Electronics, Linux system development, Radio & antennas, Radioastronomy, Software

Satellite LNB controller with GUI interface

Satellite LNB are quite cheap and easy to get devices. There are different models for different bands (C, Ku, and Ka) with different characteristics like SNR, noise figure, etc. Typically those devices are used with TV Set-top boxes. More interesting is that LNB can be easily connected to an SDR receiver. LNB is a simple frequency down-converter with an output…

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Linux kernel, Software

Linux block device driver

My article about character devices is quite popular so I decided to write something about another big class of the devices in Linux – block devices. This type of device is used to access various types of storage hardware – hard disks, SSD, and so on. Here I want to describe blk-mq based devices in modern (>= 5.0) Linux kernels…

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Electronics, Radio & antennas

Cheap single-component RF filters

Low, Band, and High – pass filters are one of the major components when working with RF. Depending on the application, filters can reduce output noise and unwanted signals, or limit a transmit signal to a pre-specified frequency band in order to prevent interfering with other signals around. Here I want to describe how to build simple and cheap single-component…

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Linux kernel, Linux system development, Software

C++ in Linux kernel

Linux kernel is written in C (and in Assembly in platform-specific portions) language. C language is only one allowed language to write kernel modules. And there is no problem, in most of the cases. But sometimes some stranger things may be required. Let’s see how to use C++ for the Linux kernel modules.

Electronics, Networking, Software

RS-485 practice and theory

Just built two RS-485 adapters (version 2) and decided to write a little note about the RS-485 bus (and differential line) theory plus perform some testing of the devices. This material mostly interesting for newbies. At the end of this article, you can find a funny way to test these devices 🙂