A web scrapbook by Michael Saunby
A selection of old electronic things I've found, collected, restored, built, dismantled, read about or encountered in some way. There are other pages on the site with projects using current technology such as the MSP430 microcontroller and Nokia Internet Tablets.
These are quite commonly collected and the better sets combine high quality electronics with stylish furniture. The most sought after tend to be those made in the 1920s and 1930s. Later mass produced sets are often less interesting and less attractive, but there are some nice ones to be had - some 1940s sets with bakelite cases are popular with interior designers, and some FM receivers from the mid 1950s can sound very good.
Almost certainly the "golden age" of wireless. The superhet, indirectly heated (mains) valves, permanent magnet loudspeakers and other innovations of this period gave sets that can still perform well today.
Wartime "utility" and post-war austerity made its mark on set design.
Miniature valves and FM broadcasting kept development going despite massive competition from television.
The transistor arrived in the 1960s, but valves kept going for a while.
Are fairly easy to build, don't require lots of test equipment and can be used and enjoyed every day. Though the voltages involved might kill, so read, practice and THINK before trying to build or repair valve kit.
Places to learn more about valve amplifiers
The best valve of all, if it can be obtained, is probably the Mazda ACSP3. This was designed with a special view to low hum and microphony, and is widely used by the B.B.C. for microphone amplifiers. Even with this valve it is found that individual specimens vary in their hum properties, and selection is again desirable.- P J Baxandall. Wireless World, Feb 1947
Very much not my specialism but an amazing invention that over the years provided pretty much all technology behind radio, audio and computing.
Try these other websites -
Digital Radio Mondiale (DRM)
This looks like an interesting use for vintage tuners and receivers such as the Sound Sales DX Plus One.
I'll need to convert the signal to a 12kHz IF. Here's a circuit using a FET - how modern! I think I'll stick to a good old triode-hexode.
Here's a more sophisticated converter using the SA602 http://users.belgacom.net/hamradio/schemas/DRM_455kHz_to_LF_Converter_FRG-100.htm
There are sample files here http://www.g7ltt.com/drm/
and using one of these I was able to check that my install (on Ubuntu) of Dream DRM Receiver was working.
Info on using Dream software here http://www.fineware-swl.com/drm.html
To comment on anything on this site please leave a note on my blog - Michael Saunby