[SOC] Matching G5RV

[Paul Bartlett]

Hi All,

I have a conundrum to solve.

I have a K2, a full size G5RV (104') and an ex-miltary ATU (Redifon type
A.C.U.9) kindly loaned to me by Paul MW3PWA.

The ladder-line phasing section of the G5RV terminates in a 50R co-ax
connector and is immediately followed by a 10 turn co-ax 'choke balun'
(about 6" in diameter). There's then a 30' run of co-ax to the shack.

The ATU takes an RF input via a BNC connector which runs to the K2.
Disassembling the ATU I see that the hot input passes to a bank of
switchable capacitors down to  ground and thence to variable series inductor
(rather nicely made).

There are three output terminals: Earth; the other end of the inductor; and
a third terminal connected to the second via a high-voltage cap which value
I can't determine.

Questions:

Is the ATU sensibly usable at all with my mix of antenna and feed? If so,
how?
Do I need a further balun after the ATU to match the unbalanced feed?
Should I ground the ATU via it's EARTH terminal?

Any and all suggestions welcomed.

Best,

Paul M3CRQ :-)