Very correct, this is a spoke. It doesn't necessarily have to be a military radar. It must be one on the same wave length. Obviously it could be a same type.
If a radar sends out an electronical signal, it happens from time to time that it "shines" into your radar for a split second. That's what you see on your radar. In heavy densitiy flying area like Europe or USA, thise spokes are not uncommon.
Dani