On Aug 25, 6:14 am, Tim Shoppa wrote:
On Aug 23, 3:39 pm, laura halliday wrote:

On Aug 17, 6:12 pm, mrhaney wrote:

I am looking for a few (10) diodes 1N270...It is a germanium and used
in Double Balanced mixers in SSB generation..Most suppliers have a $25
to $50 min order and I don`t care for that.. thanks Harold W4PQW

So after all that, any hints on what the original project was? Even
in the 1970s people were speccing matched silicon diodes (e.g. 1N914)
or hot carrier diodes (e.g. 5082-2800) for mixers.

At least two volumes of "Single Side Band for the Radio Amateur" and
many ARRL handbooks from the 60's show 1N270's used in balanced
mixers.

It was a jellybean of the time, it's odd that someone would not
realize it and slavishly want to use it rather than something more
readily available (and performance-wise far superior) today. Probably
the same guys who insist on carbon-composition resistors everywhere
today too :-).

There are some things that appear in old construction articles that
are worth finding. For example, the BC-453/454/455's tuning capacitors
and drive mechanism are truly superb and I still keep my eyes open for
them today :-).

Tim.

Indeed. I have several old ARRL and RSGB Handbooks and a
number of older references (including Single Sideband for the
Radio Amateur).

You can see the fashions change. At one time the cool part to
use was the 7360 beam deflection mixer tube; at other times the
challenge was to see how many 40673 MOSFETs you could use
in a single radio. Many of these designs are difficult to reproduce
now.

I'll see your BC-455 tuning capacitor and raise you an Eddystone
dial. :-)

You can make nice radios by applying the right technology to
the problem. My recipe for a stable VFO nowadays is a
postage-stamp size surface mount board mummified in bubble
wrap and stuck to the end of a good, solid air variable capacitor.

Laura Halliday VE7LDH "Non sequitur. Your ACKS are
Grid: CN89mg uncoordinated."
ICBM: 49 16.05 N 122 56.92 W - Nomad the Network Engineer