Thoughts on a Wideband SDR Recording Tool

As part of the HamSci Solar Eclipse experiment, I recorded wideband data from my SDRs on the theory that capturing the data for later study might be more productive (and less stressful) than trying to do measurements in real time. I think that theory played out very well. I used a simple Gnu Radio flowgraph to do the recording from an HPSDR Hermes receiver. When I say simple, I mean simple. Here’s the whole thing, which records four 384 kHz […]

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Pulse Per Second Dividers, Overdone

Several years ago I designed a little circuit board called the T2-Mini that provides life support for one of Tom Van Baak’s very wonderful picDIV PIC-based frequency dividers. The idea is to convert the 1, 2.5, 5, or 10 MHz output from a frequency standard to a one pulse-per-second (PPS) signal for use in frequency stability measurements. I don’t do things in a small way, so I built a rack enclosure (using the Front Panel Express service to hold 8 […]

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TICC Timestamping Counter

My latest project has turned out to be my most complex (so far…), involving both new-fangled hardware and quite a bit of software, but it’s now finished and working well. Meet the TICC, an Arduino Mega 2560 shield that implements a two channel timestamping counter that has resolution of better than 60 picoseconds (that’s 60 trillionths of a second). TAPR did a production run (we still have them available; go to and the units have been in peoples’ hands […]

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TADD-3 Enclosure

Just finished the second piece of my multiplexed measuring system. This one isn’t too sexy, but is a necessary part — a pulse-per-second (“PPS”) distribution system. This enclosure contains 4 TADD-3 PPS distribution boards. Each board has 2 sets of 3 outputs, plus 2 RS-232 level outputs. So, there are 8 input connectors on the rear, as well as 4 DE9 connectors (the PPS signal is on the DCD line, and I’m only bringing out the RS-232 signal from the […]

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TASS System Multi-board RF Performance

The TASS switch system made a design compromise that means its RF performance has some variation depending on which combination of ports is selected. When using a port that’s not at the far end of the board from the common, there is a transmission line stub of varying length that affects VHF performance. A single TASS board works well through 150 MHz. The question has been what happens when you build a multi-board system? Now that I have the TASS […]

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TASS System enclosure

Several of the design projects I’ve done for TAPR were part of a larger concept I’ve been working on for several years: a measurement system that will allow me to compare the pulse-per-second (PPS) outputs from a bunch of test devices against one of several reference clocks over long time periods (sometimes a year or more). A key part of that system is a “multiplexer” or switch matrix that allows selecting one of several devices under test (DUT) and reference […]

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An interface from Hermes/ANAN to the TASS relay board

I didn’t even think of it when I was designing the TASS-R relay switch system, but the relay board can be used with an HPSDR Hermes, ANAN-10, or ANAN-100/200 radio without requiring use of an Arduino or other controller.  These radios provide 7 open collector outputs that can be programmed from within the PowerSDR software.  A simple interface board allows the TASS-R to be controlled by these outputs. The idea is that two of the outputs can be used as […]

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TASS Switching System announced, and fun with enclosures

Today TAPR announced availability of a project I’ve been working on for a while, a computer-controlled switch system called the TASS.  It consists of an 8-port relay bank that handles from DC to 150 MHz, a shield for an Arduino, and open source software for the Arduino. You can order the boards from I also designed an enclosure for a TASS board plus touchscreen controller, and had that built by Front Panel Express.  Here are some pictures of the […]

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