Raspberry Pi Zero W Remote Field Strength Meter

Last year I built this cool little Field Strength Meter that uses a circuit from the 70’s and a germanium diode. It is plenty sensitive and broad banded – meaning it has enough voltage to send to the input pin of a Raspberry Pi Zero W – and which could then be sent to the shack via WiFI.

It would be easy to package such a gizmo – and then place several around my antennas so I could measure their patterns in real time. The more sensors, the higher the resolution.

I’m going to guess that this Adafruit Analog to Digital converter could be used to take the micro voltage that the meter receives and send it to the Pi. Then have the Pi transmit the value(s) to my laptop. I’d have to have an app on my laptop that could read the values and plot them in real time.

Using the Raspberry Pi Zero W has these advantages:

  1. I can use Python – or better yet – Adafruit’s micro Python
  2. The board is small and has wiFI built in
  3. It could be packaged and powered easily

The only worry is would its own WiFI signal swamp and overload the field strength meter? I think I’d have to have a Low Pass Filter so I only received HF frequencies – and not the UHF frequency that WiFI transmits on.

Well, waddya know – there is a Low Pass Filter board for the Pi – Cool idea – not sure if it could work . . . but it seems like all the ingredients are ready made and plug and play. Seems like the code would be trivial too – just read the voltge on a GPIO pin me thinks . . .

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