I wrote a map of amateur radio operators in the United States of America and related territories. See it here!.

Tools:

• sqlite3 python bindings with rtree support - Rtrees are one of the family of spatial trees. Particularly, they handle range-queries on large amounts of points efficiently.
• web.py - turn your python program into a web server!
• gmaps.js - This looked like a simpler introduction than the raw Google maps APIs
• geopy - Geopy converts addresses into latitudes and longitudes

The general flow is first pull down a copy of the amateur radio section of the ULS. Extract it, and feed it into simple a sqlite3 table. Next, geocode all the addresses into an R-Tree(This is actually still in progress). Finally, serve them up with a web.py JSON API to generate a bunch of gmaps.js markers.

Code is available on github. A major rewrite is in order to fully parse all the data available on the ULS, like licensure and expiration dates, FCC registration numbers, and other information. Additionally, a versioning scheme needs to be implemented so that only differences between ULS dumps will be processed. Also, geocoding the 1.2 million addresses will take a long time unless I use a paid service or distribute the queries. Additionally, running JSON servers on port 8080 tends to confuse proxy servers, so that'll probably need a more advanced deployment.

Size

Slowcookers come in sizes ranging from a pint, good for fondue or melting butter, to larger than 8 quarts. Some bases can hold interchangeable pots as well. Most recipes can be scaled down, but some recipes will be limited by size, like a slow-cooked chicken. To some degree, size also determines power consumption, so you may want a smaller one for a recreational vehicle.

Removable Pots

Many older slowcookers have the pot and base integrated. This make heat transfer more efficient and smaller than removable pot designs. However, the removability of the pot makes cleaning much easier.

Insulation

Some slowcookers come with an insulated base, which keeps the outside cool to the touch and makes the whole design more energy efficient.

Shape

Slowcookers tend to come in three shapes - circular, ovular, and rectangular. Circular pots seem the most common for medium and smaller sized pots; ovular and rectangular pots tend to have larger capacities. Shape really only affects selection if you're short on storage space.

Settings

At a minimum, select a pot with at least low and high settings. Avoid anything with an ungraduated analog knob. Some more advanced slowcookers sport a programmable timer, which is great for cooking recipies that need a few hours on high, then simmer on low, without human intervention.

The VR240

Eventide has been producing and updating their 24-channel audio recorder, the VR240, for ages. Common use-cases would be logging support calls or recording radio traffic. Two units eventually made it to my home without any tapes. One of them eventually got tore down at the hackerspace. Luckily, these units use a large(at the time) SCSI disk as a giant FIFO to buffer the tape writes. I've always been curious where mine came from, but perhaps they'll actually be able to tell me.

Disk Format

It seems the SCSI disk inside the VR240 was never meant to be removed and placed into a desktop. The disk does not actually have an MBR, but is instead divided into 1KB blocks. The first two blocks appear to be used as headers or indexing, the rest appear to have a 32-byte header and probably contain the audio. The header for the data-blocks appears to be:

• 3 bytes of block-counter, increments by 4 each block.
• 2 bytes of padding
• 3 bytes of walking bitfield. Starts at bit0, shifts left once per block, wraps every 24 blocks.
• 2 bytes: 0x2269
• 2 bytes: a very slow counter. Appears to increment every 40-50 blocks?
• 2 bytes: A few different values spotted here: 0xAA9C, 0x7FF1, 0x73D9, 0xAADF. More digging required.
• 6 bytes: 0x000700081418
• 12 bytes: unknown, could be the start of audio

Audio Formats

The VR240 supports three different formats. The manual describes them quite well, and there's some important bits of knowledge we're going to need later about the encoding in there too. Of note, independent of encoder output rate, the sampling rate is always 8kHz.

• 64kbps - This appears to be a raw mono 8kHz at the native ADC's 8-bit sampling.
• 32kbps - The manual mentions the DSP does some compression, but then explains that there are 4-bits per sample. This sounds suspiciously like analog-domain audio compression followed by quantization(or log-encoding, something like a-law or u-law).
• 16kbps - Similar to 32kbps, 8kHz sampling with 2 bits per sample.

