Receiving and analyzing radio signals is fun. Receiving satellite signal is even better. A few years ago, I had a nice 3m satellite dish with a hydrogen line receiver. Now I have only a small balcony with limited antennas placement ability. I decided to build a custom 40 cm dish with a servo-based rotator. Sure, it’s impossible to receive weak…
Author: Oleg Kutkov
Compact and powerful DC driver using IRS2104
A few years ago, I wrote about the powerful DC motor driver based on IR2110. This construction appeared to be quite popular. This time I want to describe a much compact and simpler (but still very powerful) solution with IRS2104. This device can be used to control any power-hungry DC load like DC motors, heaters, and so on.
Writing a PCI device driver for Linux
In this article, I want to discuss some basics of the Linux PCI/PCIe drivers development. I think this issue is not properly covered, and some existing information is might be outdated. I will show basic concepts and important structures, and this is might be a good beginner guide for newbie driver developers.
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…
Mysterious Flat satellite antenna from China
A few months ago, I found a quite unusual satellite antenna on the well-known Chinese portal. The antenna was relatively small, completely flat, and declared as a Ku-band satellite TV antenna. I was really wondered what’s inside and how it works so I decided to buy one sample.
Reworking linear polarization satellite LNB into a circular polarized
In this article, I want to discuss different types of satellite LNB, polarization, and depolarization of waves. Also, I’ll show how to rework the LNB. Also, we will discuss a theory to figure out why this rework is working. The primary topic here is Ku-band LNB, but all this also works for the Ka-band and C-band.
Combining two HackRF SDR to see more
HackRF One is a popular SDR transceiver and a really nice piece of hardware. For a reasonable price, you can get fully open hardware to monitor radio signals in a wide range (20MHz – 6GHz, but really up to 7GHz). Boards support external clocking and can be easily customized. I believe there is only one concern about this board is…
Linux block device driver
My article about character devices is quite popular, so I decided to write something about another big class of devices in Linux – block devices. This type of device is used to access various storage hardware types – hard disks, SSD, etc. Here I want to describe blk-mq based devices in modern (>= 5.0) Linux kernels and a previous type…
Cheap single-component RF filters
Low, Band, and High – pass filters are 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 to prevent interference with other signals. Here I want to describe how to build simple and cheap single-component (ceramic) filters for your DIY projects.
C++ in Linux kernel
Linux kernel is written in C (and in Assembly in platform-specific portions) language. C language is the only language allowed to write kernel modules. And there is no problem in most cases. But sometimes, some stranger things may be required. Let’s see how to use C++ for the Linux kernel modules.