on
measurements for each. errr....

errrr....Yep, that, and the 20m wire, and you are probably way too
long...

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.

You should not need *anything* to match a 1/4 wave vertical. I know I
never have, on any band, or with any ground condition. If it doesn't
tune at least under 2:1 SWR, something is wrong... Like running two
verticals an inch apart...
You also shouldn't need any fancy analysers...I've never owned one
myself, and I don't have any trouble.

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.

You shouldn't need it. Just curious...If this is going to be a
portable antenna, what are you going to do about radials? Are you
going to add ground radials at each location? What a pain....
For a portable 15 m vertical, I would use something like a base fed
half wave.
Can be mounted anywhere, no radials are needed. Can be elevated, or
near the ground, although the higher the better. But, you can get what
you have to work, if you ditch the 20m wire that is next to the 15 in
the PVC. Or at the least, ditch it until you get the other band tuned.
In the real world, if you tried to make such a dual band antenna, it
would be best to tune 20 first, and then 15. But I don't really
recommend you doing that as it's a PIA to tune. I'm almost sure thats
most of the trouble you are having. The PVC could be effecting the
overall length also. MK

This is why I move the wires to the outside of the pvc. I have at least 2"
of separation between wires now. In addition to the ability to tune up on
40m w/o transmatch have noticed that generally speaking it tunes much easier
on each band when use the ant tuner. I bet the wires, when strung on the
inside, were crossing over or too close to each other. In any event, my
next step is to obtain an analyzer and move the alligator clips around on
the load coil. Once this beast is functioning, I am going to write up a
short how-to for the web site. This pvc actually looks okay in the
backyard.

-=Jon


"Mark Keith" wrote in message
om...
"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.)

That may be half of your problem. #1, the PVC may be effecting the
overall length of the wire a bit. #2, if you have another vertical
wire right next to it, they will couple and all bets are off. You are
not tuning on 15 because with that extra 20m wire next to it, you are
now too long I bet.

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

Another comment...Ground mounting a 15 or 20 meter vertical is never
going to be that great a performer. You would be much better off with
something elevated off the ground. Of course, I realize this may not
be possible in your case.

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?

Right...
If it does, I'm over on
measurements for each. errr....

errrr....Yep, that, and the 20m wire, and you are probably way too
long...

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.

You should not need *anything* to match a 1/4 wave vertical. I know I
never have, on any band, or with any ground condition. If it doesn't
tune at least under 2:1 SWR, something is wrong... Like running two
verticals an inch apart...
You also shouldn't need any fancy analysers...I've never owned one
myself, and I don't have any trouble.

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.

You shouldn't need it. Just curious...If this is going to be a
portable antenna, what are you going to do about radials? Are you
going to add ground radials at each location? What a pain....
For a portable 15 m vertical, I would use something like a base fed
half wave.
Can be mounted anywhere, no radials are needed. Can be elevated, or
near the ground, although the higher the better. But, you can get what
you have to work, if you ditch the 20m wire that is next to the 15 in
the PVC. Or at the least, ditch it until you get the other band tuned.
In the real world, if you tried to make such a dual band antenna, it
would be best to tune 20 first, and then 15. But I don't really
recommend you doing that as it's a PIA to tune. I'm almost sure thats
most of the trouble you are having. The PVC could be effecting the
overall length also. MK


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