How to connect Sennheiser MKE shotgun to Sony TCD-D7 DAT recorder?

Hello again.

I want to connect my shotgun mic to my portable DAT recorder in order to
tape the dialogue in a friend's short film.

I'd like to mount the mic on the end of a 'boom'. The mic has a 3.5mm mono
jack on the end of a 14cm curly helical cable. The DAT recorder has a 3.5mm
line in socket so my question is:

What type of cable do I need to connect the two devices and how long can the
cable be before the signal starts to attenutate?

Many thanks,

KJ