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Weeknotes: Stabilizing the PicoW Autokeyer; Ionosonde Distance to a QSO Path; Starting Google Visualization Conversions

 The gang, (12 year-old Diaze aka KO6BTY, 11 year-old Mota, and 8 year-old Tawnse), and I did things with vector cross products, operated Raspberry Pis in the face of radio frequency interference (RFI) and started to update the ham radio exams Javascript charting package calls this week.

Ionosphere and Cross Products

KO6BTY and I put together kml files that show the approximated F2 skip of a QSO last year. The maps are very approximate because they only take the Pt Arguello ionosonde down the coast from us into consideration. To determine what other ionosondes to use data from, we needed to know how far each of the ionosondes was from the path between an arbitrary pair of QSO stations. In other words, we needed to work with spherical trigonometry. The first step was to figure out the algorithm. The solution was easy to find on StackOverflow, but it was hard to picture at first. I fixed that by getting back into using Sage for demos. The final step is shown below.


Raspberry PI RFI

KO6BTY and I built an auto-keyer for the her FT-840. It worked pretty well, but had RFI issues. Over the course of the week, we've isntalled a balun on her dipole, moved the keyer and the laptop that controls it, and shortened interconnect wires in the keyer. We're now able to key the transmitter on 10 meters at the rig's maximum power without the keyer rebooting.


Google Visualization Chart API Update

The chart API we've been using for the ham radio exams changed. More than a decade ago as it turns out. I'm working out how to assign the necessary updates as worksheet sort of assignments for the gang. This is a big experiment because I am mostly un-enamored of the whole worksheet model. The gang's schedule, and mine are getting too busy to easily support the talk-it-through while doing it model of unschooling learning that we've had really good success with until now though.


Coming up:

I'm starting to design a Datasette enabled version of the ham radio practice exams. It just makes sense. I used to widely distribute them as a Google App Engines deployment, but that's been a lot of work. Having something that's open-source and that just does the job for the gang and myself sounds pretty cush.


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