Originally Posted by BocaIII
The only way to be sure is to use an antenna analyzer.
I pretty much agree with Jack. If you look at where the steel
whip goes into the base, I suspect there is a set screw there which is used to tune the antenna + coax configuration with an SWR meter. It also looks like the base has a tuning coil in it so you cannot just take a measurement of the length of the whip and figure out where it is resonant.
Anyway, if you have an SWR meter available I'd hook it to where it will be permanently mounted and just check it how it is. If it is way out of tune it may be able to be adjusted but it depends how much and in what direction, and if you have an antenna analyzer you can borrow it is even simpler still.
I'd write more but have a list of honey-do's I have to get back to!