While trawling MERX, these locations came up; with some Google Satellite View snooping it was pretty easy to identify their locations. However, I'm light on details as to what system they support. Are they part of the "Strategic National Communications infrastructure"( citation )? I would guess that Cardiff and Riverbend are remotely operated by CFB Edmonton, and that Carrying Place and Point Petre are operated by CFB Trenton; but that's only a guess, based solely on proximity. Three of the four sites have the unmistakable LPH-89 antennas in their antenna farms, so I assume some of their duties involve HF communication.(LPH-89 Antenna @ USAF HF Receiver Site, Lincoln, California)The next time I'm near Trenton I'll certainly check out Carrying Place and Point Petre and hopefully get some better pictures of their antennas.