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British Forum => Technical Support => Topic started by: davidbu99 on July 27, 2019, 12:27:41 pm

Title: Frequency Warning under hot weather conditions
Post by: davidbu99 on July 27, 2019, 12:27:41 pm

Can anyone explain the significance of the Frequency=Warning status and also the two temperature indications? (See attached)

I've a good quality Anker power supply and cable and recently swapped with a Pi 3B+. Fitted with a single RTL-SDR (low power unit). I get no warnings in my home testing up to about 60 degrees. This was a very hot day (which day hasn't been!).

I flew two segments and although the Frequency=Warning was displayed most of the time I can't say I experienced any issues with use (connected to SKD). Just want to check the meaning of the warning and whether this is just temperature related.

Title: Re: Frequency Warning under hot weather conditions
Post by: JCurtis on July 27, 2019, 01:00:02 pm

Lee will confirm but I suspect the Raspberry Pi reduced its clock speed to keep the temperature down.

Title: Re: Frequency Warning under hot weather conditions
Post by: davidbu99 on July 27, 2019, 06:00:42 pm

This Raspberry Pi documentation may answer my own question! For the 3B+ it suggests a soft limit of 60 degrees at which it starts lowering the frequency and a hard upper limit of 85 degrees. I saw a maximum of 83 degrees that day so suggests that frequency throttling helps lower the core temperature. That said Throttling = OK is also shown.

https://www.raspberrypi.org/documentation/hardware/raspberrypi/frequency-management.md