Tuesday, February 18, 2014

Mixer and Amp Performance Measurement

I took my Homebrew Mixer and Amplifier (see previous posts) to Jacks Homebrew Meeting tonight. I was hoping that Jack and his Lab could help provide meaningful measured performance data.

Jack has several very nice pieces of LAB Grade test equipment. Unfortunately, his tracking Oscillator-Spectrum Analyzer was missing a cable or not working, and could not be used.

But with other equipment, we were able to spot check performance with an HP Oscillator with Attenuator and a HP Frequency Sensitive Voltmeter with its Attenuator. The two attenuators agreed within 0.25db. We also had a standalone attenuator for gross signal level adjustment.

The results; the Amplifier measure about +30db gain from 1 to about 27MHz (which was the highest Freq the Oscillator was calibrated for). The Amplifier would "quiet" the Voltmeter with as little as 115dbm input signal. Actual Noise Figure performance was not measured. This overall measured results are similar to what LTSpice suggested, but less than I measured at a Load on my Oscilloscope. NOTE: I may be mixing in my mind; Power Gain with Voltage Gain performance data, I may need to rethink this measurement.

The Mixer performance data and method was less precise, and accurate measurement will have to wait until Jack has his other equipment working.

More performance testing is necessary.


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