[Milsurplus] 1N21's and 1N23's

[Dennis Monticelli]

These are point contact (i.e. early Shottkey type) diodes that were graded
for freq and noise figure.  The 1N21 was Ge and the 1N23 was Si.  Yes, they
were fragile both electrically and physically hence the lead wrapper used in
some cases.  You can probably replace them with modern glass encapsulated
Shottkey diodes.

BTW, I've discovered that they make dandy crystal radio detectors.

Dennis AE6C