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What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 12:42 am
by N126DL
First post!

I noticed this out the window on my last trip through ATL. What is this red-topped round object on a grid?

http://maps.google.com/maps?t=h&hl=e...4.435048&spn=0.001474,0.00284&z=19

RE: What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 1:09 am
by corey07850
It's a VOR (a navigational aid)

RE: What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 1:15 am
by Starlionblue
I'm going to guess at some kind of navigation aid.

RE: What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 1:45 am
by akiss20
Technically it is a VORTAC which is a combination of VOR and TACAN. VOR is the traditional VHF navigational aid used by civilian pilots. TACAN is a military system.

http://en.wikipedia.org/wiki/VHF_omnidirectional_range#Operation

RE: What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 3:17 am
by dairbus
Quoting AKiss20 (Reply 3):
Technically it is a VORTAC which is a combination of VOR and TACAN

To be more precise, it's a Doppler VOR with TACAN or D-VORTAC. The "grid" is part of the antenna. A doppler VOR is more accurate and is less affected by terrain and buildings so it's preferred for built up areas.

The TACAN antenna is the small white dome about 200ft south of the VOR.


Here is another view.

http://www.bing.com/maps/default.asp...yn7yxc91&scene=7175116&lvl=2&sty=b

RE: What's This Object On The Field At ATL?

Posted: Fri Jul 23, 2010 2:44 pm
by mmedford
Just to add to dairbus; it's a doppler VOR (iirc 50 transmit antennas, 1 monitor antenna) as compared to a conventional VOR (1 transmit antenna, 15 mailbox monitor antennas)... the "grid" is a counter-poist; which is apart of the reflection plane.

Also; the TACANs are slowly being phased out and they are becoming normal VOR/DMEs...

RE: What's This Object On The Field At ATL?

Posted: Sat Jul 24, 2010 12:04 am
by akiss20
Little side question,

Does anyone know why pure TACANs are marked on the Low-Enroute charts? I assume the military has its own charts and doesn't use NACOs (this is a WAG, I might be wrong). Are there any civilian A/C that can use TACAN?

RE: What's This Object On The Field At ATL?

Posted: Sat Jul 24, 2010 3:08 pm
by NBGSkyGod
Quoting AKiss20 (Reply 6):
Little side question,

Does anyone know why pure TACANs are marked on the Low-Enroute charts? I assume the military has its own charts and doesn't use NACOs (this is a WAG, I might be wrong). Are there any civilian A/C that can use TACAN?

The military does use NACO charts, and that is why they are charted on there. Its also the same reason TACAN channels are noted on VORTAC labels.

RE: What's This Object On The Field At ATL?

Posted: Sat Jul 24, 2010 10:09 pm
by akiss20
Quoting nbgskygod (Reply 7):
Quoting AKiss20 (Reply 6):
Little side question,

Does anyone know why pure TACANs are marked on the Low-Enroute charts? I assume the military has its own charts and doesn't use NACOs (this is a WAG, I might be wrong). Are there any civilian A/C that can use TACAN?

The military does use NACO charts, and that is why they are charted on there. Its also the same reason TACAN channels are noted on VORTAC labels.

Well there ya go, my assumption was false. I assumed the military would have its own charting office (it seems the military enjoys making its own version of everything) but that is not the case.

Good to know!