Hopefully this is an easy one which I can get an easy answer for.
I have a mini-magmount whip type antenna for a mobile VHF transceiver (the ultra mini footprint magmount diameter~2cms). I am using the radio at app 169 MHz. The antenna is a very simple whip design, there is no coil or loading in the base simply the aerial whip.
My questions are several-
1. What length should I trim the antenna to? (is it simply 1/4 the actual wavelength for this frequency or is it more complicated)
2. Is it worthwhile trimming the cable to a mulitple of half
3. As the whip is held in place by a small grub screw and can be adjusted up and down, is the ideal whip length what is visible above the mount or the whole length ie including the bit of the whip inside the mount?
4. There is no end cap for the aerial, does this make a difference?
5. What should the coax screen be connected to at the mount? (the base of the mag has a non-conductive cover so I take it theres no way of making a direct connection to the car to make a ground plane or am I way off here??)
6. As the results don't have to be perfect (it's not that critical) is it worthwhile buying a SWR meter for a one-off (my other radios are all handhelds) or can I get reasonable results without one?
Hope I'm not sounding too stupid here,