Antenna analyzers are useful for adjusting and tweaking antenna systems for the best match at the frequency you are operating at. Z-Man and I showed the models we use at the classes in Wisconsin and Wyoming. They are different from an SWR meter as they don’t require you to key up your radio into an unknown antenna system, and risk blowing up the transmit final amplifier in your rig. If you are working with improvised and field expedient antennas, your commo section needs one of these.
This is the latest version of the classic, reliable MFJ-269 that I use. The ‘269 has been around since forever and a day. A little on the big side by today’s standards, but gets the job done. MFJ sells it for $300. You can get it new at Gigaparts for $270, and I’ve seen them in the ~$200 range at hamfests. A good choice.
Z-Man’s implement of choice is the newer Youkits FG-01. It sells for $270 new. It is a much smaller unit, but only goes up to 60 MHz. versus the MFJ’s top end of 230 MHz. This is also a good piece of kit.