Depleting usable bandwidth since April 30, 2000
You've read about it in Slashdot, you've heard people buzzing
about it. AT&T
recently dumped a large chunk of its old microwave relay network, a little known cold war relic, on the auction block for
anyone to purchase.
Luckily, many of these sites have fallen into the hands of some very cool people -- Amateur radio operators and radio geeks --
who cater to both commercial and amateur radio use of these sites in high places.
If you are interested in colocating at this site (Mt Baldi) outside of Enumclaw Click Here
On a cold December morning, Ken Caruso and Casey Halverson from SeattleWireless set out with David Josephson and Scott Cronk.
The weather called for a storm front, and was probably the cause of all the wind. Gusts of at least 60 mph pounded us as we stepped outside the vehicle or a moment to catch a view of the sights. Scott called this area Picture Point, and we can see why!
Left: Ken, David, and Scott check out the view
Right: Looking in the direction of Seattle from a mere
couple thousand feet -- with several more to go!
After a lot more climbing and driving, we came across the AT&T microwave site. Pirched on top of a mountain peak, it was a firmilar site. A large tower reaching up into the sky, with a large array of late 1960s style microwave horns, and a large cement building below. But this was no ordinary building, it was a bunker!
The walls are 12 inch thick cement. A 12 mile run of underground power, complete with its own mini substation, supplies the site with 800kva of electrical service. Inside is a 350kva deseil generator, and to back that up, a 80kva bank of batteries. The site sounds overbuilt, but the effort paid off. In what is considered a harsh environment, the site stood 40 years without sign of wear. It could probably take 40 more easily. The Bell way works.
Left: Exterior of building, by enterance
How'd you like to climb that with 60 mph gusts?
Center: A view of the horns pointing eastward. The tower is pristine even after 40 years of harsh weather
Right: Back side of the bunker-like structure
Inside, the facility was clean and spacious. 23 inch racks carrying various telecommunications equipment scattered a rather vacant room. It was not a tight space and had plenty of room to grow. There was a lot of microwave gear and waveguides located on the tower side of the building, and a few racks containing what appeared to be a cross connect and alarm panel. Since the facility was designed in the 1960's, we were not suprised when we spotted several vacuum tubes and other dated hardware.
A view from the corner of the room
Left: Can you spot the vacuum tubes and relays?
Left: Microwave gear
Center: Misc. equipment -- possibly some sort of alarm panel
Right: Array of microwave gear left behind by Ma Bell
Right: GM diesel (about ~350kva)
Left: View from roof of bunker
Center: Looking towards cloud covered seattle
Right: (click for larger image) Seattle peaks through the clouds in center
After a tour of the facility, Ken and I (Casey) set out to get SIGNAL! A few questions popped up into mind....will 802.11 framing have timing issues at this distance? will there be too much noise? Since nothing was pointed our direction and properly aligned, we did not expect much.
It turns out that was not the case. With one twist of the antenna, several downtown Tacoma access points came to life with very reasonable signal levels. Home access points, linksys's and the like. Swinging the antenna the other direction towards downtown seattle, we saw several "high profile" wireless networks that we tend to see on a regular basis. Our unaligned end-point, a good 38 miles away facing in a southern direction towards us, was reporting -76dBm signal strength of an unknown signal-to-noise ratio -- since the prism chipset does not properly report the noise level (static at -100dBm). Still, this was very promising. With a storm front coming in (inversion) and fog on the ground, this is probably as worse as it will get. Inversions tend to reflect RF energy out into space in our Mountain-to-Valley situation.
For those of you who dont speak dB, in english, -76dBm is a very good signal strength. You probably don't even see that at home in the other room. Our card provides 11mbps reliably (Bit error rate of 10E-5) at -89dBm. That gives us a 13dB buffer before the card starts to scale back its data rate. And a 19dB buffer before its 1 mbps rate becomes unreliable.
Eventually, Ken and I got really cold ... but we hung out just long enough to get this picture. Yes, we arent very happy. High wind speeds and a brisk temperature of 30-something degrees is not pleasent.
A'top ye ol' microwave bunker - Ken left, Casey right.
It was too cold for any throughput testing and so we later headed home.
Next issue: Ken and Casey's wireless install