My vehicle is tiny - 12 feet by 5 feet approximately - it will never provide
a perfect ground plane. I use to have a Land Rover Discovery which was
better. When stationary I used to use a set of battery jumper leads to
connect the vehicle to the nearest wire fence or metal handrail. Could give
a full 6dB improvement on 80M or 3dB on 20M. Best ever was when parked on
a quayside next to a derelict steel hulled tugboat. Connected my jumper
leads to the hull, tuned up the antenna and gained two whole S-points. I
also noticed that on the higher bands such as 20M there was a definite gain
when close to the sea or wetlands but that is probably reflection. I have
never monitored the matching whilst mobile but guess it changed dramatically
when passing trucks, buildings, bridges etc. At best all one can do is
compromise.
Dick

"Channel Jumper" wrote in message
...

The only people that worries about SWR is CB'rs.........

CB'rs only has one half of one megahertz to play with - hence antenna
tune is critical.

If all you are going to play with is one frequency or one band - then I
guess you are going in the right direction.

The missing information that my crystal ball is not clear on is the make
and model of the vehicle and antenna.

With HF it is more important to have a large metal ground plane - large
Suburban sized vehicle, that has all of its surfaces physically bonded
together with a wide copper braid straps at all hinge points and corners
- such as a pick up truck front walk away, hood, doors, cab, bed,
exhaust, engine, transmission, exhaust, suspension etc..

It's more important to bond these surfaces together then it is to tune
the antenna so it looks good on the analyzer.

At the same time, the ground conductivity changes as the vehicle moves
down the road, so unless you plan to never move the vehicle again and
operate from that one spot - the tune of the antenna will change with
the earth as you travel down the road.

Hence it is not as critical to get a perfect match in a vehicle as it is
using a home install that is not going to move once it is installed.

Can you see my point?

If you have a small plastic car - forget about trying to get a perfect
match.




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Channel Jumper