I found this on another forum. All I can say is WOW!!!!!
Thanks to the guys that put all of this information together.
__________________________________________________ __________________________________________
Perry Sandeen has finalized a remarkable work on the Hammarlund SP-600
and its many variants. This has been a long process with input from
many different people who all had something to share on this fine
receiver.
It is available for download (free) on the Hammarlund Historian
website. It is in .pdf format and in two parts, each being
approximately 7 megs.
Look he
http://www.hammarlund.info/