Strange Aerial connection

I've got an old Aiwa Reciever, probably dates back to the 70s or early 80s -
massive heavy aluminium front, needle tuner etc. Anyway, it's got a rather
strange connector on the back for the antenna - 3 holes in a row marked "FM
Aerial". Any ideas on what I should be hooking up to it?

This might be it

Send them an email with a photo and they may be able to help you.

Oh come on you lot, where have you been these last 30 years.

Its one of those plastic connections that come on the end of the pink
aerials we are so fond of. The outer two are for the signal and the
centre is just a plastic locating pin.
The AM version is the same with one of the outers at an angle. Can't
you still buy these ????

I would just stick two long wires in the outer two and hang them
decorously over the picture frame. If you don't have a picture frame
find a friend to hold it up.....

Guess it's a 300 ohm balanced (ribbon) input with the centre being ground.
For 75 ohms co-ax use ground for screen and one of the other connections -
it will be near enough a match.

A FM aerial? :-)

I suppose it might be a combined 75 ohm/300 ohm connector. Try your
FM downlead into any pair of holes, see which work best! I suppose
it might be worth looking for a voltage on any of the holes first,
just in case it's some special arrangement for e.g. powering a
mast-head amplifier.

My guess is that the outer two are for a 300 ohm balanced downlead with
the centre pin being ground. If so, then either connect a balanced lead
to the outer two pins, or a coaxial cable to either one (not both) and
the centre pin. It would be as well to check for volts as Lawrence has
suggested.

What's one of them then?

What's one of what?

A 300 ohm balanced downlead.

This is a cable which has two parallel conductors spaced about 2 cm
apart. Unlike Coax, it doesn't have a screen. It is used mostly in
continental Europe. It has a characteristic impedance of 300ohms, and
having two identical connectors, is balanced, hence 300 ohm balanced
downlead.

It's not something you can buy easily in the UK, and indeed, coax is
preferable, as 300ohm cable is susceptible to interference.

I would use coax, and connect it to one outer terminal and a ground
point, typically the chassis of the receiver, or the centre pin of your
socket if that is ground connected.

Hope this helps

Oh, don't be so helpless! Bodge it! :-)