Is it a CB or VHF marine antenna?

Scott Downey

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Feb 23, 2004, 10:16:47 AM2/23/04

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I have a white fiberglass top loaded antenna that is 48 inches long.

At the bottom of the antenna where the metal part screws onto the L bracket
aluminum mounting base is imprinted 'wondershaft'.

It is toploaded because the top 15 inches is thicker and I assume there is a
coil of wire under the white fiberglass covering.
It uses a Pl259 coax connector mount on the base for the coax cable.

Does anyone know if this is a marine CB antenna or would it be a marine VHF
antenna or how to tell the difference?
Thanks for any info.

David G. Nagel

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Feb 23, 2004, 11:03:56 AM2/23/04

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Scott;

What you have there is a CB antenna. You can tell from the loading coil
at the top of the stick. A VHF marine antenna will not have any coils as
the 48" length is sufficent for a half wave vertical dipole.

Dave WD9BDZ

Scott Downey

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Feb 23, 2004, 11:14:12 AM2/23/04

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Thank you.
I was hoping toward CB. I am going to add a CB radio to my boat. I already
have a VHF radio.

I have a SWR meter. Will the length of the coax have an effect on the
tuning? I would like to have a run from the top of the flybridge to cabin of
perhaps around 20 feet.

"David G. Nagel" <na...@core.com> wrote in message
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Cecil Moore

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Feb 23, 2004, 11:27:00 AM2/23/04

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Scott Downey wrote:
> I have a SWR meter. Will the length of the coax have an effect on the
> tuning? I would like to have a run from the top of the flybridge to cabin of
> perhaps around 20 feet.

Is the (metal?) flybridge your ground plane?
--
73, Cecil http://www.qsl.net/w5dxp

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Scott Downey

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Feb 23, 2004, 12:29:53 PM2/23/04

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The boat is mostly wood and fiberglass, only metal is railings.

"Cecil Moore" <Cecil....@ieee.ONEDOT.org> wrote in message
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Scott Downey

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Feb 23, 2004, 12:35:12 PM2/23/04

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There is a large stainless metal ground plate with molded in tubes (
increased surface area) attached to the keel.
About 4 feet by 2 feet. I was told years ago these plates may have been used
for AM ground plates??? when using an AM transmitter or perhaps for
lightening protection. The boat was built in 1970. All the electronics are
grounded and this is also included in the ground.

"Cecil Moore" <Cecil....@ieee.ONEDOT.org> wrote in message
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Cecil Moore

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Feb 23, 2004, 1:08:42 PM2/23/04

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Scott Downey wrote:
> The boat is mostly wood and fiberglass, only metal is railings.

To what is the coax shield going to be tied? If that antenna is
an electrical 1/4 wavelength, where's the ground plane?

WB2JKX

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Feb 23, 2004, 2:17:03 PM2/23/04

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Scott Downey <sdown...@msn.com> wrote in message
news:c1ddks$1gqa9p$1...@ID-150959.news.uni-berlin.de...

> There is a large stainless metal ground plate with molded in tubes (
> increased surface area) attached to the keel.
> About 4 feet by 2 feet. I was told years ago these plates may have been
used
> for AM ground plates??? when using an AM transmitter or perhaps for
> lightening protection. The boat was built in 1970. All the electronics
are
> grounded and this is also included in the ground.
>
>

Probably would work O.K. for the 2-3 Mhz HF marine band and a mast supported
antenna wire, but you'll need a "local" groundplane for the 27Mhz antenna to
attach the coax shield to, as was previously questioned.

Scott Downey

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Feb 23, 2004, 3:35:24 PM2/23/04

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Are you saying it wont work?
Why would the manufacturer make a marine CB antenna knowing it would be put
on a fiberglass boat knowing that most people would simply hook up the coax
and see it it works.
I read in the marine catalogs about marine CB antennas designed for boats
and not to be concerned about a ground plane.
Anyone know the answer?

