Categories
Hardware

Hello Chromebook (Again, again!)

I bought my first Chromebook back in 2014, and have been using it daily up until a year or so ago when it stopped receiving security updates. I’ve used it occasionally since but have always a bit wary of doing anything important on it.

So, I decided to upgrade it. This time, I found a Lenovo Ideapad 3 for £97.49 from Argos. The official spec is:

  • Intel N4020 at 1.1 GHz
  • 4GB RAM
  • 64 GB eMMC
  • microSD card slot
  • 11.6 inch screen

Physically it’s very similar in size to the Chromebook it replaces. It’s so much more useful though. As well as an up to date version of ChromeOS (with updates guaranteed to the middle of 2027), it also is able to run Android apps which means I have access to lots of additional software my old Chromebook didn’t have.

The real icing on the cake for me is the support for Linux. In just a few mouse-clicks, I had installed Debian Buster inside a container. This works really well and gives me scope to install all of the usual Linux software that I like. I’ve added the Signal messaging app (which otherwise would be unavailable on a Chromebook) and the integration with ChromeOS is great. Signal appears in the applications menu, and if I launch it, ChromeOS silently brings up the container (if it’s not already running) and then launches Signal seamlessly. Lovely.

Categories
Amateur Radio Hardware

SDR Trouble

One of my colleagues asked me to have a look at receiver that wasn’t behaving well. It was one of the many USB receivers that are around based on the RTL 2832U and Rafael Micro R820T tuner chips. The device was very intermittent, but he wasn’t sure if it was a problem with the hardware, or with the software (and drivers) on his Windows PC. I don’t run Windows myself, so would be able to easily rule that out as a potential problem.

On connecting the device up to my Linux machine, it appeared to be behaving itself and showed up listed as a DVB-T device when I typed ‘lsusb’ into my terminal. However, when trying to actually use the device, it returned lots of errors before disappearing from the USB bus. Re-plugging it would make it come back to life again.

In my experience, complex microprocessor based things generally either work or they don’t. So to see a device that would speak happily over USB but fall over when used was a bit odd. What might cause something to misbehave in this way?

Thankfully my first hunch was correct. I swapped the rather long and thin USB cable for a short fat one. Hey presto – the device behaved perfectly and I left it running for a few hours without any issues. The resistance in the original cable, combined with the high current draw by the receiver was causing the voltages to drop, interfering with the normal operation of the device.

So, it’s always worth trying different cables when troubleshooting something, even if (as in this case) the original cable appears to be doing its job.