I would like to get one that gives an actual antenna pattern plot graphically,
This is NOT what a typical analyzer does: some can generate plots of impedance
over frequency, but to measure an antenna pattern you need some sort of remote
receiver and the ability to rotate the antenna while taking measurements.
That's not to say that you can't come up with a system that will generate azimuth
plots, because you can, but the boxes currently sold as "Antenna Analyzers" don't
The two easiest ways to create antenna radiation patterns are either to model it
in software (I find EZNEC fairly easy to use, while 4NEC2 is free) or to use one of
the plotting software packages connected to your receiver with a remote transmitter
of some sort as a signal source. The software then records the relative signal
strength as the antenna is rotated and plots it.
I use the EZNEC plots of my antennas when I'm designing them, then (particularly for DF
antennas where the pattern makes a difference) I set out a transmitter and rotate
them to check for unexpected lobes or nulls. I have plotted the actual pattern, using
either a step attenuator or a calibrated signal strength meter, but the quick check of
S-meter vs. direction is sufficient for detecting problems in construction.