"Cecil Moore" <Cecil....@ieee.ONEDOT.org> wrote in message

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Scott Downey

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Feb 23, 2004, 3:54:11 PM2/23/04

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I found this

"I agree with the other posts. The length of cable is not an issue and your
problem is a lack of a good groundplane. I suggest that you try a CB marine
antenna. These antennas are design to operator without a groundplane.
However, they are probably not design to handle high power. Looking at
shakespears webpage it looks like there antennas are limited to 25 watts
max. Well with in the range of a legal CB radio."

http://www.shakespeare-marine.com/index.html

what a long link

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=voxL7.18%24ib5.12973%40news2.news.adelphia.net&rnum=4&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26q%3Dmarine%2Bcb%2Bantenna%2Bdesign%26sa%3DN%26tab%3Dwg

"Scott Downey" <sdown...@msn.com> wrote in message

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Richard Clark

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Feb 23, 2004, 3:58:43 PM2/23/04

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On Mon, 23 Feb 2004 15:35:24 -0500, "Scott Downey"
<sdown...@msn.com> wrote:
>I read in the marine catalogs about marine CB antennas designed for boats
>and not to be concerned about a ground plane.
>Anyone know the answer?

Hi Scott,

It could be a half-wave antenna (or jimmied to look like one) and it
counts on the cable feed to act as the minimal counterpoise to work
against.

OR

It could be outright baloney about not needing a ground plane.
CB does not have the reputation for marketing to the savvy.

73's
Richard Clark, KB7QHC

Cecil Moore

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Feb 23, 2004, 5:46:48 PM2/23/04

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Scott Downey wrote:

> Are you saying it wont work?
> Why would the manufacturer make a marine CB antenna knowing it would be put
> on a fiberglass boat knowing that most people would simply hook up the coax
> and see it it works.
> I read in the marine catalogs about marine CB antennas designed for boats
> and not to be concerned about a ground plane.
> Anyone know the answer?

I said "if it is a 1/4WL antenna..." If it is a 1/2WL antenna, it will work
without a ground plane. Does it have a coax connector on it? If so, what is
the outside of the connector tied to?

Scott Downey

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Feb 23, 2004, 8:42:11 PM2/23/04

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Yes, it has a pl 259 coax connector on the antenna and it did not come with
any cable.

"Cecil Moore" <Cecil....@ieee.ONEDOT.org> wrote in message

news:403a8...@corp.newsgroups.com...

Cecil Moore

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Feb 23, 2004, 9:24:35 PM2/23/04

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Scott Downey wrote:
> Yes, it has a pl 259 coax connector on the antenna and it did not come with
> any cable.

But what is the outside shield of the pl259 connected to inside the antenna?

CW

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Feb 24, 2004, 2:46:45 AM2/24/04

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Cecil is not fallowing along. I have an antenna just like yours and it is
designed to work without a ground plane. It is designed for boats.

"Scott Downey" <sdown...@msn.com> wrote in message
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Scott Downey

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Feb 24, 2004, 10:11:15 AM2/24/04

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Sounds right to me, thanks.
How well does this antenna work for you?
I have not installed the radio yet.

"CW" <clinton...@comcast.net> wrote in message
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-Rev Jones

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Feb 24, 2004, 1:27:14 PM2/24/04

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They work I have even seen apt window antennas but range is awful.
The best thing I found is mount with 2 U bolts or s steel hose clamps to the
stern railing as close to the centerline as possible (most those antennas
have a brass plated sleeve at the base). It's a sailboat when the gate s
closed you have plenty of ground plain.
Very difficult to get an acceptable polar pattern on Boats.
If you have a large boat use a 2 co-phased classic Shakespeare "Super Big
Stick" (21 ft sleeve antenna) a-side and above the pilot house is the
ultimate
2 co-phased antennas on the rear port and starboard stern rails work good
also.

If you can afford a boat dont be cheap with "Rube" rigged antenna systems,
it can mean a life or death situation

"Scott Downey" <sdown...@msn.com> wrote in message
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CW

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Feb 24, 2004, 3:16:57 PM2/24/04

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Don't know, never tried it. Bought it for a specific application about ten
years ago. A change of plans made it unnecessary.

"Scott Downey" <sdown...@msn.com> wrote in message

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Scott Downey

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Feb 24, 2004, 4:29:23 PM2/24/04

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I am not too concerned, I have VHF primarily and am just interested in
adding CB to the boat for fun. I have a handheld GE CB that is for fun and
will be used to talk to the main CB in the boat.

We do use a cell phone, I called the CG on it when I was in a storm and hit
a pier which destroyed my VHF antenna.

"-Rev Jones" <rpj...@GETOUTverizon.net> wrote in message
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greg z

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Feb 26, 2004, 6:33:49 PM2/26/04

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>We do use a cell phone, I called the CG on it when I was in a storm and hit
>a pier which destroyed my VHF antenna.

---------------------------------
A roll up J-pole and a fishin pole come in very handy in this situation.
KC*VIF
Greg Z
to thine own sound be true