The so-called “infinite impedance detector” is a circuit that was commonly used in the old days of vacuum tubes. Since vacuum tubes can be somewhat considered to be heated JFETs, it is evident that such a circuit can also be built using a more modern, silicon-based approach. This article covers my first experiments with a […]
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Radio Frequency (RF)
Generate a stereo-FM multiplex waveform with Python and AWG
Generating more complex arbitrary waveform files for modern test equipment doesn’t have to be difficult. For a recent project, I needed a stereo-FM multiplex (MPX) signal containing two different tones in the left and right stereo audio channels. This article is going to show how to generate such a MPX signal for Siglent SGD-series arbitrary […]
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SITOR-B / NAVTEX Test Signal Generation
This article shows how to generate valid NAVTEX message bitstream using an Arduino. The Arduino implements proper CCIR476 character encoding, SITOR-B forward error correction, synchronization and phasing signals. An entry-level function generator is then used as a FSK modulator on 518 kHz where it can be received by a NAVTEX receiver. UPDATE: There also is […]
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VHF LDMOS Power Amplifier Experiments
The NXP MRF101 series high ruggedness N-channel Enhancement-mode lateral MOSFETs promise over 100 Watt CW output power and slightly over 20 dB gain from 1.8 MHz all the way up to 250 MHz. Their mismatch insensitivity for a VSWR of greater than 65:1 without significant device degradation makes these devices extremely interesting for amateur radio […]
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ICS501 / ICS501 VHF Experiments
The ICS501 / ICS511 from Renesas are easy to use, fully integrated clock multipliers for output frequencies up to 200 MHz. What makes them particuarly interesting is the integrated crystal oscillator circuit and ability to produce some fractional multiples, such as 6.25 or 2.5. So let’s find out if they’re interesting for the hobbyist who […]
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Automated Forward Gain Measurement
This article is going to take you into the world of automation. Using MATLAB and commercial off-the-shelf bits and pieces, this article will show how to measure the forward gain of a RF device. For a long time now I had a bunch of Mini Circuits portable test equipment bits and pieces sitting around. S […]
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Secondary Surveillance Radar | An Introduction
Quick introduction to Secondary Surveillance Radar and how it works. After explaining the absolute basics, I am showing how one can simulate transponder responses using off-the-shelf test equipment. RTL1090 is used to verify the generated signals as valid. If you want the arb waveform file for the 7777 Mode A response, here it is: https://baltic-lab.com/wp-content/uploads/2015/12/SQUAWK_7777_IDENT.zip
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What is a Gunnplexer? | Police Radar Gun
This video shows a couple of 10 GHz and 24 GHz gunnplexer, briefly explains what they do and shows how they can be used to determine an object’s speed.
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14 GHz Ku Band Block UpConverter
A quick look at what it takes to make a Block UpConverter (BUC) for the 14 GHz Ku-Band satellite uplink band work. A BUC is used in professional Broadcast TV environments to convert a video signal from a L-Band intermediate frequency to the 14 GHz range to be received by broadcast satellites.
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Instrument Landing System Testing
This video shows how easy it is to test an Instrument Landing System, ILS for short, receiver for localizer and glideslope accuracy. This video was shot in DNxHD using the Blackmagic HyperDeck shuttle I showed in another video (https://www.youtube.com/watch?v=cc83-Cc-vtw). After editing in Adobe Premiere and finishing it off in SpeedGrade, I exported it to h.264 […]
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