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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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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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 🙂


Isolated USB to RS485 adapter version 2

This is a second version of the USB to RS485 adapter. Please read this article about the first version. The new device is built with ISO3082 and requires fewer components. Also, this device can provide more reliability in some situations.

Astro tools, Electronics, Radio & antennas

Low noise and low cost amplifier for radio astronomy, 21 cm band

21 cm band also known as the Hydrogen line is one of the important bands in radio astronomy. Please read this Wikipedia article if you not familiar with the Hydrogen line. Nowadays even radio amateurs can observe this signal from outer space, thanks to modern hardware. One of the most important parts of any receiver is the antenna and input…

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