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https://github.com/mrRobot62/vtx_power_measure

Python script to read out an RC Immersion RF-Meter to measure VTX signal strength. Quick and dirty implementation, with storing data into an INFLUX DB
https://github.com/mrRobot62/vtx_power_measure

betaflight excel fpv frequencies grafana immersion-rf-meter influx influxdb influxdb2 measurment numbers python vtx

Last synced: 3 months ago
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Python script to read out an RC Immersion RF-Meter to measure VTX signal strength. Quick and dirty implementation, with storing data into an INFLUX DB

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README 

        
# VTX power measurment tool



Terminal based python script based on a pandas library. It can be used to read an Immersion RF-Meter v2 via USB.



This script is not finished at all and in an alpha-release status ;-). But it works for my needs.



## Note

This software is tested on OSX only and should be running on Linux as well. Working unter Windows is ongoing.



> This is a quick & dirty implementation to compare different VTX boards on my workbench - and what can I say - none of the cheap Banggood / AliExpress China VTX boards came close to the manufacturer's stated maximum output power. 
 Most 800mW VTX delivered on average between 500-650mw. I tested about 10-12 different VTX boards. 

**Buy cheap, buy twice**



**In comparision to a TBS-Sixty9 vtx no China crap comes into the range of TBS !**



# Immersion RF-Meter V2

https://www.immersionrc.com/fpv-products/rfpwrv2/



For this tool the Immersion RF-Meter V2 is used and connected via USB to the host.

This little RF-Meter use a simple CDC parameters for communication.



# Workflow

A couple of different parameters controll the worklow

* number of different frequencies

* number of different power (mW) 

* Parameters like "delay" or "time" are used to set number of readings per second and how long a measurment per frequence and per power takes



System read the first frequency and the first power configuration and wait for user to configure connected vtx-board. If done press **ENTER**.



## Example terminal output

````

***************************************************************************

Please set POWER on     VTX to 200mW

Please set FREQ on      VTX to 5785Mhz Freq



Nearest frequency for ImmersionRF-Meter was set to 5800Mhz automatically



Please set your VTX to above values - Press ENTER to start measuring

***************************************************************************

````



Now the system measures `"time"` seconds and collect data. In this case loop through all power configurations. If done, loop through all frequencies



# Stored data

| Attribute | csv | InfluxDB | Comment |

|:---|:--:|:--:|:---|

| Model | x | x | Model/Type of VTX board |

| Test | x | x | InfluxDB tag: unique timestamp for the complete run |

| Band | x | x | InfluxDB tag: VTX Band (like A, B, H, I, R, ...) |

| Info | x |  | only output to CSV, additional information pased on paramter --info |

| t_mw | x | x | InfluxDB tag: target mw (e.g. 25mW, 100mW, 200mW, ...) |

| t_dbm | x | x | InfluxDB tag: target mBm (e.g. 14.0 dBm, ...) |

| mw | x | x | InfluxDB field key = mW, field value = measured mw |

| dbm | x | x | InfluxDB field key = dbm, field value = calculated from read mW |

| diff_mw | x | x | InfluxDB field key = diff_mw, field value = target_mW - mW |

| diff_dbm | x | x | InfluxDB field key = diff_dbm, field value = target_dbm - dbm |

| timestamp |  | x | InfluxDB timestamp unix format in nanoseconds (ns) |



# Starting parameters

This python script do not have any graphical output, it's designed as a pure terminal script with output on console.



## Arguments



  

## Examples



  



# InfluxDB & Grafana

It's possible to store data into a InfluxDB V2 database. Generating output plots can be done with grafana.



A simple dashboard is included in folder



Via parameter it's possible to include output to this database



# CSV output

Via parameter it's possible to create from all data an output csv file.

Filename includes model name and a timestamp.

Default separator is `";"` - can be adjusted inside `config.py`



# Used Libraries

* Pandas

* InfluxDBClient

* Matplotlib

* FPDF



# Developer hints



  



# History

|Version|Date|Info|

|:---|:---|:---|

|0.1|06-21|initial|