Homebrew Turd® RF Power Meter / SWR Meter

Outside case shot. It is built into an old California Amplifier MMDS downconverter case. You can see the 50-ohm load on the top connector.

Nokia cellular phone directional coupler overview.

Nokia cellular phone directional coupler closeup.

Microampere meter ballistic adjustment potentiometers.

Prototype overviews / notes

Overview of the wattmeter showing the directional coupler and the 50-ohm load.

Diode detector side of the directional coupler. This particular board and diode where taken from an old brick-style cellular phone. The little module board has all the necessary components aleady installed.

The actual directional coupler. Frequency response should be good from to a few GHz. Power handling should be that of a typical cellular phone, which have power options from a few milliwatts to +6 Watts. The coupling factor isn't known.

Picture of the coupler hooked to a analog microampere meter.

Internal view.

Another internal view. RF input/output is by the BNC connectors on top, the switch toggle between two 50k Ohm potentiometers to select low and high power modes.

Directional coupler and detector diode from a Nokia cellular phone.

Directional coupler and detector diodes from a Toshiba cellular phone. This one has two coupler ports for measuring power and SWR.

Directional coupler and detector diode from another Toshiba cellular phone.