"Frank Gilliland" wrote in message
...
Everyone will think I'm insane for saying this, but Landshark has it
right.

No he doesn't.

In order for co-phased antennas to achieve that ideal figure-8
pattern they must be nearly ideal antennas, which CB antennas are not.

They don't nessessarly need be to be ideal, but the do need to be installed
the same way. By the way no antenna is ideal, but many people have a lot of
success anyway.

Landshark's link explains why this happens. I wouldn't expect any
significant improvement in the omnidirectional characteristics of
dualies (as the site claims), but I do know they don't provide any
noticable directional gain.

If you check the link I provided you will see there is some gain. The gain
does not become noticeable until you have at least a 1/4 wavelength
separation, and at that it is around 2 db or so. On the site I posted the
link for you will see the figure 8 pattern becomes very noticeable for a
half wavelength between antennas. Getting to that degree of separation is
much easier to do on a semi because of their size, and the fact the antennas
are further apart from being mounted on the side view mirrors. Passenger
vehicles just don't have the size needed.


--
Leland C. Scott
KC8LDO

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