Looking at the 1958 Amperex book and cross referencing that with Frank's tube data. It appears to be an HF-300. Their data says it substitutes for the older 204 type. Thanks, Durff -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20180115/7dacbe57/attachment.html>