The Treehouse Blog

Since the root zone was signed this week, I spent a bit of time today setting up DNSSEC validation on my home recursive server.  It was relatively painless (so far).  I did opt to not enable DLV though – not fond of it receiving every host name I resolve.

Resources:

• RHEL RPMs from http://people.redhat.com/atkac/bind/5.6-test/ – if someone finds a better source for BIND 9.7+ RHEL RPMs, I’d like to know.  I had no luck building from the Fedora SRPMs.
• http://www.isc.org/community/blog/201007/using-root-dnssec-key-bind-9-resolvers – instructions for setting up BIND to use the root key.
• http://fanf.livejournal.com/107310.html – A more thorough walk-through of setup.

One resource I would have liked to find and could not was a deliberately unvalidatable non-root zone/record that could be used to see a validation failure.  If anyone knows of or finds such a thing, please pass it along.  Now we get to wait for .com, .net, etc, to catch up to .bg and .uk in the publishing of DS glue for deeper validation.

UPDATE 7/22/10:  Just found the following site which makes available bad records for testing purposes: http://dnssec-tools.org/testzone/index.html

Are cell phones yet to the point where they can replace a hand-held hiking GPS?  Up until recently, I’ve been quick to dismiss this notion.  The announcement of Garmin’s latest hand-helds that appear to be moving closer to their cell phone brethren has me wondering.  Reports of the new touch-screen interface are about as bad as one would expect.

So, what are the issues?  I tried my G1 running OruxMaps on a 3.5hr / 10 mile hike in the mountains on Monday to get a better perspective.

Battery Life. It barely survived.  I would probably expect twice the battery life from my Garmin GPSMap 76S with a constantly running display.  Can the battery life issues be solved with an external AA-based battery pack to keep the cell phone charged?  I have no experience with these things.  Reviews indicate that ones without regulators aren’t worth much.  I might have to try one.

GPS Hardware. Cell phones may have GPS receivers, but it is not their primary function.  Most Android phones I’ve looked at seem to use the Qualcomm gpsOne chipset instead of a dedicated chipset such as the oft-mentioned SiRFstar III.  This is a cause for concern, since gpsOne currently seems to lack support for WAAS and likely is not as sensitive as the SiRFstar.  The upside of gpsOne is that AGPS will provide a faster lock when within range of the cell network.

Usability. Another major hurdle is the availability of high quality GPS software for the phone.  I’ve tried Maverick Lite, OruxMaps, and My Tracks and found them all to be lacking the necessary features of a hand-held GPS.  My Tracks is the Google-sponsored outdoor activity tracking app that was very recently open-sourced.  Maverick and Orux both provide offline map access (another must), but they seem to accomplish this with saved graphic tiles and not vector data as would be desired.  Any new GPS solution I get should have high-resolution topo maps included.

Durability. Hand-held GPS receivers tend to be waterproof and a bit rugged.  I’ve dropped my GPSmap 76s a number of times – and it once fell off my bike at 15+ mph.  There’s no way any phone I’ve owned would be happy with that kind of treatment.

Bottom line?  Not sure yet.  I do think the concept of a hand-held GPS is already starting to fade.  I’m not ready just yet to give mine up in favor of the cell phone.  I hope the newly open-sourced My Tracks starts gaining some useful hand-held features.

A few years ago, I decided to improve the light switch situation in my garage.  The garage had lights at either end controlled by pull strings.  It was a frequent hassle to walk from one end to the other, often tripping over a variety of obstacles, to get both of them on or off.  Having already deployed X10 to control a few things around the house, it seemed like a reasonable and economical idea to use X10 here as well.  I used two LM15As for load switching, two SS13As for control near both doors in the garage, and an RR501 to tie everything together.  Initially, the project seemed to be a great success.

Then it becomes apparent that the SS13As are not that great.  The adhesive backing would refuse to stick to the garage wall for extended periods of time, necessitating the addition of some screws to provide a slight ledge for them to sit upon.  They are also battery powered, and the stock batteries were nearly useless in cold weather.  Naturally, the colder times of year require the use of lights in the garage more often, and it became incredibly annoying to have to warm the switch with your hand and make multiple attempts to turn on the light… when the pullstring that otherwise would work is in reach.  My suggestion is to never use SS13As in anything but warm environments, and probably just avoid them altogether.  The one I had used inside would “forget” its code assignments and the coldness of the window sill was enough to keep it from working well.

To fix these issues, I revisited the idea of wiring regular three-way switches in the garage.  With the layout of the existing wiring, even the most creative ideas would require two new wires run the length of the garage, with one of them likely needing to be a 3-conductor that I don’t happen to have laying around.  And copper isn’t really cheap right now.  So, X10 was again looked at for a solution.

I decided to go with hard-wired X10 controllers, specifically the XPT4-W.  I installed these near existing wire locations with a minimal of effort – maybe 3 hours total. So, now I have fully functional control of my garage lights (probably even in cold weather), and didn’t need to run crazy amounts of cable for three-way switches.

It was with some great fanfare that AMPS met its death on February 18th, 2008.  But did it really die?  As far as I can tell, all that happened on that date was that the FCC no longer required cellular providers to make AMPS available, and many did eagerly turn it off.  But, unlike the conversion to digital television, there appears to be no requirement at this point for providers to abandon AMPS if it is still making them money.  That being the case, are there any AMPS providers still out there?  Public filings (available here) concerning AMPS status were made prior to the sunset date and reveal that some companies had a lot of AMPS customers still and had no plans to turn the service off.

Why do I care?  Because I loathe 47 CFR 15.121 and would like to see it abolished.  This is the section of FCC regulations that forbids the manufacture of devices that can receive, or be easily modified to receive, cellular frequencies.  This requirement only covers the Part 22 Cellular Service (824-849, 869-894 MHz) and not the all-digital PCS and AWS bands that cell service has expanded into.  With AMPS, conversations were transmitted using FM, and so could be easily decoded by any FM receiver that could tune to the appropriate frequencies.  With the digital services, more sophisticated handling of the signal (and even decryption) would be required, which apparently made it unnecessary to have the same kind of regulation.  As far as I know, this is the only restriction placed on what frequencies can be tuned by a receiver.  On freedom grounds alone, I have a big problem with that.  If AMPS does finally die – and I hope it does – I hope that 47 CFR 15.121 can die with it.

While hiking this weekend partly along the suspected area of the long-since-defunct Bedford-Harrisburg L3 cable, I found the apparent demolished remains of one of the repeater huts that had eluded me up to this point.  As they all are, it was not far off the road, near the top of the mountain at Upper Strasburg.  Guard rails have since been erected in front of what would have been it’s very small level parking area.  Nearby there were also portions of exposed L3 cable that had apparently been covered in rocks instead of buried below grade.  Really awesome, though unintentional, finds!

The map has been updated.

Demolished L3 Repeater Hut

Exposed L3 cable