Denver ARTCC radio sites in Colorado

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natedawg1604

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So I just recently got into aircraft scanning, and I have a question about the Denver ARTCC radio sites. Based on a cursory review of this map API (Military Comms Map of ARTCC (Air Route Traffic Control Center) Transimitter Locations) it seems that ARTCC radio sites in the Denver-Metro area are not situated atop any of the popular "radio tower mountains" such as Lookout, Squaw, Thorodin et al. Are the ARTCC towers intentionally designed to only cover airspace, such that they can't be easily heard from the ground?
 

tech020

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Your sort of answered your own question. Ground sites for ARTCC are usually on no more than 40' platforms. They are sited to enable coverage above the horizon, so no downtilt like high land mobile sites. The radio horizon for an aircraft depends on its altitude. At 35,000 ft, I believe its about 250 miles. The typical antenna used by the FAA is a coaxial diipole that covers 115-135 Mhz with unity gain and a wide veritcal pattern. Transmit power can varies by requirements from 10 to 50 watts.
 

natedawg1604

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So today I was looking through the 56-day National Flight Data Center files, specifically the AFF file. Based on the latest AFF file, it appears there are basically 2 ARTCC site locations in the Denver-Metro area, as follows:

*3 closely adjacent sites in Watkins near the Orica Mining Co. (39.644167, -104.586944; 39.644167, -104.590278 - this second pair of coordinates is shown in 2 site listings)

*1 site in Longmont near East County Line & Wasatch road (40.24, -105.054722)

Does this sound correct? Is anyone aware of other ARTCC sites in the Denver-Metro area? (I would *think* physical RCAG locations would be fairly up-to-date in the AFF file releases, but who knows...)
 

AI7PM

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I believe the site (Mead) on County Line, is a BUEC site. FAA jargon, BackUp Emergency Communications. If a main RCAG fails, the controller hits a switch and begins using these alternate BUEC sites. There are also BUECs at the ARTCC building in Longmont, and in Parker. Redundancy is good in that business.

The two buildings near Watkins, are the normal RCAG site for several sectors in the area. Next one North is on the chalk bluffs South of Cheyenne. Going South, Eastonville and Pueblo. All readable from I-25.

As for AFF data, it's pretty much not designed as a public information source. Bits and pieces are found here and there. I see it used in many scanning sites as "The Facts". A simple drive by or hour spent with a scanner will show freqs being used that weren't published, or old freqs that are no longer there still published. Same with the RADAR site info.
 

nd5y

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(I would *think* physical RCAG locations would be fairly up-to-date in the AFF file releases, but who knows...)
In many cases the locations are not accurate and have been like that for decades.
Sometimes the published locations are for airports or navaids and in real life the site is nowhere near.
Sometimes the real life location is within a couple miles of what is published and is easy to spot on Google Earth or map web sites with satellite/aerial photos.
 
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nd5y

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look at 40.2400, -105.0553 on google street view. You can see it has the US Govt warning shield on the fence, 4 microwave antennas on the tower and 2 FAA dipole antennas on the building.
This isn't a typical RCAG site.
 

poltergeisty

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look at 40.2400, -105.0553 on google street view. You can see it has the US Govt warning shield on the fence, 4 microwave antennas on the tower and 2 FAA dipole antennas on the building.
This isn't a typical RCAG site.

Thanks. No, that wasn't it. I believe what I saw was the ATC building and if I can remember right I heard or read it was indeed in Longmont.

I use mapper.acme.com BTW. Works nice finding mountain bike routes using my GPS or GPS App. I actually used acme mapper to help make Area-51 in FS2004. :D

Edit- I see what appears to be two propane tanks? Are those for a backup generator? You'd think they would use a larger tank.

Edit2- Okay, I see two larger silver tanks next to the other building.
 
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natedawg1604

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Maybe I should submit a FOIA request asking for information identifying the actual physical site locations of primary & backup RCAG sites within Colorado or the entire ZDV. There *must* be a master site list somewhere in existence, no? I would think ARTCC controllers at the very least would need this information so they can properly prepare for contingencies and provide accurate instructions to pilots flying over their sector.
 

AI7PM

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I'm guessing that big tower is used for microwave links to other RCAG sites. I do see a bunch of antennas on the building itself, could those antennas constitute a primary ARTCC radio site?

Various data comes in and goes out via the microwave antennas. RADAR and RCAG as well. In the 80s the FAA interconnected the previously separate 20 En Route Center microwave systems. This created an agency owned nationwide network.

The comm antennas atop the building are BUEC. The location of the building provides a good BUEC site for sectors North through South, particularly high altitude sectors.
 

nd5y

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How on earth do you interpret the coordinates?

CO40-11-13.940N 144673.940N105-07-35.940W378455.940W
That's two things run together.

I tried, 40-11-13.940N 105-07-35.940W
That's the latitude and longitude. Replace - (dashes) with a space and it should work. If that doesn't work the replace the dashes with spaces, remove N and W, and make the longitude negative (western hemisphere). Sometimes separating the latitude and longitude with a comma can help depending on the web site.

40 11 13.940N 105 07 35.940W or 40 11 13.940, -105 07 35.940 should work on most mapping web sites.

and

144673.940N 378455.940W
I don't know what that is. Might be some military grid system or something the FAA uses. It doesn't look like UTM.
 
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