September 19, 2013

CFS Lac St. Denis and GATR Site

Credit: Yves Charbonneau - Flickr
The 2nd closest Pinetree Line station to my home is RCAF Station Lac St. Denis / CFS Lac St. Denis, but I haven't been in any rush to see it.  Because the station was so close to Montreal, once it was decommissioned, it was sold to a succession of (inept) businesses who have ruined it for me.

Reportedly someone tried to make the operations building into a castle for a theme restaurant.  I'm unsure what else has been tried, but the paint ballers and graffiti artists have had their way with the building as well.  Most of the locations I'm visiting are remote, and too far out of the way for someone to casually tag them.  I love seeing urban decay, but this has more "urban" than the rest of them.

As it turns out, while researching old maps and collaborating with the The Air Defense Radar Veterans' Association who run the Online Air Defense Radar Museum, they mentioned they were unsure where the CFS Lac St. Denis GATR Site was.  Most of their people are in the USA, so, following on the heels of figuring out where the CFS Foymount GATR site was, and after seeing the Bing satellite image that sure looks like the right building, I volunteered to go and check out the spot they suspected, which was likely operational from 1962-1985.

As it turns out, Lac St. Denis isn't that far from several places I remember, or remember hearing about, from my youth growing up in Montreal; Saint-Sauveur, Morin Heights, Sainte Agathe, Mont Tremblant, Saint Donat, Sainte Adele, etc...  I wondered if as a child I'd ever seen the radomes when they were still standing... I doubt it.  There would have been no reason for me to take a highway that would have taken me near Lac St Denis.

As it's only ~3hrs from home, I'll pop up on a weekend sometime soon and check out the GATR site.  It looks as though it is being used by a telco or other company who would need a microwave repeater; there seems to be at least two on the site.  The original building looks like it's still standing, and I'm looking forward to taking lots of pictures.

I'm sure the road is in good enough shape to accomodate telco trucks who would maintain the microwave repeater at the top, but I don't know if the road is gated at the bottom.  Worst case scenario, the road to the top is ~2.5Km long, certainly walking it is possible.

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I can confirm that indeed it is located at (45.99949, -74.34638) at the end of a very well maintained road, with no obstacles, and a two-wheel drive sedan made it to the top without incident.
At the top you will find the original GATR building now being used by local private companies to house, presumably, modern repeater equipment.  The building would have likely housed a AN/FRT-49 (a 20KW High Output radio amplifier) attached to a AN/GKA-5 TDDL transmitter, meant to establish a data link with the interceptor for relaying target intercept data.)  The AN/FRT-49 was a big piece of equipment, it took up 3200 sq ft, and weighed in at 45,200lbs and had to be liquid cooled.  The AN/FRT-49 was a high power klystron linear amplifier, so care had to be taken to ensure the staff at the GATR sites were not exposed to X-Rays generated by the equipment; part of the weight of the system was heavy lead shielding inside the cabinets.(ref)  When moved it had to be lifted by forklifts and transported by flat-bed truck; this wasn’t a small radio transmitter.  At 20MW the transmitter was usually remotely located from the radar, in this case away from CFS Lac St. Denis operational site, so it wouldn't blot out the radar equipment with a massive amount of interference.  This was the same strategy done with most GATR sites.

"In addition to TDDL (data link), every GATR site had voice radios, namely AN/GRT-3 Single-Channel Transmitters, AN/GRR-7 Single-Channel Receivers, and AN/GRC-27 Multi-Channel Transceivers.  In the 1975 / 1976 time frame, all GATR Sites still in operation were upgraded under Project RIVET SWITCH (ed: USAF) to radio types AN/GRT-22 Single-Channel Transmitters, AN/GRR-24 Single-Channel Receivers, and AN/GRC-171 Multi-Channel Transceivers." -Tom Page, Historian, Online Air Defence Radar Museum

Also at the site you will find two original wood "antenna poles" still in use, the original foot pegs are still attached, and one of them still has the cross pieces that the original antenna would have been attached to.  The roof of the building isn't original, but the original flat roof has been replaced with a sloped roof.

The gate is no longer anywhere to be found, there are chunks of what look to be telephone poes - but are really antenna poles - lying around, and the original fence with barbed wire is visible at the entrance (where the gate would have been).  I did not investigate in the bush if the perimeter fence still encircles the property entirely.  The property is heavily overgrown with under-brush; small stuff, no major trees have grown up.  This could be due to potential liberal use of herbicide - not uncommon at the time of construction.  There is also no obvious "no trespassing" signage posted.

Big thanks to Tom Page of the Online Air Defense Radar Museum who helped me find this gem :)

Note the two cross-members at the top of the antenna pole

Note the foot pegs on both poles, and their unusually tall height.
(pole on the left side of the picture)

CFS Lac St Denis 1980s(?)
(Date and Credit Unknown)

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