J pole
 

Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.

Richard wrote:
Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


A search on google found this marine J-pole.

http://www.arrowantennas.com/j-pole.html

Looks well put together, and covers what you want at 1.5 to 1 claimed.

tom
K0TAR

Receive only antenna shouldn't be nearly as critical as x-mit. fat tubing
(say 1/2" copper water tubing) will be wider band than say 1/8"
brazing/brass wire.

A search for 2 meter J-pole or VHF J-pole will turn up a lot of amateur/ham
antenna designs, just shorten the lengths to 146 MHz / 159 MHz (0.92) times
the published lengths.

You also can make a 1/4 wave ground plane antenna w/ a SO-259 (UHF)
connector (or other flange mount RF connector) and a 17 1/2" (about) piece
of brazing wire or small tubing vertical in the center lead solder socket
and 3 or more (4 is easest) 17 1/2" wires attached to the coax shield
grounded mounting flange and bent downward 45° or so. Google for home made
ground plane antenna (and/or 1/4 wave, 2 meter, VHF, etc.) again scale 2m
dimensions by 0.92

Performance for either should be similar, again the fatter the element
diameter the broader the bandwidth, but for receive it is less critical than
for transmit.


"Tom Ring" wrote in message
...
Richard wrote:
Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole.
I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to
cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


A search on google found this marine J-pole.

http://www.arrowantennas.com/j-pole.html

Looks well put together, and covers what you want at 1.5 to 1 claimed.

tom
K0TAR

"Richard" wrote in message
...
Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to
cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


http://www.hamuniverse.com/jpole.html This is the directions for the J-Pole
of copper pipe that I use very successfully for 2-way marine band traffic.
It is centered on 156.800 and works great over the whole marine band. I do
not use any form of choke on it, and feed it with RG-8U through a I.C.E
Lightning Arrestor from a JRC marine transceiver. Ground it well.

Jack Painter
Virginia Beach, Va

"Jack Painter" wrote in message
news:D%Ouc.720$Y21.452@lakeread02...
"Richard" wrote in message
...
Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole.
I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to
cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


http://www.hamuniverse.com/jpole.html This is the directions for the
J-Pole
of copper pipe that I use very successfully for 2-way marine band traffic.
It is centered on 156.800 and works great over the whole marine band. I do
not use any form of choke on it, and feed it with RG-8U through a I.C.E
Lightning Arrestor from a JRC marine transceiver. Ground it well.

Jack Painter
Virginia Beach, Va

Obviously works then. No mention of the bandwidth of these designs.

That Arrow antenna is a snap to build and even though centered
on 2m band receives really well fm aircraft band to wx band.

Richard WB8KRN


"Tom Ring" wrote in message ...
Richard wrote:
Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


A search on google found this marine J-pole.

http://www.arrowantennas.com/j-pole.html

Looks well put together, and covers what you want at 1.5 to 1 claimed.

tom
K0TAR

It looks enough better mechanically than the normal J, that I decided I
have to build one just to see if it works well. And I don't need one,
but that probably hasn't stopped too many people in this group.

tom
K0TAR

Richard Heindel wrote:
That Arrow antenna is a snap to build and even though centered
on 2m band receives really well fm aircraft band to wx band.

Richard WB8KRN


"Tom Ring" wrote in message ...

Richard wrote:

Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.


A search on google found this marine J-pole.

http://www.arrowantennas.com/j-pole.html

Looks well put together, and covers what you want at 1.5 to 1 claimed.

tom
K0TAR

I have a assortment of antenna that I can use for listening .The one
that I get the best Reception on is a 5/8 wave groundplane, feed with
RG-59. I put my MFJ antena analszer on it and and the SWR was nearly
flat all the way across (123 Mhz to 172 Mhz) this year I have things
set up o I can hook two scanners on to the one antena. One thing I
would advise, If you are gonig to cooper in your construction, give it
a coat of trimcald. I ended up doing some high level repairs to my
antena . The groundplane element had a a greenish ttimg to them after
on one year of being exposed to the elemts(weather).

On Mon, 31 May 2004 22:05:17 +0100, "Richard"
wrote:

Whenever I think about a simple VHF wideband omnidirectional vertical
antenna for my marine band listening, I'm always thinking folded dipole. I
think I've got folded dipole on the brain. But wait - isn't it better to
make J-pole. Constructionaly simpler I think, and you can feed with
unbalanced coax. Are J-poles wideband antennas? I want any antenna to cover
156-162 MHZ (6Mhz bandwidth) - RECEICE ONLY. Would a J-Pole do here,
bandwidth-wise?TIA.

I have a assortment of antenna that I can use for listening .The one
that I get the best Reception on is a 5/8 wave groundplane, feed with
RG-59. I put my MFJ antena analszer on it and and the SWR was nearly
flat all the way across (123 Mhz to 172 Mhz) this year I have things

If you have an antenna with a swr that is flat over that large of a
frequency range , you are loosing much of signal in the coax. You can
probably take off the antenna and have about the same swr. If that is your
best antenna, you have much work to do on all your antennas.

"Ralph Mowery" wrote in message
...
I have a assortment of antenna that I can use for listening .The one
that I get the best Reception on is a 5/8 wave groundplane, feed with
RG-59. I put my MFJ antena analszer on it and and the SWR was nearly
flat all the way across (123 Mhz to 172 Mhz) this year I have things

If you have an antenna with a swr that is flat over that large of a
frequency range , you are loosing much of signal in the coax. You can
probably take off the antenna and have about the same swr. If that is
your
best antenna, you have much work to do on all your antennas.

Ralph, that was a pretty funny way of saying that RG-59 is suitable for 3'
test leads only, never for transmission or receiving ;- 0 The
differences realizable with RG-8U or 9913 would be amazing. For anything as
high as high as 225-400mhz, hobbyists split hairs over a 1/2 db, and can
never tolerate a 75ohm dummy load as a feedline. Down around 123 mhz, there
would be slightly less difference. But a coat hanger fed with 9913 might do
as well as a Yagi with RG-59! In order to operate during inclement weather,
I had to add the losses from two connectors (with lightning arrestor) I
didn't have when I used to disconnect and short to the ground bus. That had
a noteable effect on vhf and uhf dx-reception. I have not tested dx-transmit
since that installation.

Jack Painter
Virginia Beach, Va