DIY: Adjustable 30 kV High Voltage Power Supply

High voltage power supplies can open interesting doors to research topics such as laser, x-ray, spark gap transmitters. And many other specialized niches. Unfortunately, laboratory grade high voltage power supplies are rather costly. Luckily, there is a much less expensive way to put high voltage experiments into the hobbyists reach. This article shows how to […]
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Diplexer with integrated Bias-T (Triplexer) for QO-100 and X-band microwave reception using LNBs

This article shows how to build a simple Triplexer (Diplexer plus integrated DC Bias-T) for use with commercial TV LNBs for QO-100 or X-band microwave experiments. Introduction When using modified, commercial LNBs for reception of the QO-100 amateur radio satellite or X-band microwave experiments, it is necessary to pass a clock-reference signal, a DC supply […]
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Tremolo DSP Effect for Arduino

This article continues my newly acquired interest in implementing digital signal processing algorithms on the Arduino GIGA R1 by showing how to implement a tremolo effect algorithm in software. After showing how to implement an Audio Loopback Device and a DSP Diode Clipping Algorithm for Overdrive and Distortion Effects on the Arduino GIGA R1 WiFi, […]
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DSP Diode Clipping Algorithm for Overdrive and Distortion Effects

This article shows how to approximate the behaviour of a regular diode in a mathematical equation and how to subsequently implement the behaviour in software. The DSP algorithm can be modified to implement different topologies, such as single diode clipping, dual diode symmetrical soft clipping or asymmetrical clipping. The easiest way to implement distortion through […]
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Critical length of a PCB trace and when to treat it as a transmission line

Ideally, the impedance of PCB traces should be matched to the load and source impedances. This becomes especially important in high-frequency and high-speed digital PCB designs. Various rules of thumb are available to determine the critical length at which a PCB trace should be treated as a transmission line. Below this critical length, an impedance […]
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Etching PCBs using hydrochloric acid and hydrogen peroxide

Choosing the right etchant for home made PCBs could be a science on its own. Some people prefer ferric chloride, some advocate for sodium persulfate and I personally prefer hydrochloric acid and hydrogen peroxide. This article shows how to use a mixture of hydrochloric acid and hydrogen peroxide in a safe and controllable manner. UPDATE: […]
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Universal Clock Translator using Renesas VersaClock 6E Devices

Due to the popularity of the QO-100 geostationary amateur radio communication satellite, precision GPS reference frequency sources (GPSDO) are becoming more and more common in home labs. The desire to derive different, fixed frequency signals from a GPSDO has similarly been increasing as different devices requiere different reference clocks with different frequencies. Therefore, this article […]
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LNB Modification for 10 GHz QO-100 Satellite Reception

This article shows how to modify an inexpensive LNB to accept an external LO-reference signal in order to be used as a K-band downconverter for QO-100 (Qatar Es’hail 2) amateur radio sattelite reception, radio astronomy or similar K-band experiments. This article is a shortened version of a scientific paper that I wrote as the lead […]
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Program uBlox GPS-module timepulse frequency (dynamically) with an Arduino

The uBlox GPS-modules are capable of providing various reference clock signals through the TIMEPULSE pin. By default, this pin outputs a 1 pulse-per-second (PPS) signal. For an upcoming project, a GPS disciplined oscillator (GPSDO), this output had to be adjusted to 100 kHz. Instead of using the manufactuer’s software, u-center, this task is supposed to […]
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