[Premium-Rx] General Coverage Antennas for HF

Richard Reich richard.reich at saatt.co.uk
Mon Feb 2 07:22:51 EST 2004


An improvement to this circuit....?

It seems to me that the linearity and performance of the whole amp is determined
by the first stage. For it to behave as a super-linear amplifier, the drain of
the input E212 must `see` an infinitely high impedance. 
Although the bipolar device is good (giving about 2%-5% current stability) - it
can be much improved upon with other methods.
I would replace the bipolar transistor constant current source (2N3906) with a
constant current generator circuit using an IC. 

I suspect the IP3 will be further improved, and will give this a try when I have
a moment.

For the very high value resistor - I have measured some IC ESD packaging plastic
- which might work. 

Richard
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Richard Reich    
Principal Engineer Hardware
SAAT Technology Ltd
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