Unusual Radio

One of the things I like about ham radio is that there’s something for everyone. You can go for contesting, where the real pros will be be working 300+ stations an hour, working on contacting every region in the contest for maximum points. You can sit around and chat with your friends across the country for hours on end. You can interface your radio with a computer and use one of several digital technologies (an area with lots of innovation.) You can work through satellites. You can transmit images.

But there are some neat ones out there. The lowest-frequency ‘official’ ham band is 160 Meters, or 1800-2000 kHz. (Slightly above the AM broadcast band.) But it turns out there’s a 1750 Meter band, down around 175 kHz (0.175 MHz). It’s an unlicensed band, and is classified as “Very Low Frequency.” (VLF aficionados are often termed lowfers.) For the heck of it, I tuned down there (I wasn’t really sure if I could tune that low, actually). All I got was lots of localized noise, but it turns out that there’s a hobby called NBD DXing, or hunting down far-away beacon stations. (This isn’t strictly ham radio as much as a radio-listening hobby outside the ham bands, but still…)

Here’s a fun one: QRSS. It’s basically very low-speed Morse code, but part of the appeal is that it takes only a couple Hertz bandwidth. (Voice signals tend to take in the neighborhood 20 kHz, or 20,000 Hz, of bandwidth.) This also allows for very fine-tuned filters, permitting the signal to be picked out of very strong interference. The concept is really pretty bizarre, I have to admit.

Based on that work, someone developed DFCW. It’s a twist on Morse code where, rather than having dits (short / “dots”) and dahs (long / “dashes”), you have one length (dits), but you use two different tones, speeding up transmission. (Of course, “speeding up” refers to speeding up something described as extreme slowspeed, so it’s still slow.) It’d be interesting to see if this ever becomes used in lieu of ‘normal’ Morse code.

And then there’s Jason, a “keyboard-to-keyboard” digital mode which is designed to use under 5Hz bandwidth. Like the other bizarre slow-speed modes, this one is predominantly used on VLF.

So after taking the radio down practically as low as it would go, I started turning around the VHF frequencies, where more common, local FM communications take place. Even though we have some great lists of repeaters, it’s fun to just tune around the band sometimes. I stumbled across a repeater I never knew existed, where I caught the end of a QSO about fire towers. Much like some of the other stuff I’ve mentioned, it’s not strictly ham-related, but it was pretty interesting. There are apparently still a bunch used in Massachusetts. Mixing what I heard and what I found on Wikipedia, it’s actually pretty interesting. They usually cover huge areas (hundreds of square miles), watching for fires during the ‘fire seasons.’ When they observe smoke, they’ll obtain a bearing and can approximate distance. But the way they’re really meant to work is that a couple different fire towers will observe the same thing, and they can triangulate, with pretty good accuracy, the exact location, and have the fire crew dispatched. I thought they were a thing of the past. If they’re not busy, they’ll often welcome visitors; some even keep a guestbook.

Oh, and software-defined radio is an emerging trend in ham radio, too.

I’ve got to upgrade my license!


In the world of cryptography, people hate the concept of security through obscurity

In a nutshell, they argue that using a ‘secret’ means of securing something is no good. On some level, they have a valid argument. On another level, it’s more of a zealous ideal that doesn’t make any sense in the real world.

I’ve always preferred a more pragmatic approach: security through obscurity is a great way to buttress an already-secure system. If your non-obscurity approach (“security by design”) is complete rubbish, security through obscurity is only as good as your obscurity.

The government used a mode of encryption called Fascinator. You sometimes see radios with Fascinator encryption modules for sale on eBay. It’s very, very illegal to own Fascinator equipment, because it’s somewhat of a classified mode of encryption. Not much is known about how it works. Isn’t that security by obscurity?

Here’s a more simple argument: a business keeps its money in a safe. The safe is somewhat secure: you need the combination to open it, and you can’t really pick it. On the other hand, a stick of dynamite will also open it. I’m hardly a safe expert, but many businesses, at least in fiction and the olden days, kept their safes in pretty prominent locations, and, if not that, in easy-to-guess observations. If I visit an establishment a few times a week, I might become very familiar with where they keep their safe. If I decided to rob them, all I’d need was some dynamite.

