MAFRX-35A Tube 80/75 Meter Receiver by JR1MAF

 This is an exceptionally well done web page from 2010 by Koichiro, JR1MAF:

http://www.mafnet.jp/roman/hamradio_forum/topic_31_e.htm

Although I've got no interest in using vacuum tubes his craftsmanship could apply to any ham radio project.  

One thing I thought was interesting was that he encountered (see it about 2/3 of the way down the page) some attenuation while using  a mechanical filter from an old Yaesu transmitter.  He took the cover off the filter and found that the foam rubber had started to disintegrate.  He cleaned it off with alcohol and the signals were better.

 

This foam rubber problem reminded me of my Heathkit HD-1250 dip meter.  I had put it away for a long time - after re-opening the lid a little shower of foam rubber particles came off the foam rubber pad under the lid.  This must happen to all of these kits, usually when there are pictures on the internet the foam rubber under the lid has decomposed and been removed like this one from ebay:

I just taped a hunk of Saran wrap over the foam rubber - hopefully that'll do until the tape lets go !

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm