[Lowfer] Band conditions

[Johan Bodin]

Jay,

you wrote:

> [...] a heavy duty bipolar (50 mA idling current!)  2.5 dB noise =
figure
> 50 ohm broadband fedback preamplifier.


What kind of transistor are you using?

I have been experimenting with a number of broadband preamp's,
both the "classical" amp (with partly unbypassed emitter resistor plus
collector-to-base feedback) and amplifiers with "lossless feedback"
(called Norton amplifiers I think). I have tried a lot of transistors in
these circuits, including 2N5109, 2N3866 etc, but I am not satisfied
with the noise figure... I haven't tried FETs though..

A really good LF preamp would allow substantial reduction of loop
size... (for RX loops, that is :-)


73
Johan Bodin SM6LKM