On Nov 30, 4:40*pm, "Hal Rosser" wrote:
If fed in phase and spaced correctly, there could be gain to the front and
to the back with a decreased propogation to the sides.
This is usually desirable if traveling on a mostly straight stretch of
highway. I think the spacing is a little too far apart for use on most cars.

"Douglas W Adair" wrote in ...



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?- Hide quoted text -

- Show quoted text -

I figure this is for an 18 wheeler on CB. In that case the dual
antennas make the patern more omni. Back in the 70s I belonged to a CB
club and we did some test of the effects of auto body styles on
radiation patterns. We discovered body stle and mounting location were
as important if not more so than the antena you were using.

An 18 wheeler with a single antenna mounted on a mirror has a really
ragged radiation pattern. Two antennas makes it a lot less ragged,
still a far way from being omni-directional.


Jimmie

I always wondered whether a short/loaded magbase antenna on the trailer
roof (so it doesnt hit bridges etc) would work better than a mirror mount...

How much roof to bridge etc clearance is there normally?

I would have a thought a DDRR would have been good too but I read
something recently that mentioned performance has never been as good as
expected.

Thoughts?

Cheers Bob


JIMMIE wrote:

An 18 wheeler with a single antenna mounted on a mirror has a really
ragged radiation pattern. Two antennas makes it a lot less ragged,
still a far way from being omni-directional.