The info in this and in part 4 was aided tremendously by several folks on the “op25-dev” mailing list. Without their help, I would not have even known where to start in getting my system running. I hope that what I’m documenting here will be helpful for others going down
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Here’s how to install the OP25 scanning software. If you don’t already have Gnuradio installed on a Linux system, do those two things first.
Any current Linux distribution works. I use Linux Mint which is very similar to Ubuntu.
The easiest way to install Gnuradio is to use a script
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A couple of weeks ago at the Dayton Hamvention I bought a fancy Whistler TRX2 scanner that can receive the new P25 digital trunking system that’s been rolled-out statewide here in Ohio. Unfortunately, after a lot of attempts, I still can’t get it to reliably receive the talkgroups I’m most
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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
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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
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My FTS-1050A OCXO has thumbwheels to set the EFC, which makes it convenient to use this frequency standard to generate slightly offset frequencies. I measured the frequency with various EFC settings (compared to an HP 5061B-004 Cesium) and these plots show the results for future reference.
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
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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
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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
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I rediscovered a post from Corby Dawson with pinouts for the DB9 connector on the above OCXO and wanted to preserve the info here. Thanks, Corby!
1000B 1000A-100 1200 and 9110
1 EFC ground EFC ground EFC ground
2 EFC +- 10V EFC +- 10V EFC 0 to +10V
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