In article , Reinhard Zwirner
wrote:

good that these stuff is available from half a dozen sites for free...

Where?

Very interested

Reinhard-

I was hoping someone would answer.

These sites may not be what you're looking for but contain some references
to Heath. Check out:

http://www.circuitarchive.co.uk/heath.htm
http://bama.sbc.edu/
http://www.d8apro.com/heath1.htm
http://www.mods.dk/

73, Fred, K4DII