mister35mm wrote:

1. Ok, easy question first. Someone has given me a PCB for a QRP
transmitter called "little joe" and the PCB has 9-81 QST. I have
searched on the web but I cannot find the component layout, and,
ideally, a copy of the original article.

My QST collection only goes back to '88 or so. You could buy a CD from
ARRL, if no one here has the article.

2. I have been playing around with a simple transmitter project called
the Michigan Mighty Mite ( http://cs.okanagan.bc.ca/ve7ouc/eng/kc6wdk-
mirror/transmitter.html ) which uses any one of a number of small
signal NPN transistors. As I found a large number of metal cased NPN
power transistors, I was wondering if I can drop one of these as a
direct substitute for say, a 2n2222, or an old BFY51 etc etc. I have,
for example, found a RCA 2n6282 Darlington Pair in my junk box. This
is a VERY meaty little beast. The datasheet for this tranny can be
seen he- http://www.datasheetcatalog.com/datasheets_pdf/2/N/
6/2/2N6282.shtml

Any suggestions?

Don't do it!

Power transistors, particularly vintage ones, are very slow in
comparison to "small signal" types. Darlingtons are a different kind of
thing altogether, they are even slower yet but with significantly higher
current gain.

Find a bag of surplus 2N2222s, or buy a dozen new 2N3904's from Digi-Key
-- you'll be much better served.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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"Applied Control Theory for Embedded Systems" came out in April.
See details at http://www.wescottdesign.com/actfes/actfes.html