I have been asked about compatibility of the RFPM2 current probe with the TinySA and variants. The current probe was intended for use with a broadband 50Ω RF power meter, but could also be used with a Spectrum Analyser with 50Ω input or an oscilloscope with 50Ω input. RFPM2 – current probe described a current … Continue reading RFPM2 – current probe – #4 – TinySA Ultra
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. This article describes its calibration and use with a 40dB 50Ω 20W attenuator to make a 20W or 43dBm RF power meter. Above is a pic of the system under test on a nominal 5W transmitter, indicating 37.4dBm, equivalent to … Continue reading RF Power Meter 2 (RFPM2) – 40dB external attenuator calibration and integration
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. The original LCD display was white on blue, but was very difficult to read at some viewing angles, so it had to go. Unfortunately I could not find more displays with that hole pattern, it seems to have been discarded … Continue reading RF Power Meter 2 (RFPM2) – display update
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. The project was used as the basis for a new project, and during that development work some improvements were made and ported back to RFPM2. Last update: 25th April, 2021, 7:45 AM
RFPM2 – current probe described a current probe for use with a power meter calibrated in dBm (eg RFPM1 and RFPM2). RFPM2 – current probe – #2 exposed some of the build details. This article reports the completed article. Above the current probe with RFPM2, the display does not show well at this camera angle… … Continue reading RFPM2 – current probe – #3
RFPM2 – current probe described a current probe for use with a power meter calibrated in dBm (eg RFPM1 and RFPM2). Progress has been slow (too many projects?), but the CNC Router project matures and it is time to try making some components of the current probe. The PCB was designed in Kicad. Electrically, the … Continue reading RFPM2 – current probe – #2
The RF Power Meter 2 (RFPM2) stores calibration constants in a file located in the (SPIFFS) file system in the microcontroller flash. The file opened by default when RFPM2 starts is /default.cfg, the following is an example. { “name”:”dBm”, “hostname”:”rfpm201″, “vref”:3.3, “avg”:3, “slope”:0.12991, “intercept”:-91.406, “unit”:”dBm”, “lcdfsd”:16 } The parameters above capture the most basic operation … Continue reading RFPM2 – calibration files
The RF Power Meter 2 (RFPM2) stores calibration constants in a file located in the (SPIFFS) file system in the microcontroller flash. The WiFi credentials are stored separately at the default location in the flash. Calibration constants The AD8307 outputs a voltage from zero to about 3V for inputs from around -90 to +15dBm. The … Continue reading RFPM2 – calibration
This article describes a current probe for use with a power meter calibrated in dBm (eg RFPM1 and RFPM2). For use with RFPM1 and RFPM2, both of which read to 16dBm max, it is convenient that the scaling factor for the probe is 0dBA/dBm, ie that those meters read dBA directly, implying a current range … Continue reading RFPM2 – current probe
The RF Power Meter 2 is a development based on the utility of RFPM1, but it shares nothing with the RFPM1, save using an AD8307 as the sense module. Design criteria The design criteria are: small, portable, battery powered; direct reading dB scale; flexibility for a range of adapters to measure power, current etc; local … Continue reading RF Power Meter 2 (RFPM2)