Hello Tony

from scratch and try and design a unit but this would save me a heap of
time. It appears that ATN is long gone. Any help would be greatly
appreciated. I have quite a collection of amateur radio related service
manuals in pdf and or jpg format so maybe i can return the favour.

You might get some help trying this

http://www.fortunecity.com/skyscrape...5/LogCalc.html

Regards Max