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Old July 15th 03, 04:52 PM
Radio Amateur KC2HMZ
 
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On Tue, 15 Jul 2003 17:43:20 -0700, "denton"
wrote:

Ask any trucker about a co-phased cb antenna system....same principal
applies


My understanding of that setup is that the two cophased whips need to
be a quarter wavelength apart in order for it to work properly,
although I may have been misinformed.

However, if this is correct, it's gonna be tough to find a vehicle
that will let you separate two cophased whips by a quarter wavelength
at 80 meters - and driving it down most city streets would probably be
quite an experience even if you could find one that large. (Maybe the
tractor that moves the space shuttle from the vehicle assembly
building to the launch pad...top speed is slower than most folks can
walk, though)

73 DE John, KC2HMZ


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Old July 15th 03, 10:07 PM
Henry Kolesnik
 
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Default Mobile antenna balancing ?

I wonder if radiated energy would increase measureably if one were to try to
balance mobile whip antenna by having another whip connected directly to the
body and tuning it. If it would, how would one locate, size, and tune it?
tnx
hank wd5jfr


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Old July 15th 03, 10:44 PM
Richard Clark
 
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On Tue, 15 Jul 2003 16:07:15 -0500, "Henry Kolesnik"
wrote:

I wonder if radiated energy would increase measureably if one were to try to
balance mobile whip antenna by having another whip connected directly to the
body and tuning it. If it would, how would one locate, size, and tune it?
tnx
hank wd5jfr


Hi Hank,

The body is already the balancing whip you propose. Your addition
would be like adding a thin radial to an already massive one (like the
needle on a cactus).

Actually, what most Hams consider to be their antenna, it is actually
a tuned radial to the larger radiating frame. There is little
distinction between such primitive elements at large wavelengths if
you are talking about 80M or so. Some would argue that their
screwdriver elongates the current loop (the indicator of gain against
the overwhelming short dimensions) to qualify it as radiator, that is
simply a trick of symmetry and their being able to tune a thin element
instead of the more massive one (unless they drive a variable-stretch
limo).

73's
Richard Clark, KB7QHC
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Old July 16th 03, 01:43 AM
denton
 
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Ask any trucker about a co-phased cb antenna system....same principal
applies
"Henry Kolesnik" wrote in message
...
I wonder if radiated energy would increase measureably if one were to try

to
balance mobile whip antenna by having another whip connected directly to

the
body and tuning it. If it would, how would one locate, size, and tune

it?
tnx
hank wd5jfr




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Old July 16th 03, 03:07 AM
denton
 
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Ok I stand corrected.....
"TeeAye" wrote in message
...
On Tue, 15 Jul 2003 17:43:20 -0700, denton wrote:

Ask any trucker about a co-phased cb antenna system....same principal
applies


__________________________________________________ ______________

No, no, no. Different principle entirely. He's talking about using the
second whip connected directly to the body of the vehicle - in effect

using
it for the missing half of the dipole.

This has been done in the past by a number of folks and they seemed to

like
it. Whether it is worth the trouble is questionable. Give it a try and
let us know how it works out.

--
73, Bill W7TI





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Old July 16th 03, 04:44 AM
W5DXP
 
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denton wrote:
Ask any trucker about a co-phased cb antenna system....same principal
applies


It works on 11m pretty well when the two whips are low loss.
Not well at all on 75m.
--
73, Cecil http://www.qsl.net/w5dxp



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Old July 16th 03, 05:09 AM
Jerry Oxendine
 
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W5DXP wrote in message
...
denton wrote:
Ask any trucker about a co-phased cb antenna system....same principal
applies


It works on 11m pretty well when the two whips are low loss.
Not well at all on 75m.
--
73, Cecil http://www.qsl.net/w5dxp



Well, maybe yes and no. I think I heard that it is called "series tuning".
Now you would have to
mount the things on opposite ends of the car. Whether there is anything to
be gained, I haven't
tested it. It eliminates the matching network, tho. Heck, I've got enough
antennas on my car
without that.


Jerry
K4KWH



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Old July 16th 03, 05:17 AM
W5DXP
 
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Jerry Oxendine wrote:

W5DXP wrote in message
It works on 11m pretty well when the two whips are low loss.
Not well at all on 75m.


Well, maybe yes and no. I think I heard that it is called "series tuning".


I was thinking it was simply a resonant 1/4WL director or reflector
which would be very lossy on 75m.
--
73, Cecil http://www.qsl.net/w5dxp



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Old July 16th 03, 08:32 PM
W5DXP
 
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TeeAye wrote:
The original question was *not* about co-phasing. It was about using
another whip as a replacement for the missing half of a dipole. The second
whip would be connected directly to the car body and become an extension of
the body.


Assuming one whip is pointing up, which way is the other whip pointing?
--
73, Cecil http://www.qsl.net/w5dxp



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Old July 16th 03, 10:41 PM
Henry Kolesnik
 
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You tell me, that's part of the question.
tnx
hank wd5jfr
"W5DXP" wrote in message
...
TeeAye wrote:
The original question was *not* about co-phasing. It was about using
another whip as a replacement for the missing half of a dipole. The

second
whip would be connected directly to the car body and become an extension

of
the body.


Assuming one whip is pointing up, which way is the other whip pointing?
--
73, Cecil http://www.qsl.net/w5dxp



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