Arduino Rf Power Meter

Rf power meter with arduino ad8307 and oled by rudi imbrechts on7ir january 2019.

Arduino rf power meter.

The project uses an arduino pro mini board whose adc feature is used along with the concept of ohm s law and voltage divider circuit to develop this wattmeter. Because my primary interest was for vhf uhf shf i have foreseen positions for 6m 4m 2m 70 cm 23cm and 13cm bands. This figure is calculated from the power vs voltage slope of the ad8307. As this monimatch type of bridge is frequency dependant the meter must be calibrated for every band.

Rf power meter with 1mhz 10ghz bandwidth and 55db dynamic. Rf power meter default function calibration 10 and 40 dbm for each band stored in eeprom. Code is based on sketch of mike richards g4wnc and adapted for use with an i2c oled display some display functions added. I have a 4 channel version module very similar to try out based on the ads1115.

The little arduino nano uses the forward and reverse dc voltages to calculate rf power and voltage standing wave ratio. In the arduino sketch i compensate for the loss in the rf tap by altering the intercept point used for the power calculation. Because my primary interest was for vhf uhf shf i have foreseen positions for 6m 4m 2m 70 cm 23cm and 13cm bands. Some parts do need a serial resistor some.

This sketch will readout rf power and swr from any swr bridge for example monimatch type. For the 2 048 volt reference you can use every reference chip you like. This is a project based on arduino board which can measure the power consumption of the devices. Current ratio is proportional to the ratio squared.

Using 10 1 turns would see 1 of the rf current at the reference resistor. Main arduino code that runs on the m5stack with graphics and buttons. It consists of from left to right the 5v power supply the arduino nano the ad8317 module and a 2 24 character module. They work really well 0 12v inputs 15 bit useful range.

The intercept point is the power input required by the ad8307 to give a theoretical 0v output. When we connect this wattmeter on to a device which is in operation the 16 2 lcd displays its power consumption value in watts. Arduino rf power swr meter. The sampling fractions usually is proportional to the square of the turns.