Category: Miscellaneous babble

Hit 100 000 miles on the car today.

The car started off at just over 40 000 miles when we bought it about 3.5 years ago to replace the Camry.

Whee.

A Reddit post in r/Charleston led me to this cool online collection of pre-1945 USGS topographical maps at the University of Texas Libraries.

I love looking at old maps and seeing what areas used to look like and comparing them to modern maps to see how things have changed. The South Carolina collection has pretty good coverage of the Charleston area so I downloaded a few and went browsing around.

Here’s what the area just north of modern day Goose Creek looked like in 1919 (from the Summerville quadrangle map). Some of the roads in the 1919 map are still around, as is the rail line labeled Atlantic Coast.

Here’s is a screenshot from Google Maps of the same area. Visible just below and right of center is the Google Data Center. You can also see the outlines of the swampy areas on the 1919 map are prominently visible.

Maps can be so much fun.

Sending my name off to Mars again, this time withe the Mars 2020 Rover.

Send your name!

One of the exposure meters in my collection (a Radcal/MDH 1515) uses this Eveready #493 300V battery as bias voltage source for the ionization chamber used to measure x-ray exposure. The rest of the meter is powered by 4x2V rechargable lead acid batteries in a D cell form factor.

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Looks like this battery was installed in December 2002. Last calibration date for the meter was 2003, so it was probably replaced when it was sent in for the previous calibration.

After 16 years of sitting on the shelf, the battery is pretty flat.

Let’s take the cardboard off and have a look at what’s inside.

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There are 10 plastic wrapped packs, each 1.3 cm x 2.2 cm x 6.6 cm long, all connected in series. Each pack appears to have 20 individual cells coated in a waxy type material and wrapped in plastic to hold them all together. With 200 cells, that gives 1.5 V for each cell.

Looks like there’s been a bit of leakage while the battery sat on the shelf for the past 16 years.

A close up of one of the packs.

Neat stuff.

In addition to the audio amp find, I also managed to catch an EICO 1030 regulated power supply being wheeled out to be put on the shelf. Naturally, I had to add that to my cart as well.

I’m starting to accumulate a bit of a power supply collection now, it seems.

Haven’t looked inside it yet, but I did plug it in and turn it on. Made the satisfying “thunk” of a big linear transformer being energized, and the 6.3 VAC terminals were putting out about 6.5 VAC (unloaded), which seemed reasonable.

A quick look around the Internets yields hits on various audio forms, so seems like a popular piece of gear in those circles.

While I was scoping out the electronics, Connie was over in the books and found a copy of Practical Antenna Handbook by Joseph Carr, so that went into the cart as well. No such thing as too many antenna books, right?

Good shopping day at the thrift store today.