"Leland C. Scott" wrote in message
...

"Landshark" wrote in message
m...
That all depends on your goals. The typical dual antenna setup, when
done
right, generates maximum signal strength to the front and to the rear.
The
signal strength to the left and right is considerably reduced. The
same
applies to your receive signal strength as well.


Um, sorry wrong Leland, it makes the signal more omnidirectional.

If done correctly, spaced - phased - good ground plane, it works as I
described.

http://www.bellscb.com/cb_radio_hobb.../antarray.html



Long hual truckers normaly are concerned with communicating with other
truckers on the road. Those truckers are going to be either in front
or
behind them on the highway. Thus it makes sense to maximize the signal
in
those directions, and thus the popularity of the setup.

If your more interested in general communications in any direction
then
you
really don't want a dual antenna setup. What you want is an antenna
location
near the center of the truck, which will as nearly as possible, give
you
a
uniform signal in all directions. The site you picked, on the tool
box,
would be a good one.


Again, wrong Leland.

No. The site above has not only a discussion about antenna patterns, but
the
antenna field pattern plots to prove it. I can supply some EZNEC 4.0
simulation files to prove same if you want.


--
Leland C. Scott
KC8LDO

Feel free, but I guess Signal Engineering doesn't
know anything, right?

Landshark


--
That does suck..sometimes you're the
windshield..sometimes you're the bug.

"Landshark" wrote in message
...
Feel free, but I guess Signal Engineering doesn't
know anything, right?

They can't seem to get their facts right. For example:

" The pattern is "pulled" to areas where there is the most vehicle body. The
pattern is the worst in directions where there is no metal body for a
radial."

This is from their comment about mounting an omnidirectional antenna lifted
right off their WEB page. The dual antennas mounted near the mid point of
the vehicle should each have a similar pattern distortion due to mounting
location, for example to the front and rear with some to the side where the
antenna is mounted. Those are the directions where the metal is located,
with more to the front and rear than to the side. Now refer to the antenna
pattern for the site I mentioned you will see the greater field strength is
to the front and rear of the vehicle too for quarter wavelength spaced
antennas fed in phase, and is in the same direction. Both effects are adding
together in the same general direction. However under their comments about a
dual antenna setup they claim just the opposite in a round about manner.

--
Leland C. Scott
KC8LDO

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