If you read the document that picture comes from, you will know...

Thanks!

I've googled the image with "300 ohm fm connector".
But it's almost the only image on google with this connector.

Seen over 9000 now :) 

aymeric wrote:

But it's almost the only image on google with this connector.

I must've done something right then

Just to make sure, it's DIN 45316, but it may be useless trying to find it by that name. Just a few days ago, I believe somebody posted a German source for wire antennas with that connector on the forum. It seemed to be a molded connector though, so it might not be too useful if you are trying to repair a rabbit's ear antenna.

Just for the record, with the replacement of the plug, I'm using the very same rabbit ear antenna with a BS2500 with pleasure (of course with a replacement plug).

This is a little piece of evidence for B&O's timeless design and ideology, as this antenna can be connected without any problem to a long later designed B&O system.