My house has 2 CenturyLink fiber optic connections to The Internet. On July 5, 2025, the connections didn’t work for 3 periods of time.

I made two NTP servers using Raspberry Pi single-board computers and GPS receivers.

The resulting NTP servers seem to work well.

Second quarter calendar 2025 lottery winnings summary!

$75 dollar expenditure, $8 winnings!

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My OpenWrt One router had a problem, which looked analogous to a disk failure. It went into a reboot loop.

A couple of years ago, I made an attempt to create a NTP server using a GPS receiver. I failed.

I tried again in 2025, this time I succeeded.

In January 2025, I started monitoring my network with Smokeping.

I had previously noticed increased latency when a Velop router was connected via powerline ethernet. After upgrading it to OpenWrt, I put that particular Velop back on my network via a $20 TP-Link 8 port 1GbE router. I saw a much smaller increase in latency using the router versus a direct cabled connection.

Here’s a 70 year old paper that’s worth a closer look:

Leo A. Goodman (1954) Some Practical Techniques in Serial Number Analysis, Journal of the American Statistical Association, 49:265, 97-112

This is the only instructions/safety info in a package of 3, 5 mW, laser pointers:

I looked around and found some papers related to Ruggles and Brodie’s 1947 Economic Intelligence paper.