My first slide rule

I grew up with electronic calculators and while I remember my uncle having a slide rule that I played with as a kid (didn’t know what it was at the time…it was just a neat looking thing with slide-y bits and numbers printed on it), I never used one until I got my first one in high school.

At the end of one of my high school math classes, I noticed the teacher using something that wasn’t a calculator to work out the grades on a test we just had. Intrigued, I went over and asked about it. He was using a slide rule, showed me some basic operations on it. He was calculating percentages faster on his slide rule than using a calculator. I thought it was just the neatest thing in the world. He reached into one of his desk drawers, pulled out a box, and handed it to me.

I had my first slide rule!

Ricoh No. 102 slide rule case
Ricoh No. 102 slide rule case
Ricoh No. 102 slide rule
Ricoh No. 102 slide rule

It’s a pretty simple beginner’s slide rule made of bamboo with a plastic reticle. It’s a single sided slide rule with a reversible slider. that has B/CI/C scales on one side and S/L/T scales on the other. Seems like this model would have been an inexpensive slide rule targeted at the student market.

The back side has some handy reference tables and formulas.

I taught myself how to use a slide rule and used it pretty regularly through my last year of high school and into my first couple years of undergrad. The main reason I stopped using it was that most of the problems became more symbolic, and the numeric problems I did get became complex enough that it was faster for me to use my calculator (HP-28S at the time). The slide rule stayed in the desk drawer for the rest of my undergrad and grad school.

Most of my calculations are done using spreadsheets now, but I pull the slide rule out every now and then for some quick calculations and to remind myself how to use it.

Slide rules

Acquired some slide rules this week (that makes three that I have now, so I think that qualifies as a collection). The new additions came from the estate of N6GA (SK) and were posted on one the amateur radio mailing lists I subscribe to. Both came in hard cases and are in pretty good condition.

Slide rules
Keuffel & Esser (K&E) 4080-3 log-log slide rule (top) and Pickett N-515-T Cleveland Institute of Electronics electronics slide rule (bottom)

The Keuffel & Esser 4080-3 slide rule has a serial number of 939707 (some nice symmetry in that number). Looks like this is a 1939 version, based on the scales on the rule and this catalog page.

The plastic brace parts of the reticle are broken, and there’s some corrosion on the metal frame. Think it might be possible to fashion some replacement braces out of bamboo or something similar. Looks like I might be able to purchase a used one too. No manual for this one, so I’ll have to see if I can hunt one down.

The other slide rule is a Pickett N-515-T. Seems like this particular model was made by Pickett for the Cleveland Institute of Electronics. Has some scales specifically for electronics related calculations and handy electronics formulas printed on the back. Not quite as chunky as the K&E slide rule, but it’s made of metal (aluminum I think) so it’s pretty rugged. No manual with this one either, but I was able to find some Cleveland Institute of Electronics slide rule course booklets online.

Will be fun learning how to use these slide rules.

Mah gimpy foot

I’ve been limping around on a messed up right foot for the past week since Field Day. Although the foot has gotten a little better since last week, it’s still somewhat painful to walk on and there’s still a bit of swelling going on (enough that my foot doesn’t fit into my shoe very well anymore).

Made an appointment to see the doctor, and got some x-rays on my foot. Good news is that according to the radiology report, there are no fractures and no bones out of place. Just some soft tissue swelling.

Got a referral to orthopedics so in the meantime, rest, hot/cold compresses for the swelling, and ibuprofen for the pain as needed.

Southeast Linuxfest 2019

This year’s Southeast Linuxfest was another great event. Came back with many photos that will probably take me a while to get around to going through before I can post them.

Crowds seemed a little bit smaller this year, but we had the whole hotel meeting space this year which spread the crowd out a fair bit so that probably altered my perception of this year’s crowd size.

Although I spent most of my time going around taking photos, I did manage to sit in on a few interesting talks. SELF network guy Zack Underwood gave a good talk on his adventure in building a tiny house. The “Go Forth And Brown Bag” session by Sarah Ofsdahl (one of the last talks of SELF) was another good one with some good tips for what to put into training sessions and how to do them. Steve Owens’ “Getting Kids Involved In Computing” talk was also a good one too, highlighting a number of kid-friendly resources to help kids learn how to program.

Fiber track was pretty popular again this year, and they also sponsored a movie night where Plan 9 From Outer Space with the Rifftrax commentary was shown. I missed the movie because I was busy with the amateur radio testing session and GPG key signing party.

SELF amateur radio boosted its presence a bit this year with a special event station, W4L (Whiskey 4 Linux) that ran during the day for most of the weekend. The hotel gave the group permission to set up an antenna on the roof of the conference center, so a 30′ mast with a G5RV dipole was put up. Not sure how many contacts they ended up making, but sounded like they were doing reasonably well.

There was also the usual amateur radio license test session held at SELF this year, with 20 people taking the test. Not sure of the exact numbers, but most of them left with either a new license or upgrade. One person with an expired Technician class license came to the test and left with a General class license.

This year’s SELF keynote was given by Eric S Raymond (who I only recently learned is a somewhat controversial figure) which was given remotely due to recent medical issues. ESR talked about the “Load Bearing Internet People” (LBIP) problem, those people who are developing/maintaining critical pieces of software that keep what we know as “The Internet” running, but receive little to no support for doing so. Although there were a few problems with the remote presentation (video froze up, but audio still came through), I thought it was a pretty good talk he gave. Regardless of how you feel about ESR, it’s an important issue that he brought up.

The SELF Craft Beer Exchange happened again this year. Got to sample some pretty tasty beers. There was A LOT OF BEER, but not enough people drinking it this year because after Friday’s party it looked like barely a dent had been made in what was brought. Even after Saturday’s party, it looked like hardly any was gone.

I ended up leaving with almost twice as much beer as I brought to share.

1. Bring beer to share
2. ???
3. Profit!

I ended up grabbing a few more beers after I tweeted this, just because there was still so much left over.

This year, the #SELF2019 hash tag collision on Twitter turned out to be especially entertaining with Southeast Leatherfest happening the same weekend. Both events usually happen about the same time each year.

The call for presenters for SELF 2020 is already open. Go submit something!