I am thinking of getting a Twin Trucker for my Ford Explorer...

I would mount the antennas to the roof rack and run a ground wire since the
racks have a rubber gasket to prevent leaks. I also want to use springs at the
base in case I get some low branches etc.

Will the springs hinder the quality of the signal? If so, is it marginal?
Is the ground wire idea ok?

Rinning a Cobra CB.

"PES949" wrote in message
...
I am thinking of getting a Twin Trucker for my Ford Explorer...

I would mount the antennas to the roof rack and run a ground wire since
the
racks have a rubber gasket to prevent leaks. I also want to use springs at
the
base in case I get some low branches etc.

The rack isn't the best place to mount them, the ground is marginal at best.
Can you get 9' separation, or close to it, on the explorer?
Co-Phased antennas need to be run at 1/4 wave separation, to get the
front-back pattern they are designed to deliver. When you deviate from that,
the pattern turns to slop.

Springs won't affect it much, just reduce the antenna length to compensate.

I know what you mean about height.. On my current rig, the front antenna is
a $150 Diamond Super-gainer that tops out around 10' off the road. That one
is too heavy for any single mag mount, and if you did, when it falls over,
it will break the coils. It dosen't bend either.. It just rips the roof out
if you hit something.

The Cobra 6000 is on a mag mount in the back center, which is working fine.
On the Explorer, I mounted it through the roof, near the back, with a
large-footprint bulkhead mount to spread the stress. There is room, up under
the header back there, to accomodate the connector and such.

The roof metal is better on the explorer though, than my current rig.
Here's what I had to do, to mount a ham antenna that's probably lighter than
what you're considering, on the Expedition.
http://www.inchase.org/outflow/event...2/f5Mount.html

On Fri, 2 Jan 2004 14:39:53 -0500, "Dave VanHorn"
wrote:


"PES949" wrote in message
...
I am thinking of getting a Twin Trucker for my Ford Explorer...

I would mount the antennas to the roof rack and run a ground wire since
the
racks have a rubber gasket to prevent leaks. I also want to use springs at
the
base in case I get some low branches etc.

You should be able to remove the head liner and find the bolts that
mount the roof mount through the roof. Run a section of braid between
the bolt and the body, try to keep it as short as you can.


The rack isn't the best place to mount them, the ground is marginal at best.
Can you get 9' separation, or close to it, on the explorer?
Co-Phased antennas need to be run at 1/4 wave separation, to get the
front-back pattern they are designed to deliver. When you deviate from that,
the pattern turns to slop.


That isn't true Dave, Twin Truckers are fed in phase. There isn't any
front to back ratio. When mounted 1/4 wave apart on a vehicle,
perpendicular to the axis of the vehicle, the pattern is more oval
shaped inline with the vehicle. If you decrease the spacing the
pattern becomes more circular or less directional. There is nothing
wrong with that, but you could obtain the same pattern with a single
antenna. But it wouldn't look as nice as 2 antennas swaying back and
forth.

Springs won't affect it much, just reduce the antenna length to compensate.

I know what you mean about height.. On my current rig, the front antenna is
a $150 Diamond Super-gainer that tops out around 10' off the road. That one
is too heavy for any single mag mount, and if you did, when it falls over,
it will break the coils. It dosen't bend either.. It just rips the roof out
if you hit something.

The Cobra 6000 is on a mag mount in the back center, which is working fine.
On the Explorer, I mounted it through the roof, near the back, with a
large-footprint bulkhead mount to spread the stress. There is room, up under
the header back there, to accomodate the connector and such.

The roof metal is better on the explorer though, than my current rig.
Here's what I had to do, to mount a ham antenna that's probably lighter than
what you're considering, on the Expedition.
http://www.inchase.org/outflow/event...2/f5Mount.html

(PES949) wrote:
I am thinking of getting a Twin Trucker for my Ford Explorer...

I would mount the antennas to the roof rack and run a ground wire since
the racks have a rubber gasket to prevent leaks. I also want to use
springs at the base in case I get some low branches etc.

Will the springs hinder the quality of the signal? If so, is it marginal?
Is the ground wire idea ok?

Rinning a Cobra CB.

The spring becomes part of your wavelength, no big deal. I'm not sure
that you'll gain anything with the twins, except if you're in Texas and
also add some bull horns to your hood. Then the gun rack looks better.

I'd put a single Wilson roof mount, right in the middle if I were
you. ( not the magnet, although they work well too) ymmv

That isn't true Dave, Twin Truckers are fed in phase. There isn't any
front to back ratio. When mounted 1/4 wave apart on a vehicle,
perpendicular to the axis of the vehicle, the pattern is more oval
shaped inline with the vehicle.

That's what I was referring to, but I was in a rush, and wasn't clear.
The intended app is to concentrate power along the (presumably straight)
road, in front, and in back of you. As you depart from 1/4 wave spacing,
that deteriorates.

If you decrease the spacing the
pattern becomes more circular or less directional. There is nothing
wrong with that, but you could obtain the same pattern with a single
antenna. But it wouldn't look as nice as 2 antennas swaying back and
forth.

It gets pretty spiky as well, which sucks.

When u co-phase antennas you split the power between two antennas,
co-phasing will give you a 3db gain,
(when done correctly) 1/4~ antennas HAVE to be
placed a 1/4~ apart or else the near-fields will overlap and any gain you
hoped to produce be lost.
Don't waste your time my friend, you will get better results with 1 antenna
mounted in the center of the roof!
Go with a Wilson Lil Wil.
Co-phased antennas look cool but don't work and will
actually decrease the performance unless set-up correctly.
a 1/4~ is approximately 9ft. or 102".
--
Mad Dog

"PES949" wrote in message
...
I am thinking of getting a Twin Trucker for my Ford Explorer...

I would mount the antennas to the roof rack and run a ground wire since
the
racks have a rubber gasket to prevent leaks. I also want to use springs at
the
base in case I get some low branches etc.

Will the springs hinder the quality of the signal? If so, is it marginal?
Is the ground wire idea ok?

Rinning a Cobra CB.