darkness

Had to stop by work on the way home from the S.O.’s this morning: a customer web server crashed last night, and it’s not in the rack so I couldn’t MasterSwitch it. Incidentally, this is the machine I recently installed Oracle on. It’s Red Hat 7.2 if memory serves. It complained by hitting max files open, I think, while running updatedb. I get the feeling it never recovered after that. It wouldn’t allow logins because I don’t think it could spare an FD to open the PAM libraries. I’m not quite sure why something didn’t exit (like updatedb) and free up some files. Makes me wonder if increasing the max number of open files on the system (I think I can do that) will help, or if that would just mean it’d take longer for the runaway process to eat up all FD’s on the system.

Then I was off to Harris Teeter, a local grocery store chain. I needed a can for my Cantenna. Snag: didn’t have a ruler. Instead I took the bottom of a piece of paper, which had a known size of 8.5″. Then I halved it, and halved it again, so I could get 4.25″ and 2.125″. I also took the bottom of a 5″ piece of paper and used that to mark 0.75″ off the end of the 4.25″ fold of the first sheet of paper. That should have given me a nice way to measure 3.5″. I also used the Cantenna how-to to calculate the 3/4 Guide Wavelength for diameters of between 3″ and 4″ in 0.25″ increments and wrote down those lengths.

When I got to the store, I couldn’t find any suitable cans. I checked soups, vegetables, weird canned items. Finally I found some canned ravioli from Chef Boy-ar-dee. I wouldn’t eat the shit to save my life (plus it had “beef” in it) but it seemed to be 4″ in diameter and was the tallest can I had found. If memory serves, the can was 5.5″ high, and the 3/4 Guide Wavelength for a diameter of 4″ is 5.15″. Feeling good I checked out with the Chef and headed home.

Once I got home… I still didn’t have a ruler. I found that darkho’s key chain had a mini-Leatherman on it, and that had a ruler along the back of it. It was awkward, but I got about the same measurements. (There was actually a lot more “oh, wait, no, I think I was way off measuring” and then “oh, no, I was right the first time” in between, but I’m trying to skip that.) Then I plugged 4″ in to the Cantenna how-to just to revisit the numbers, and I realized the TM01 cut-off frequency was too low at 4″ in diameter. Doh! I forgot to look at that number when I was transcribing the lengths onto the piece of paper I was using. Now I had to voyage out again.

In between here I’ll slip in that I got my car worked on. Something like $218. They said my brakes were fine (I thought they weren’t – must just be my driving) but I needed a new “Serpentine belt” and a coolant flush. Whatever. Let me pay my blood money and keep my free car running, please.

Anyway, now to Lowe’s, because I need screws for my N connectors. Oh, did I forget to mention that FA&B got my connectors out to me in record time? The box said three day, but I think it was at most two days, and quite possible one day. From FL to NC, sure, but still impressive. I like those guys, I think. Anyway, the Cantenna how-to says he used “#6×1/4″ stainless” nuts and bolts. After walking around Lowe’s screw aisle for a long time I found some #6 machine screws at 1/2″ in a pack of 50 or 100 or something obscene. I looked at them, I looked at the hole in the connector in my pocket… it didn’t quite seem right. So doing my best secret agent impression, I slipped a screw out of the box and tried to fit it in the connector. (My whole time at Lowe’s was spent half looking out of my eye anyway, since I kept pulling this tiny metallic thing out of my pocket (the connector) and putting it back again and again. I kept waiting for someone to accuse me of stealing it, then me having to explain how they likely didn’t even sell them there, what the connector was for, where I got it, what I was doing, etc. No such excitement happened, of course.) The #6 screw was a bit too big, or the threads were wrong. No-go there, so I tried the next size down, #4. I’ll take this time to mention that I had to guess that #4 was smaller in diameter than #6, and prove this experimentally. (Here’s a screw chart I think.) Lowe’s screws were kind of disorganized, so it took some time. I think I’ve determined that a “#6×1/4″” screw is #4 size, 1/4″ long. (I don’t think they had anything 1/4″ long.) I ended up with some #4×1/2″ that looked like they might fit, and the ones I got came with nuts in the package. Haven’t tried them in the connector yet, though; I didn’t have the courage to try and get away with opening a bag of screws. Too risky!

Then back to Harris Teeter with my new tape measure (from Lowe’s) to try and find a can again. I realized I missed the coffee aisle. So now I’m running through Harris Teeter with a tape measure that I’m sticking on every can I can find. Somehow I didn’t feel like this was going to get me picked up by store personnel, even though I bet it was more suspicious than some mystified guy spending 30 minutes in the screw aisle taking some strange metal object out of his pocket. Anyway, all coffee cans I saw were no-go: all their diameters were too large (greater than 3.66″, which is about the max according to the JS on the Cantenna how-to page; BTW, 2.88″ should be about the minimum diameter — and that’s a fucking tall can). So I scour every aisle, re-measure a bunch of cans, and still no success. I can say this: cans are usually either 2.5″ (I think; measure a soup can and remind me), 3.375″, or 4″. Nothing in the store that I looked at fits (including beer cans), so I’m ready to head out and settle for the Chef, when in desperation I check out the baby stuff aisle. Eureka! Baby formula. (Please note that I paid something closer to $3.50 before tax, if memory serves.) This can was the usual 3.375″ in diameter if memory serves, and I’m pretty sure it was greater than the needed height of 6.66″ (or 6.71″ according to the Cantenna JS page). However… now I seem to recall thinking it was 6.5″ high, which would be bad. I’ll check it again tomorrow. Anyway, it’s probably a “more perfect” can than the Chef, maybe. I can always try both. Once you get the Chef, you can’t give him back. (Well, I guess you can, but I don’t want to return the stuff. Maybe I’ll let someone else give it to a canned food drive if they want.)

Triumphantly I bought one can of baby formula and headed out. Tomorrow (today, technically) I build the Cantenna hopefully. If anyone wants some baby formula you’d best be at my apartment by 1130 tomorrow to collect it, else it goes down the sink. Going to borrow drills from some people. I want a laser pointer to use in aiming it for testing, too. I hope to get some cooperation from someone tomorrow to help me test it in open space across the apartment complex or something. I’ll probably try and use my GPS to measure the distance between the two points (by walking). Not terribly accurate perhaps, but it’ll work more or less.

I had to do some sick stuff with our name servers tonight to make sure that zones get updated both in the internal and externals views. Basically the notifies still get sent to the routable (Google gives more hits for “routable” than “routeable”; my spelling is hereby corrected) addresses, so I had to have the Linux firewall DNAT them to proper internal addresses. It was either this or add also-notify and notify explicit statements for every zone. Also, I have one zone that is dynamically updated, so to get it to synchronize between internal and external zones I had to actually have it send notify messages to itself (on a different IP address that the other view catches). Weirdness. I think this part, at least, would all be much more sane with djbdns.

Time for bed. I am so not a vampire lately.