Jack,
As stated, the only answer anyone can make to your
questions is, [2] I don't know.
SWR meters and antenna analyzers are nice, and handy,
things to have around, but they require a little thought
in their use. They aren't the "be all, end all" of
antenna instruments by themselves. Probably the most
'handy' measuring device for dealing with antennas is the
yardstick (or meter stick for those that would rather).
Antenna analyzers are probably the most 'handy' gadget
for finding out band/frequency an antenna is made for
that I've seen in years. But, and there are several 'buts'
that have to be taken into consideration when using one.
If you connect an analyzer to the feed line of your antenna
you are measuring where the whole 'system' (feed line and
antenna) are 'resonant', not just the antenna. The feed line
'modifies' what the analyzer 'sees' of the antenna, changing
the answer to, "What is the resonant frequency, and the input
impedance?". To make the antenna 'right', you have to get
rid of the feed line. OR, make it 'disappear' electrically.
You can do that by making the feed line an electrical 1/2
wave length at whatever frequency your antenna is supposed
to work at (or multiples of an electrical 1/2 wave length
if one isn't long enough to reach from the antenna to where
you are doing the measuring). The analyzer readings then
are for the antenna only since an electrical 1/2 wave length
of feed line is 'invisible' to the analyzer. (Takes a different
feed line length for each band.)
**[A thought about 'efficiency' here. Don't worry too much
about
efficiency, it isn't that important really. Of course you want
the most efficient antenna you can have, but that can change
with
any number of things, even with the exact same antenna. (Watch
the
fur being rubbed in the wrong direction with that statement!
LOL)
I'm talking about efficient 'results', not the characteristic
efficiency of a particular antenna. An antenna should be
mounted as
high as possible, away from anything around it. But, you can
only
put one in the space you have available, not always what would
be
the 'best' height/clearance, (right?), so make the best of what
you have and live with it.]**
Use that yardstick to measure the length of your multiband
antenna's elements. That will give you a rough idea where they
'should' be resonant (barring any loading coils, that makes
it a little more difficult). Plugging those lengths into the
'magic' formula, F = 234 / length(feet), will give you a 'ball
park'
idea of frequency for 1/4 wave lengths (one half of each
antenna).
Then it's just a matter of 'tweaking' the lengths for each band.
That doesn't do anything about input impedance, just resonance.
To
match the input impedance is a separate thing, and there are
several
methods of doing that. When both length and impedance matching
are
done, you will have the most 'efficiency' for the antenna in
~that~
particular configuration. It may not be exactly what you want,
but
that's more a result of how/where the antenna is mounted.
Anything and everything can change the usefulness of an
antenna,
which is due to the radiation pattern, which is/can be affected
by
how/where/when the antenna is put up (at night, in a snow storm,
at
the North Pole is the best 'when').
Having used 10 words where 2 may have been more 'efficient',
I'll
shut up...
'Doc

PS - A mobile antenna is usually only around 3 - 20% efficient
compared
to a 'properly' set up fixed antenna. They still work okay.