Bull****. It is NOT a bazooka, it is a simple ground plane with bent over
rods.

STOP TRYING TO CONFUSE THE GUY. It is a simple ground plane with removable
radials. STOP POSTING ABOUT THE STUPID BAZOOKA.

Jim




"Bryan" wrote in message
...
Chuck James wrote:
This looks like what i am asking for, but the picture is not very clear.
Any more details anywhere?

Hi Chuck,

I found the image he
http://www.alpharubicon.com/elect/vertdipoleniet.htm
and cleaned it up -- not much more info available on that page. It's
basically a dipole turned vertical. With the feedline going thru the
bottom
half and connecting at the top of that section, it becomes a "bazooka"
vertical.

Jesus Christ, I give you step by step directions with part numbers and parts
sources and you can't figure out how to do it.

Go away. Just go away.

Jim




"Chuck James" wrote in message
. net...
This looks like what i am asking for, but the picture is not very clear.
Any more details anywhere?

I'm sure you know what you want, and I'm sure you have all the lab equipment
necessary to calculate VSWR on an antenna inside a conductive structure.
I'm also sure you have built antennas for emergency and portable use for
fifty years, so you are on your own so far as I'm concerned.

Cheap, easy, small. Pick two.

Best of luck; write if you get work.

Jim



"Chuck James" wrote in message
. net...
Thanks. I appreciate the suggestion, but I have built the antenna you
described, using welding rod, plus a 440 MHz (smaller version), but in a
crowded room the radials stick out farther than I want. I tried building
a TV antenna line J-Pole today, but the SWR was higher than I expected. I
haven't tried shortening it yet, but will when I get time. But I would
still have to find some way to hang it from the ceiling or something. I
really want something small, unobtrusive and cheap and easy to
build.standing and as small as practical. The Welding Rod antennas
made with 45
degree radials are a little bulky to move through congested hallways.
The idea is to make it portable enough to move from room to room as
needed. Long radials would impede moving through hallways.
Thanks in advance, KE5GEO

RST Engineering wrote:
...

For years now I have had an alarm on the wall of the shack; its' meter
needle has never moved.

I built it for an old-old magazine article issued on April 1 of some
past year, written by a Dr. Kuku I believe.

I surely thought I must have made an error in its' construction, as,
like I say, the meter needle has NEVER moved.

But, darn it, when I opened up your post--the damn meter needle went
clear off scale!

Darn ku-ku meter works!!!

JS

Jim exclaimed:
Bull----. It is NOT a bazooka, it is a simple ground plane with bent over
rods.

STOP TRYING TO CONFUSE THE GUY. It is a simple ground plane with
removable
radials. STOP POSTING ABOUT THE STUPID BAZOOKA.

Jim

Jim:

Alright, it's not a bazooka; it's a decoupling sleeve (thank you for the
enlightenment). Semantics aside, it will do what the OP wishes it to, and
in a physical representation that will work within his constraints.

Regards,
Bryan

Jim demanded:
STOP POSTING ABOUT...
Jim

Jim:

AFIK, usenet is open to anyone to post anything that does not transcend
legal limits, and I have not come anywhere close to that limit. Until I
cross that line, you (or anyone) is welcome to challenge anything I may post
in a *non-confrontational* manner.

Regards,
Bryan WA7PRC

"Cecil Moore" wrote in message
t...
John Smith I wrote:
Cecil Moore wrote:
RST Engineering wrote:
(By the way, you are operating close enough to the third harmonic of
144 on 440 that the antenna will perform quite well on both
frequencies.)

It will even perform well as a satellite antenna on
440. EZNEC says it has a TOA of about 45 degrees.

Hmmm. In some cases, would be nice to keep more of that signal
terrestrial.

That's the subtle point I was trying to make. To keep
the TOA low, the antenna should not exceed 5/8 WL.
6/8 WL raises the TOA. That's not optimum for hitting
repeaters unless they are on very high, very close
mountains.
--
73, Cecil http://www.w5dxp.com

Yup, the peak of the main lobe is elevated. ... but my 144 copper pipe
j-pole does put sufficient 440 energy toward the horizon that I am often
able to hit a repeater more than 70 miles away (Santiago Peak in Orange
County CA from southern San Diego County). Power out is around 4 watts from
a Yaesu FT-530.

Just now I tried Santiago and didn't hear back, so I tried 449.08 on Palomar
Mountain, 45 miles away, with a half watt and bought it up. Antenna is only
20 ft above ground; house is around 510 ft above sea level on a small rise.

"Chuck James" wrote in message
t...
I know I could just go buy a mag-mount mobile antenna, but would it be
possible or even practical to build a J-pole type or vertical (without long
radials) antenna for 2m/70cm, out of welding rod, which could be small
enough to be easily portable and used inside different rooms? Our local
RACES is trying to set up a volunteer communications network inside several
different city and county offices to assist in emergencies. I have
searched (a little) for such a design, and found something similar, made
out of TV line, but would prefer something that could be made free standing
and as small as practical. The Welding Rod antennas made with 45 degree
radials are a little bulky to move through congested hallways. The idea is
to make it portable enough to move from room to room as needed. Long
radials would impede moving through hallways.
Thanks in advance, KE5GEO



Yes you should be able to build one out of welding rod. I built mine out of
brazing rod and an N connector. It is an open stub design where the bottom
end of the matching section is open instead of shorted like most designs and
is fed from the bottom. 3/4 wl part is connected directly to the center pin
of an N connecter, short side is connected to the outside of the N
connector. Seems to work OK but it got to be a real pain and probably a
saftey hazard "put your eye out kid". Finally made an in-door antenna
modeled after a 60s 70s style pole lamp. SImplest version was a piece of PVC
pipe about 8 ft long that you wedge between ceiling anf floor and tape a
dipole to the antenna. I think I still have a wooden one around somewhere
that uses pieces of a tape measure for elements..

Sal M. Onella wrote:
Yup, the peak of the main lobe is elevated. ... but my 144 copper pipe
j-pole does put sufficient 440 energy toward the horizon that I am often
able to hit a repeater more than 70 miles away (Santiago Peak in Orange
County CA from southern San Diego County).

Yep, paraphrasing Roy:
All antennas emit energy at all angles.

I just don't like to waste 10m/VHF/UHF energy
at high angles.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
...
I just don't like to waste 10m/VHF/UHF energy
at high angles.

Cecil:

And, neither do I. (well, 11m band--sometimes. Just for medicinal
purposes, mind you. evil grin)

I have pursued the "Ultimate 10M Antenna", and a yaga or quad is/are
great. However, I like a omni to listen for traffic on. And, when
there are high winds, I like to point those directional antennas into
the wind. (have stripped too many rotor gears and suffered too much
damage in past decades)

Like you point out, and I concur, the perfect Omni which throws no rf to
the sky is elusive ... strange too, we can do it with light.

I have gotten used to the "RF GODS" extracting their portion of my rf
field to their realms in the sky (sometimes they toss a bit back to
australia though, I like the women there )

Regards,
JS