Find a local amateur radio operator, 90% of them have what
is called an antenna analyzer made by MFJ. If he or she has
not gotten one they will know someone who has.
Once you hook the analyzer to the coax it will tell what
frequency range each antenna is for sure, no guessing
only fact.
Also remember the longer the antenna the lower the
frequency, the shorter the antenna the higher in
frequency it is...
You can "cut" an antenna in 1/4 and 1/8 wave length
to make them resident/work but you cut the efficiency
as well.
The rule of thumb is the more wire/antenna you have
the better receive and transmit you will have. Your
antenna is 99.9% of your radio system, the radio is
.1%. You can have a $1000 radio and a $.50 antenna
and your system will preform and sound like a $.50
radio.
The other thing that people forget is grounding,
grounding increase the chance's of you system to
run at 100% efficiency, it also is a good safety
thing so you won't get shocked..