Well, it’s Friday the 13th. We just had a Friday the 13th just 13 weeks ago, and we will have another one in 13 weeks. Wow! That’s almost spooky!
Friday really was Friday the 13th for me and my co-workers. We had several network problems, one which required me to run from one building to another, holding my umbrella tightly to keep it from blowing away as the rain came down heavily. Pants got wet from the knees down. 
The rain storm passed through quickly so everything was calm by the end of the day. 
No noticeable thunder, lightning or hail, though.
Vintage HP Test Equipment When I was a teenager a neighbor kid and I would hang out at the shop in the garage of a neighbor who was a ham. He had a lot of HP test equipment and the usual TEK and other high quality stuff, like General Radio gear. We got to use it if we helped him get a few other things done. We also got to take a ride in his private airplane, and ride to the airport in his Porsche. 🙂
On occasion he would get old test equipment to play with, usually on the condition that it got repaired, or at least troubleshot to find out what was wrong. Some of it was very good quality for its day, just that it had long been superceded by newer versions. An example is this ancient HP 521A frequency counter, which used neon lights in a long column with a mask in front with the digits etched into it. Hey, nothing wrong with that; it was a lot easier to read than a binary display! 0000, 0001, 0010, etc. There is much more of the same, including manuals in www.HPArchive.com
The ‘wiggle stick’ meters were Simpson, Triplett, Weston, and of course HP. The John Fluke Company started making high quality test equipment, one of which was the differential voltmeter. This is a later version; the earlier ones were bigger and heavier. Basically the operator was doing manually what is automatically done today. But you could get accuracy in the millivolts, something you couldn’t do with a regular wiggle stick meter.
One type of test equipment that he had was General Radio gear. This was top of the line for its day, much of the accuracy was due to accuracy in construction and quality in workmanship. One innovative piece of General Radio gear was the GR 874 connector. It was hermaphrodite; any connector would fit any other connector. How? Well, take a look.
Back then the RF equipment for UHF and above was marked KMC/s (kilomegacycles per second) because Hertz and Giga- had not yet been adopted as a standard. See this NIST page for more info.
Quantsuff sent me a link to a Youtube video of a very large digital display cranking away. Very innovative. They will never have a shortage of coffee mug holders!
Back to experimenting…