Today we did an easy 35 mile ride up to Burney with Mount Shasta, over 50 miles distant, looming large on the horizon.
Along the way we detoured a few miles and visited the Hat Creek Radio Observatory where we scored a fantastic and detailed tour from the site's sole remaining employee, UCB software engineer Colby Krabill. See, the observatory's funding has been declining for some while now back but back in April it ceased astronomical operations. It's being kept in preservation mode with the equipment running, cooled, and monitored.
Anyway, Colby has been involved with the observatory for about 10 years now and has lived on site with his family since 2008. With that and the fact that he authored a significant fraction of the complex software running the whole ship he's *the* authority on the site and the Allen Telescope Array (ATA).
Two hours after arriving we reluctantly headed out (incidentally, you can only get into the place on foot or via bicycle presently). The good news is that it looks like the Air Force is about to step in and get the place back up and productively running -- retasked with an orientation towards work with artificial satellites but nevertheless running. We're hoping that works out and that the place is allowed to eventually expand to its originally-envisioned size.
Okay .. non-techie people will want to stop reading this post here. :)
This is a picture staring directly at one of the log periodic receiving antennae housed at the focal point of the dishes. From front to rear you're looking at about four feet. The things have an incredible10 GHZ bandwidth -- all of it usable at once and with fairly simple fine tuning available via physical adjustments if additional gain is needed. They've got a new design prepared that increases the bandwidth to 20 GHZ by sacrificing the lowest gig -- a proposition that's looking good since that's where the bulk of their terrestrial noise is anyway.
Another fascinating aspect for me was the air cooling system they have for the electronics housed out in the antennas. The antennas are arranged in physical clusters. In each cluster there is a small building with an air intake, filters, and a pump. From there the air then heads out through buried lines to the individual telescopes and into the actual electronics enclosures. The nifty aspect of this is that they're using the geothermal cooling aspect of the buried lines to regulate the temperature of the air! Grand. They've had some problems with the shorter runs due to the volcanic sand, tho. The sand it very thermally conductive but only if it's wet -- which it almost never is. If the place ever gets to get fully running again or expand they plan to run the lines deeper and fill the trenches with potting soil.
Kind of looks like a bit of old style computer room here but what's going on in this picture is unsual. The analog radio signals are converted to *analog* light on fiber at the antennae and are then run into here for conversion to digital, beam forming, further processing and recording. If I heard Colby correctly, they can process an entire 600MHZ (800?) window at once. The combined system is very flexible and very fast. Hopefully the new tasking and funding will become a reality and the system can be developed further.
Thanks again to Colby for taking the time to give us such a wonderfully complete tour. It made our day.
/David