ESP8266 WiFi Field Strength Meter

Mike, KJ4Z recommend that I try this board for and idea that I have, which is a wireless remote field strength meter.

A simple field strength circuit would put out microvolts, and this board can take that voltage and then send the value back to a central server or app running on my laptop that takes the value and plots the values on a display.

Several of these can be distributed around an antennas near or far field and then you could have multiple points to record the antennas pattern. A GPS shield would be added so the location of each meter could be mapped in real time. Adafruit has such a wee beastie:

Adafruit GPS “feather”

The Adafruit GPS feather doesn’t work well with an 8266, but they have several other “feathers” that it would work with. SO, the field strength meter would have a loop that constantly polls the voltage from the simple germanium diode circuit (modern day “coherer”) reads the GPS coordinates and then transmits these 4 or 5 numbers to my home WiFi. I say 4 or 5 because with GPS, you need three coordinates for a location, and a fourth could be used if say, you wanted altitude – such as when using this on a drone. SO – a max of 4 GPS coordinates plus the micro voltage reading. The values would be transmitted and I would simply have a program that logged these values into a CSV file.

Today I took two Arduino programs and mashed them up – one logs into my network and pings an NTP server for time updates and the other writes the output to the built in OLED. This was a test to make sure I could manage the WiFi as well as the OLED – since it would be cool to display something at the meter – like a continuous voltage stream. Right now I have a heavy analog meter in my home brewed field strength meter – but for a drone – these “feathers” are light enough and can run off a watch battery – so could easily be the payload with a light wire antenna dragging like a Zepp antenna.

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