I like old test equipment (especially valved equipment), and have a small
collection of it. I find mantaining the test equipment is often just
as much fun as using it; except when to solve a small problem I find
one piece of equipment is broken and I reach for the scope to fix it
and then find that that doesn't work either, and before I know what I'm
doing I'm off on a chain test equipment fixing marathon!
My most interesting piece is probably a BC221 heterodyne
frequency meter, built for the american air force during World War II.
It has alas had the valves removed, but I'm in the process of putting
Marconi Equipment List
Marconi test gear dating from the valve era in general seems to have been
built to a very high standard and often survives to this day in working
order. The same cannot be said for the manuals. Hence I've been compiling
list of such equipment with details of ranges,
and applications. The list started off from one in the back of the
RSGB publication on Test Equipment for the Radio Amateur by Clive Smith
(G4FZH); but it's been added to in light of the equipment which I now own.
HP Equipment List
With HP numbers as annoying as Marconi ones, this list also aims to covert HP part numbers into real life
descriptions of the equipment. More annoying still with HP is their habit
of using non standard part numbers for perfectly standard components.
These are usually to be found in the 1820 series. Fortunately some
chips have both an HP number and a real number on them, and some service
manuals give both. Hence a list of equivalents
can be compiled.
Xerox have a similar annoying habit of relabelling ICs, some equivalents
may be found in this rather short list.
A schematic drawn and (badly) scanned by me of this early design
of potentiometer is here. It was
designed for measuring temperature in a portable way when combined
with a thermocouple. The instructions are amusing in that they
suggest `Cabling for a replacement' should the galvanometer break.
It is currently broken, but I doubt cabling would be of much