Radiosonde Auto-RX 1.7.2 – current consumption capture

Radiosonde Auto-RX 1.7.2 is a software package for downloading data from a weather balloon.

Above is a screenshot from Radiosonde Auto-RX 1.7.2. 

A friend has experienced problems where his RTL-SDR dongle stops working periodically. This is apparently a known problem if the power supply voltage is low.

This article documents current and voltage at the USB power jack on the RPi of:

  • RPi 3B+ running Radiosonde Auto-RX 1.7.2;
  • RTL-SDR v3 dongle on a 200mm USB extension cable; and
  • ‘official’ RPi 3+ (5.1V 2.5A) power supply.

The RPi3B+ is a problem, it spews log messages when the supply falls much below 5V, and IIRC even if the voltage is withing the USB standards. That said, my understanding is that in this scenario, it is the RTL-SDR that may be the intolerant one.

Above is a capture of voltage and current when the system is in the scanning mode. Periodically it launches a scan which drives system current up which causes a small sag in voltage.

Above is a scan when a balloon is being decoded, quite a different current profile.

Note that the measurements relate to the hardware configuration described, and to some extent the software build on the RPi.