Wednesday, May 04, 2005

Overhead intel on Leitrim

Google Maps' new satellite photos feature provides a detailed and apparently reasonably up to date (probably 2003 or 2004) look at CFS Leitrim, Canada's main SIGINT collection site, located just south of Ottawa.

Here's a close-up look at the buildings. You can see the two new satellite dishes added in 2003, one on the west end of the line of radomes and the other on the east end. Interestingly, neither dish has yet been covered by a radome of its own (as of the time this photo was taken, anyway).

You can also zoom out a bit for a look at the whole station. Note the Pusher high-frequency direction-finding antenna array, codenamed CENTREVELIC, located just north of the buildings (shown in more detail here). Also interesting is the landscaping done in the 1960s for a considerably larger HF-DF array a short distance to the north-west of the Pusher array. As far as I can tell, this array, possibly intended to be an AN/FLR-9, was never built, and the site is gradually reverting back to nature.

Finally, the Google images provide evidence of another—even larger—type of circularly disposed array at the station. Note the two semi-circular fans radiating out from the vicinity of the station buildings, one fan north of Leitrim Road and the other south of the road. The change in vegetation makes their outlines easily apparent. A close-up look at the southern fan makes some of the structural details visible. Anyone know what kind of array this is? I'm guessing it's a series of vertical log periodic antennas strung between towers and oriented at 15-degree intervals from each other to form a semi-circle. But that's a guess, and not what I would call an informed one, either.

[Update 7 October 2008: Well, it turns out I was right—about it not being an informed guess. I did a drive-past in August and there are no LPAs in the new array. Jerry Proc has some details of the rhombic arrays formerly at the station and the decision to replace them with the new system on his Leitrim - Old Antennas page.]

[Update 27 May 2009: Should have updated this about six months ago. The new array is known as a Beverage rosette array. The ever-reliable Jerry Proc has the details on his Leitrim - Current HF Antennas page.]


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