I found this at a flea market today, it looks a typical PVC balun with
so239 female on the bottom but has 35-50 foot length of 300 ohm twin
lead TV cable coming out the other end, it says:

The Jim Black Balun
air wound 2kw pep
with low swr
1.8 - 30mhz 1:1 ratio
by wa4ytu - Jim Black

it looks like you hook your coax to the female connector, but how do
uoy rrun the 300ohm
twinlead? horizonal, vertical or does it have to be cut to length? I
cant find any instructions
on the web for this balun/antenna.