Grundig Majestic 9070 radio antenna shtuff...

I recently came across a Grundig 9070 which has a Mono, but awesome record player, fm and sw and a reel to reel (which doesnt work currently).

http://www.goodietwosleeves.com/forsale/grun01.jpg
http://www.goodietwosleeves.com/forsale/grun02.jpg
http://www.goodietwosleeves.com/forsale/grun03.jpg

It even still has all of the schematics, warranties, manuals, etc

http://www.goodietwosleeves.com/forsale/grun04.jpg

We love it's warm, rich sound and we actually changed out the needle cartridge in the record player so we can still play all of our more current vinyl without issue. Anyhow, I've been trying to improve our FM radio reception and I want to be totally sure before I start fiddling with it's guts. I'm basically wanting to hook up either a powered indoor, or regular outdoor antenna to the thing, but I'm not 100% on where. I assumed I could allegator clip a wire directly to the copper wire taped to the inside top of the unit, (which is ghetto I'm sure) but I noticed in the manual (mind you it's 50ish years old) it suggested I contact my 'dealer' to install an outdoor dipole antenna. There's actually a plug in the back and everything, I just need to know what the best course of action is.

Here's a shot of the plug in the rear of the unit. The wire I'm holding runs into a small box just out of my view inside that then turns into what I think were 2 short copper wires.
http://www.goodietwosleeves.com/forsale/grun11.jpg

Does that plug look familiar to any of you? Did one of you guys use to be an authorized dealer with a spare outdoor diode antenna I could purchase from you? Haha. I've been lurking on here for a while as I had the phono fixed and I know you guys are brilliant with this stuff, so any help would be greatly appreciated!

I have another issue with the record charger function but I should probably post that query in the appropriate forum area!

It takes 300 ohm twin lead to a TV antenna.