More Solar Eclipse Analysis (HF Propagation)

I’ve continued processing the data generated from software-defined-radio recordings I made during the 2017 solar eclipse at my fairly isolated and low-RF-noise location on Beaver Island, Michigan (45 38 38 N, 85 29 24 W, grid square EN75gp). The nearest AM station is about 28 miles away, so it’s a pretty good site for monitoring the high frequency bands. The data was recorded over the eight hours from 1400 – 2200 UTC (10AM to 6PM EDT) on Monday, August 21, […]

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First data from Solar Eclipse 2017

I set up a smaller version of my mad-scientist stuff at our cottage on Beaver Island, Michigan (45 38 38 N, 85 29 24 W, grid square EN75gp), to record the RF spectrum before, during, and after the eclipse on August 21, 2017. The recordings were successful, and I captured just under 1 TB (!) of data. Fortunately, disk drives are cheap these days. I’ve done the very first step of analysis on one of the data sets — a […]

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FTS-4100 Cesium Standard tests

It wasn’t too hard for the HamSci guys to convince me to bring a Cesium frequency standard to my portable location in Michigan to drive the HPSDR receiver that will do band recordings for the 2017 Total Solar Eclipse HF Wideband Recording Experiment. I had been planning to use a GPSDO, but that would be too simple. My “sort-of-portable” Cesium is an old FTS-4100 that came out of military service. It was designed for shipboard use (I think as part […]

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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 http://tapr.org/kits_ticc.html) and the units have been in peoples’ hands […]

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FTS-1050A EFC Settings

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.

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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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Pinouts for FTS 1200 9110 1000A-100 1000B OXCO

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 3 coarse wiper NC NC 4 +12 pot ref. (10K) NC NC 5 Ground Ground Ground 6 oven mon. oven mon. oven mon. 7 +28V oven +18V oven NC 8 +28V […]

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