On Wed, 02 Mar 2005 06:40:53 +1100, Bob Bob
wrote:

- You live in very flat country?

Not particularly flat ... (MA)

- Dont use directive antennas on the mobile (eg a quad/yagi) as most
comms on VHF/UHF happen by reflection once you are beyond LOS and in clutter

Right, I should bave been more clear, I'm looking for an
omnidirectional vertical.

I once had a Hustler 2-meter collinear, something like 5 db gain
omnidirectional, and five feet tall or thereabouts, with a 3/8x24
mount. Never had a better 2 meter mobile antenna before or since.
But, it only comes in a monoband version, and only 2 meters and 220.
If I could find something dual-band for 2 and 440 that's as good as
that one was, I'd be happy.

CJ

Gee I am gong to have to learn those state abbreviations... So many of
them start with "M" grin

I use to work on UHF radio equipment installs being used on the flat
areas in western NSW (Australia). One of the common setups was a 9dB
fibreglass whip (476MHz - about 6ft long). It had to be setup just right
otherwise the few degrees of tilt you got from air movement would lift
the pattern in front of the vehicle above the horizon and make it all
but useless.

I also hear that 1/4 wave whips are almost essential if you are driving
amongst high rise buildings.

Also did some tests recently on the "gain" of a vehicle mounted 1/4 wave
vs a test dipole antenna at 4 metres height. There was about 10dB
between them, we assumed because the 1/4 wave was still very much in the
ground clutter. This was on 149MHz and LOS.

My view is that any dual band antenna is going to be a huge compromise
anyway and high gain on both bands unlikely. I am however prepared to be
shot down over this!

Apologies for waffling on!

Bob VK2YQA

C. J. Clegg wrote:
On Wed, 02 Mar 2005 06:40:53 +1100, Bob Bob
wrote:


- You live in very flat country?


Not particularly flat ... (MA)