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Hi Chris,
OK, I'll be around, ready to try a new configuration/bias, etc. Hope you get it figured out eventually.
Have a good trip.
73,
Steve

Hi Chris,
OK, I'll be around, ready to try a new configuration/bias, etc. Hope you

get

it figured out eventually.
Have a good trip.
73,
Steve

Okay, I see what I did here that made a mess of things. I had hurredly
adapted a two bipolar transistor circuit used for low power applications by
substituting a JFET for the NPN device and then changing the bias resistors
without properly thinking about it. With the JFET, it turns out that the
emitter of the PNP needs to be degenerated so as to accomodate the wide
range of Vgsoff of the JFET. Doing so allows me to increase the JFET drain
resistor so as to improve the open loop gain. The gain is now
around -0.5dB. And you can now vary the bias current from 5mA each leg to
12mA by applying a voltage to the JFET gate instead of changing out the
resistors as before:



Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ Sonoran Radio Research
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ IEEE Senior Member #40274515
. ( ) \
'-| )__| :. \ Email: christrask@...
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