On Nov 30, 10:02*pm, richard wrote:
On Sun, 30 Nov 2008 08:05:31 -0500, "Douglas W Adair"
wrote:

I like them two at a time--co-phased. Is there any gain to be had that way
or am I just skin pipe dreaming at the petro?

Not much on a big truck.
Since most of the usable cophased signal is blocked by the cab and
trailer. I've found a single antenna works just as good.

What hurts the system the most, is the factory installed crap.
They generally use the smaller 75ohm cable and use splice after splice
to make it work. I generally get my own cable, bypass their stuff.

Since the feed point impedance of most of those antennas is really way
less than 50 ohms 75 ohm cable may not be the best choice to make a
phaasing harness. Most of the time 50 ohm cable works better