The GSA stands for Ground Spike Antenna. In RF engineering terms, its a base loaded half wave vertical. This kit comprises a spike, to mount the antenna in soft ground, a base unit, containing the loading/matching coil, a 6m long coax feeder, a short 40cm or so adapter coax for use with the PRC-350 radio, ten antenna rods, and a nice bag to keep them all in.
The original, and most common, version of this has a number of long antenna rods. This version has short rods, and twice as many of them! The idea is simple - put the rods together to give the element length needed for the frequency of operation.
I'll probably have a play with this live tomorrow. By running the analyser over it with each combination of elements, i'll be able to form a nice accurate table of element numbers, more accurate than the specified three lengths.
The 'test bed' PRC-320 is now opened up on the bench, the PSU module 5 removed and opened, and the covers off Synthesiser module 9, ready for the HV capacitor replacement tomorrow. I have a new bit for my soldering iron with a much finer tip, much better for this sort of work than the supplied chisel bit!