The problem with power transistors is that they are big, and all other
things being equal, more size spells more capacitance, and mosr capacitance
spells more trouble at higher frequencies.

Chances are, you might do some good with some of them on 80, but you're not
likely to make them play nice on 20. If you notice, the 3055 has an Ft of
2.5 MHz, 3054 3 MHz. The 2N2222 has an Ft of 250 MHz, so you can see
there's a little difference there.

Your 3739 has a 10 MHz Ft, so you might get a little gain out of it on 80.
The 2SC895 I *think* is 20 (could only find a bad copy of the datasheet).
It will take a fair bit of tinkering to make parts like that work at all,
and they won't work well.

...

"mister35mm" wrote in message
oups.com...
OK OK boys... yes I know 2n2222's are wonderful and plentiful, but I
have a heap of geriatric bipolar power transistor I thought it might
be worth experimenting with:-

2n3055 (three)

2n3054 (four)

2n3739 (two)

2n4800 (one)

Sony D292 U38 (two)

Sony 2sc895 (one)

I thought if you can get anything up to 500mW with a general purpose
NPN, then what can you get out of an old power transistor?

I also have a load of BD139 medium-power transistors...?

Any thoughts?

In addition, I am still looking for the COMPONENT LAYOUT for the PCB
for a QRP
transmitter called "little joe" described in 9-81 in QST. I am not
looking for just the circuit diagram but where the parts GO on the
PCB!

Stephen G7VFY

07956-544202