Hi Allison,
I was commenting about battery voltage range rather then current. Modern
three cell LiPos sag down into 11V range.
Some additional measurements at both 8 and 12 volt supplies.
For 12 V operation, change common base emitter resistor to 4.7k for 50
Ohm input. Ve=2.369V Ie=0.50mA. All else unchanged. Gain does not change.
Rough gain compression can be evaluated by adjusting oscilloscope input
and output traces on top of each other. Increasing input until output
trace sags with respect to input trace. Believe actual method is
measuring in an out voltages to find 1dB gain compression point.
Compression, using oscilloscope trace match described above is same for
both 8V and 12V versions, at about 12-13 mVrms input.
From this analysis, I see no benefit with the 12V version.
KK7B form is featured in ARRL "Experimental Methods in RF Design," page
8.13. Discussion for low-noise AF amplifier is limited to it having no
flaws and no additional design effort.
One flaw is CB emitter resistor for 50 Ohm input Z. Most everything
merits a revisit and possible improvement.
I hope Richard, original poster, is benefiting from these breadboard
measurements and study. Maybe reproducing these experiments for
conformation.
I found it to be quite educational! And fun to do.
John KN5L
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On 5/23/19 6:34 PM, ajparent1/kb1gmx wrote:
Hi John,
I can see field friendly easily.
The MicroR2 does about 55ma for the whole receiver on 40M.
That is without CMOS opamps (uses 5532).
Allison
