Quiet day today
Got the bins filled up with firewood -- first snow of the season resting lightly on the hills.
Spending today building a power supply for a
Trimble Thunderbolt GPS and getting it running with
Lady Heather. Picked it up for $40 on eBay. The Thunderbolt was originally used at a cell phone tower to synchronize it with neighboring towers. Very clever idea actually, GPS satellites have very accurate clocks on them (timing is the way that we derive position) but you don't always see enough satellites to get a precise time. The Thunderbolt has a very accurate quartz clock inside a temperature-controlled oven so it has a very stable frequency. When the Thunderbolt is able to get an accurate time, it "disciplines" the local oscillator -- adjusting it to match the correct frequency. Lady Heather is the software that handles the discipline (the logo is the silhouette of a woman holding a whip).
The upshot is that my little ham shack will have cesium-clock accurate timekeeping for well under $100
Fun stuff...
Posted by DaveH at October 20, 2012 2:59 PM