[time-nuts] Thunderbolt, Rb, Scopes at SF Bay Maker Faire this weekend

Leigh L. Klotz, Jr. WA5ZNU Leigh at WA5ZNU.org
Mon May 24 23:10:41 UTC 2010

I received some messages asking how the demo went, so I'll summarize here.

If you weren't originally interested in this demo or its results, you
probably won't be interested in this.

On Friday, we showed the following demos to 3rd to 9th graders:
- paper-based oscilloscope
- disk-drive voice coil/laser/mirror scope
- signal generator and regular CRT scope
- Rb and Thunderbolt in two-channel and XY display
- Speed-of-sound measurement using two microphones and a digital Tek scope
- WiFi signals on a Tek spectrum analyzer

On Saturday and Sunday, we showed these same demos to a general audience,
and also added an old-style "Octopus" signal tracer made showing a 1N4001
diode curve.

There was a generally positive response to the graduated levels of
abstraction in the demos, and quite a few people said they'd finally
understood what an oscilloscope did, including some current scope owners. 
Just about everybody who got the advanced demo liked seeing the 1ppb
difference (~100s period for 10MHz) demo with the Rb and Thunderbolt.

The best part for me was when a former NIST researcher came by and
participated incognito. Judging by his reactions, I'd say I'd have gotten
about a B+ if I were being graded.  He made some good recommendations for
how to characterize and adjust my Rb based on a 12-hour comparison with
the Thunderbolt.


> As part of the SF Bay Area Maker Faire this weekend, I'll be showing a
> Thunderbolt GPSDO and a FE-5680A Rubidium disciplined oscillator, both
> connected to a $25 flea-market oscilloscope.
> The demo is part of a hands-on "things to do with oscilloscopes."  In this
> experiment, we'll have visitors use a stopwatch to measure how long it
> takes for a 360 degree phase change, and use that to calculate the
> fractional PPB difference between the two frequencies.
> We'll be at the ARRL booth, which is in the Fiesta Building, near the
> Tesla Stage entrance.
> http://www.makerfaire.com/
> Leigh/WA5ZNU
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