But now suppose that the business is owned by someone who thinks outside the box a little, and who places the safe somewhere bizarre: say, the employee restroom, or in a restaurant’s kitchen. Those who visit the business probably won’t even know that there’s a safe, so someone who’s planning on some safe heists might not even bother with their business.

The argument against security through obscurity is that, if someone knew where the safe was kept–an employee, perhaps–would be able to get to it with no additional effort. And this is a valid point, but it misses what I think is the more important point: if you used it with a “secure by design” system (e.g., the safe), it’s far less likely that people would even know about it in order to break it.

In a computer setting, I thought about (but haven’t taken the time to accomplish) running sshd on a nonstandard port. sshd is a very secure protocol and I use strong passwords. But running it on a nonstandard port: hiding it: security through obscurity would provide me with an additional layer of protection.

In the past, I had an interface to directly manipulate the blog comments table, allowing mass deletion easily. It was something I hacked together one night, and never bothered password-protecting it. It was a ‘hidden URL’ with no links, and the URL was just a random, meaningless word. This is what the security through obscurity folks rightly condemn: anyone who looked through my browser history, or who guessed the URL (very unlikely?) would have been able to do serious damage to the database. But I was the only one who ever knew it existed, and the logs confirm that I was the only one who ever accessed it. Of course it’s a bad idea, and I agree that security through obscurity, as the only means of defense, is a horrible idea. (Despite it having worked perfectly for me.)

But I can’t stand when people go against anything that includes security through obscurity in any sort. It can only help, just don’t rely on it exclusively.

Car Cleaning Advice

I have to admit, I’m obsessed with keeping a very, very clean car. I’ve probably been waxing my car twice a month lately. (Which is probably more than is worthwhile?)

Anyway, I picked up some polish today, and, driving home from the store, couldn’t help but take notice of how the cars I passed looked. I found that most cars looked decent: not too many had really dirty, dull, or otherwise bad finishes. But not too many jumped out at me as looking amazing.

Testing something I’d started to think, I spent some extra time cleaning my car to make sure the wheels got cleaned thoroughly. Not only do they pick up lots of crap from the road, but brake dust makes them even dirtier. So I cleaned the wheels of both cars, along with a bit of wax. (I’m actually far from the only one to suggest that waxing wheels makes sense.)

Computer Pricing

So a coworker/friend is toying with starting an Internet cafe overseas. It looks like OSs such as Knoppix and Ubuntu are somewhat common in those setups, partially because they’re free, and partially because they’re easier to lock down.

So I went to Dell’s site, and began playing around with their configuration utility, trying to put together the cheapest machine possible. I figure we need like a 700 MHz processor, 512 MB RAM, and a CD drive. A hard drive is nice, but not necessary. (In fact, more secure.) My findings:

  • The system ended up costing $529, but you can lease it for $16/month. (This may actually be beneficial in this situation.)
  • The cheapest processor I could find was a Sempron 3400+, but the website never defines what this is. Knowing a little bit about computers, the only thing I’m able to tell you is that it’s almost certainly slower than 3,400 MHz.
  • “Windows Vista Home Basic” is the cheapest OS I could select. (They apparently sell certain PCs pre-loaded with Ubuntu… I’ll have to try to find them.)
  • Only having 512 MB didn’t surprise me, but I didn’t expect a 160 GB hard drive to be the smallest.
  • Remember the old days when a CD-RW was the sign of a pricey system, and if you could read DVDs on it, too, it was cutting-edge? Now I had the choice between that and a DVD burner.
  • No speakers are included. Given that it’s for an Internet cafe, I think this may be a good thing.
  • I deviated from my “cheap as possible” plan and sprung for a 13-in-1 card reader for $20 or so, figuring it’d come in handy in an Internet cafe.
  • The 56kbps modem is basically free. I removed it, but it didn’t take anything off the price, so I included it again. Better safe than sorry?
  • MS Works 8 comes ‘free’ with this install. No one likes MS Works, but I digress.
  • 1 year of in-home service is included. Maybe I shouldn’t have gone with the “Consumer” machines.
  • It includes Yahoo! Media Jukebox and 6 months of AOL. Two things we’d get to uninstall as soon as we took delivery of them.

Cynical rants about that stuff aside, though, it amazes me what you can get these days. I was reading through the circulars, and there are a lot of $800 laptops that can smoke any of my current machines. It’s hard to buy hard drives under 160 GB. (OTOH, it’s hard to buy hard drives over 160 GB for laptops…)