Another note from the manual: "The 8-bit samples used in the VR240 actually have a dynamic range equivalent to 13-bit linear samples, but the 13-bit values are especially coded into 8-bit quantities." 86 pages in - it's G.726 u-law. So if we can organize the bytes, we should be able to snag somewhere between 16 hours and 3 days of audio.

Where is the Audio?

Assuming the disk is written end-to-end, it should be possible to play it with a raw audio player by skipping the periodic headers. But, there are some variables:

• Encoder bitrate - 64/32/16 kbps
• Bit-endian-ness - in 32 and 16 kbps modes, need to guess the ordering
• Sample signed-ness - could be signed or unsigned
• compander - although this should match, it should be possible to hear a distorted version with the wrong curve.
• Header noise/size - need to listen past the 8Hz(64kbps)/16Hz(32kbps)/32Hz(16kbps) glitch of the header playing

So there are 20 different ways the audio could be encoded, assuming we can guess the header size, and probably 10 of them need checking by ear. Additionally, RFC2422 states "No header information shall be included as part of the audio data.", so we're on our own as far as finding out how much audio is present per 1kB block.

The Display

Unless the display gamut can't be calibrated out, I'm not particularly picky, but the display resolution(1366x768) is a little low for a 14 inch laptop. The 15.6 inch's DPI would be unacceptable.

The Upgradeability

The upgradeability is great! You can move from a socketed low-end Sandy Bridge i3 all the way to a high end quad-core Ivy Bridge i7. However, the separate video chipset isn't socketed, so you're stuck with either what came on your motherboard or the integrated Intel integrated HD3000 or HD4000. With an Ivy Bridge chip, you can move from 1333MHz DDR3 to 1600MHz DDR3L. With two slots, you can seat between 1GB and 32GB, although 32GB seems to require and Ivy Bridge. Also, there's a dedicated M.2(NGFF) SSD socket for providing cache, in addition to the 2.5mm SATA 3(6gbps) port.

The Pointing Interfaces

The E431 provides a trackpad and IBM red-dot mouse. The red-dot mouse works exactly as expected, except that the mouse buttons usually located between spacebar and the trackpad are missing. This means reaching to the bottom of the trackpad, or leaving tap-to-click enabled.

I'm unsure what to think of the trackpad. It has both tap-to-click and depress-to-click. It reminds me of the early core-i macbooks, except someone forgot to disable tap-to-click. Luckily, it is highly configurable.

The CDROM

The CDROM is so bad it gets its own section. It starts with what I believe is some sort of nonstandard integrated tray. Once ejected, the tray flops around like a pancake, with at least a half-inch of slop. It is so loose I don't feel like I can insert a cd safely into it without holding the far end up with another hand.

The axle usually only engages one or two teeth. The solution here is to spin the disk, and if it scratches itself on the tray, you need to take it out and try again.

When running, it shakes my coffee table so hard that the my X60's LCD shakes.

Overall, optical disks will be dead once everyone has fast enough internet; I only need this one to reinstall windows.

Hard Drive Tray

Another design anomaly is that the hard disk tray is mostly clear plastic. Also, the plastic comes glued to the disk.

Also, the scant bits of metal on the hard drive tray are barely grounded by two strips of EMI cloth that appear to be added as an afterthought. The metal of the tray directly drags on the EMI cloth, which will likely wear it or the underlying glue out after a handful of insertions. Lenovo even has a note about this.

Finally, the difference between the 7mm disk and 9.5mm disk slot is spent with three pieces of foam. This is a neat idea, and the only improvement I could think of would be EMI foam to better conduct and disk heat to the metal on the other side of the bay. The foam also may cut down on noise, although it will be hard to replace if ever removed, although some disk manufacturers ship a thin matching shim with their disks that serves the same purpose.

Conclusions

I'm not particularly enthused with the build quality - there's a distinct lack of IBM sheet-metal making up the case - more like a Toshiba than my previous IBM Thinkpad. Also, the bloatware is strong with this one, but the price was right, and I know I can drop in a newer quad-core if it ever bogs down. Mousability is my only remaining serious concern.