Have you considered a Vector Network Analyser? They are much more 'informative' than a conventional antenna analyser. The disadvantage is they tend to be less portable as they generally require a PC, ideally a laptop if you want to do work outside. I have a miniVNA Pro, which covers up to 180MHz. There is an Extender to go into the GHz region and a newer model which does up to 3GHz as standard. Mine has a Bluetooth interface and internal battery so you can dispense with the USB lead. You can plot an amazing number of antenna characteristics plus do things like set up filters, measure L and C, Coax loss, length, measure/setup 'stubs' etc. I note others have been less than complimentary about the MFJ products but the 259 is a reasonable, basic, analyser in my view. I use one for some 'quick' measurements. Mine is one of the older models so its functions are more limited but I still find it useful.