The Treehouse Blog

This week I have been playing with my new PRO-2052 scanner. I bought this model because it has an RS-232 interface that can be used to control it. There is a free piece of software, sctl, that allows you to use it in Linux. I have had to tweak the code a bit for my purposes. I needed line buffering enabled to interface sctl with a PHP script, and also had to change the interfacing to make the ‘sreport’ function work with my model. I’ll probably post a patch at some point. So far, I’ve written a few cheesy scripts to log radio transmissions into a database and play them back. It’s not quite perfect, but it is doing what I want. It would be nice if this guy would release his source. I’d love to have the two-tone pager decoder that he has.

I’ve also been poking around various scanning sites. It looks like there still isn’t any progress decoding the OpenSky system used by the state of PA. Apparently it’s VoIP based. I also found a site with audio samples of various digital transmission modes. Many of the sounds are familiar from old movies and such. I think the PSK-31 sound is sortof like the bridge ambient sound from Star Trek TOS. Also found a great PDF with lots of communications tone tables, for Motorola Quick Call and others.

So, instead of watching DS9 or making my laptop more usable, I spent last evening trying to do APRS in Linux. Linux has drivers for using your soundcard for doing AFSK1200, but they are hardware-dependent, requiring a plain SoundBlaster or Windows Sound System-compatible card. Since I don’t believe I have any of these anywhere at the moment, let alone in a usable or mobile form, I started looking for alternatives. Soundmodem is a user-mode sound card interface for Linux that can do various encodings and interfaces with the Linux AX.25 stack, or can behave as a TNC sitting on a pty. It seems to work really well (and has awesome configuration tools) but it also consumes 25% CPU on my 1.5GHz Pentium-M… which is way too much, I think. Multimon, which is written by the same guy, uses almost no CPU, but can’t do transmission or interfacing with other things, just provides text output of what it decodes. The oscope feature it has crashes my box badly if you try to close it… no clue why, but I’m teaching myself to always disable that option.

Doug and I were talking on Thursday about the slowness of the Linux boot process, and it seems some guy at IBM has already discribed the parallel service starting that we were theorizing. I’ll have to ask Ian if Gentoo has implemented anything like this yet.

I won a Netgear GA620 (1000BaseSX) card on eBay last night for <$10. If works out OK, I might need to get one or two more. It seems appropriate that I’ll have gigabit in my house before CTI does at Trindle Commons… Fiber cable looks pretty cheap on eBay too, but there’s more singlemode than multimode it seems.

…And Ship’s 24TB 1.2M$ SAN has been moved from the basement of a dining hall to the computer center. Monday we’re moving all of KLN’s Sun boxes in preparation of its installation.