I've had an MFJ-259 for about 30 years. I use it primarily for adjusting the length of dipoles and low-level tuning up of my antenna tuning units, the main one being an MFJ-969, but I have a few others as well. It is also fairly useful as a hand-held general purpose RF generator. The auto-leveling of the ouput over frequency ranges is pretty good, compared to my other RF generators (DDS, Si5351A, IG-102, Jackson 640, and homebrew 8640jr.) My URM-25D signal generator is better than those in many respects. I have actually used the MFJ-259 as a dip meter with homebrew coils, as it is handier than my AN-PRM-10 GDO. I was able to get a pretty good measurement of a pair of homebrew 20m coax traps.
The MFJ-259's measurement accuracy is pretty good for coarse measurements. It compares well with my Poor Ham's Scalar Network Analyzer for antenna sweeps, which has graphing capability.
That said, I'm about to buy a NanoVna, from Hugen's store, the 4" form factor. None of my equipment can get X directly, much less the sign of the sign of X. I'll still use the PHSNA for crystal characterization for homebrew SSB and CW filter design. The sweep range resolution of that is superior to the NanoVNA, 1 Hz step resolution if needed over as many kHz as needed. I'll probably use the NanoVNA mostly with PC output, as i do with the PHSNA. I'm looking forward to being able to measure accurately input impedances of devices. Ought to be a lot of fun.
Ted, KX4OM
