[QCWA] Slightly off topic, antenna sharing.

[Jeffrey D Angus]

Additional information:
This is the basis of the project.
<http://datasheets.maximintegrated.com/en/ds/MAX4014-MAX4022.pdf>
I had misread the data sheet on page 1, missing the fact that the
two 500 ohm resistors were internal. I added a pair of 510 ohm
resistors externally as well. The over all effect with the series 51
ohm resistor in the output is -4dB gain overall.

Note the use of 1206 form chip components and the adapter to
spread the leads on the chip out to 0.100" DIP spacing.

Connections to the BNC connectors are via 0.141" semi-rigid
coax. I jumpered the far end of the coax to the shell of the BNC
connectors to solve some instability issues (wide band oscillation)
when I mounted things in a chassis.

With -120 dBm into the amplifier, I could still see a discernible
signal on the spectrum analyzer at the output. Barely above the
noise floor, but the noise floor was due to the spectrum analyzer,
not the amplifier itself.

I'm tempted to go back now and just ground the inverting input
pins on the op-amp and see how it performs without the external
feed back resistors.

Jeff-1.0
wa6fwi