Akg D558b
Hi, Dan; just joined the forum to reply.
Just discovered an AKG D558B attached to some old local radio comms gear. I've now connected it up, and it clearly appears to be a noise reducing mic., which means that noises from more than an inch or so from the mic. are vastly reduced in level, to allow communication from a noisy environment.
Now I am going to do more research - I'll let you know what I find, if anything.
Cheers,
Terry Meadowcroft