From memory, most of the wire used is "Cable, Electric, P11" and this is (I think) still in current use - it certainly turns up at various surplus dealers.
It's a tough rubber sheathed multistrand tinned copper core cable, as used for the feeder on the various wire aerials issued with the truck & ground station.
If you look in the Parts Identification List EMER (FZ256-3) that gives you all the (admittedly 80 year old) component details and the lengths of cable used.
Somewhere I have a (British) No.7C cable and it does look like an exact match for the drawing, but I can't go looking for it at the moment. ("Stay at home, keep warm, and rest." said the Doc, after the cold I developed as soon as I booked a week off turned into a chest infection that hasn't yet cleared up.
)
The 7C feeder has 6-feet of P11 cable with a side-slotted 5/32" 10 amp solder lug fitted to the mast end and a "Clinch" (crimp?) 15 amp, 3/16" hole lug at the set end (plus the Plug, Aerial, Single, C1 and associated fixings).
The two aerial feeder assemblies I did find were for the WS38AFV and have a smaller (and slotted) plug on one end and a Ross Courtney terminal for the aerial base on the other, so that was no help.
I'm trying to remember where the correct aerial feeder is likely to be hiding....
Chris.