Electronics, Radio & antennas

1PPS distribution circuit

1PPS is a great way to synchronize multiple devices and measure time intervals. A typical source of the 1PPS is a GPS receiver. This clock is disciplined by GPS atomic clock and has a reasonable precision. GPS receiver 1PPS output should have enough loading capability, but it’s a good idea to use a buffer. Especially when voltage level translation is…

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Electronics

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.

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 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.

Electronics, Networking, Software

RS-485 practice and theory

I 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 🙂