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Old March 15th 04, 05:16 PM
Jerry
 
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"Mikey" wrote in message
...
Jeremy, is your RV skinned with fiberflas or sheet metal? Obviously,

you're
going to have more problems with sheet metal. Also, you said you had the
antenna installed. Maybe you need to go behind the installers, and beef

up
the grounding system?

Screwdrivers also give you a few more options. You can take the whole
antenna and mount it inside a PVC tube on the roof of the RV, and run it
horizontally. You can also run the motorized coil inside, and use it to
feed a separately-mounted whip (only a short distance away). In either
case, you still need to beef up the ground systems.

73,
Mike KI6PR
El Rancho R.F., CA



Yes, *IF* the body is fiberglass. If it is in close proximity to metal it
won't work well if at all! If your RF is metal, there isn't much you can do
except try to move it as far
away as possible from the body.

The other solution is to mount it on the rear ladder where it can be tilted
down for stowage while underway. It might
mean that you could only operate while parked in the RV
park. If the body is fiberglass, you could cut a block of
wood, paint it and cut a "V" in it, and tilt the antenna down to rest in
this "V". Then you could operate while
underway using one of those AMAC positioners--pricey
but would work.

Finally, I have seen screwdrivers mounted on the ladder
in the horizontal facing rearward and high enough to stay
away from other vehicles. Then it was braced with another piece of non
conductive material in that position
OR slanted up towards vertical. This, of course, kept it
out from bridges but let it operate well. Use a stiff upper
whip.

73

Jerry
K4KWH

"Jeremy Salch" wrote
Anyone ever setup a screwdriver on a RV and have it work very well ?

I have one installed but it preforms very poorly compared to
how well it worked on my car.

I think it is not working very well because the entire antenna is next

to
the side of the motorhome.. and on my car.. only maybe the bottom 2

feet
of it were beside another surface.

I guess another question would be.. does anyone know if it would

possibly
work better if it could be mounted at an angle instead of directly
vertical?


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Old March 15th 04, 06:20 PM
Cecil Moore
 
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Jerry wrote:
Finally, I have seen screwdrivers mounted on the ladder
in the horizontal facing rearward and high enough to stay
away from other vehicles. Then it was braced with another piece of non
conductive material in that position
OR slanted up towards vertical. This, of course, kept it
out from bridges but let it operate well. Use a stiff upper
whip.


Another idea is to locate the antenna on top of the vehicle and
install a very large top hat one foot above the coil. That would
limit the height of the antenna system to about four feet above
the top of the vehicle. I once tried an experiment of a 6'x14'
piece of 1/4" hardware screen mounted four feet above the cab
of my pickup used as a top hat for my High Sierra screwdriver.
It minimized the amount of coil required and put out one heck
of a signal. Field Strength measurements indicate that it would
have placed at the top in a 75m mobile shootout.

A 6'x14' top hat would actually be easier to implement on an RV
than on a pickup.
--
73, Cecil http://www.qsl.net/w5dxp



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Old March 15th 04, 07:44 PM
Jeremy Salch
 
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Cecil Moore wrote:

Jerry wrote:
Finally, I have seen screwdrivers mounted on the ladder
in the horizontal facing rearward and high enough to stay
away from other vehicles. Then it was braced with another piece of non
conductive material in that position
OR slanted up towards vertical. This, of course, kept it
out from bridges but let it operate well. Use a stiff upper
whip.


Another idea is to locate the antenna on top of the vehicle and
install a very large top hat one foot above the coil. That would
limit the height of the antenna system to about four feet above
the top of the vehicle. I once tried an experiment of a 6'x14'
piece of 1/4" hardware screen mounted four feet above the cab
of my pickup used as a top hat for my High Sierra screwdriver.
It minimized the amount of coil required and put out one heck
of a signal. Field Strength measurements indicate that it would
have placed at the top in a 75m mobile shootout.

A 6'x14' top hat would actually be easier to implement on an RV
than on a pickup.


I'm not sure i understand what you mean by a top-hat?
Do you thing something like this could be used with the body of the
scredriver antenna mounted horizontally on top of the rv and the Top hat
mounted close but seperately, making the antenna basically flush with the
top of the rv ? If that makes any sense.

--
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Old March 15th 04, 08:22 PM
Cecil Moore
 
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Jeremy Salch wrote:
I'm not sure i understand what you mean by a top-hat?
Do you thing something like this could be used with the body of the
scredriver antenna mounted horizontally on top of the rv and the Top hat
mounted close but seperately, making the antenna basically flush with the
top of the rv ? If that makes any sense.


It would look something like this with a four foot slanted bottom
section:

6'x14' hardward cloth top hat
+---screwdriver coil---+---================================
/ X X X
4' / X X non-conductive supports X
___/_____X______________________X_____________________ _____________X
Top of RV

The highest current would be flowing through the 4' slanted section
which is good. That four foot figure is arbitrary. Make it as tall
as is feasible. If it were me, and the top of the RV is 'z' ft. from
the ground, I would make the base as long as is legal, but that's
just me.

This is similar to a $20 junk box antenna with which I tied a 75m CA
shootout for top honors against top-of-the-line (expensive) bugcatcatchers
and screwdrivers. My loading coil and top hat were horizontal, as above.
My base was an 8 foot whip slanting from my trailer hitch up to an
elevation of about 12 feet above ground.
--
73, Cecil http://www.qsl.net/w5dxp



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Old March 15th 04, 07:42 PM
Jeremy Salch
 
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Jerry wrote:


"Mikey" wrote in message
...
Jeremy, is your RV skinned with fiberflas or sheet metal? Obviously,

you're
going to have more problems with sheet metal. Also, you said you had the
antenna installed. Maybe you need to go behind the installers, and beef

up
the grounding system?

Screwdrivers also give you a few more options. You can take the whole
antenna and mount it inside a PVC tube on the roof of the RV, and run it
horizontally. You can also run the motorized coil inside, and use it to
feed a separately-mounted whip (only a short distance away). In either
case, you still need to beef up the ground systems.

73,
Mike KI6PR
El Rancho R.F., CA



Yes, *IF* the body is fiberglass. If it is in close proximity to metal it
won't work well if at all! If your RF is metal, there isn't much you can
do except try to move it as far
away as possible from the body.

The other solution is to mount it on the rear ladder where it can be
tilted down for stowage while underway. It might
mean that you could only operate while parked in the RV
park. If the body is fiberglass, you could cut a block of
wood, paint it and cut a "V" in it, and tilt the antenna down to rest in
this "V". Then you could operate while
underway using one of those AMAC positioners--pricey
but would work.

Finally, I have seen screwdrivers mounted on the ladder
in the horizontal facing rearward and high enough to stay
away from other vehicles. Then it was braced with another piece of non
conductive material in that position
OR slanted up towards vertical. This, of course, kept it
out from bridges but let it operate well. Use a stiff upper
whip.

73

Jerry
K4KWH


That has been a thought.. fabricating some kind of mount to put on while
parked but take it down during travel. I'd like to keep it operational
during travel, but we'll see.

--
Registered Linux User #346565



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