Excuse the long question but something has me confused. I’m trying to learn VOR navigation and am trying to stay in my local area. Navigraph shows a VOR at a local RAF airbase, whereas Little Navmap doesn’t show it. However I loaded in to a nearby airport in the C172 Steam Gauge version and entered the frequency shown on Navigraph into the Garmin 520. It resolved the name of the VOR and gave me a radial and a distance, but the OBI refused to come alive, even after changing the CDI to NAV rather than GPS.
This leaves me thinking that I’m receiving something that the Garmin considers to be a VOR but that actually isn’t. What confuses me is that I did fly around and when I intercepted what the Garmin said was a radial I then tracked it dead on according to Little Navmap.
Some things that are shown on charts using what looks like the VOR symbol may be TACANs, or a combination of both. The one you’re looking at may well be a TACAN only, which means that only military aircraft will be able to use it.
I’ll give you an example that I know of. Go to KEYW on the World Map. If you don’t have them displayed already, open the filters and turn on navaids. Look to the northwest of KEYW and you’ll see the EYW VORTAC. Then look just to the east at Key West Naval Air Station. You’ll see a slightly different looking navaid there without the little black fillers. That one is only TACAN, and you won’t be able to pick it up with civilian receivers.
Thanks for the replies all. The Garmin is definitely picking it up, the name appears with the correct distance so I don’t think it’s something that civilian aircraft can’t pick up. Would Navigraph show the frequencies for military-only services? Or is FS doing something funky?
You need to be at a certain altitude , around 1000 feet above ground level, to catch the signal. You know that you have it when hearing the morse code,
Nice! I didn’t know you could retain a highlight in a URL! Thanks for the article. One thing I don’t understand is that the article says that VOR/DME (so not just DME) functionally is available to civilian aircraft. Is it that the OBI system in the 172 is too old to be compatible with TACAN?
As the article says, this is with a VORTAC, which is a VOR and TACAN combined at the same location. With TACAN only, this is not available to civilian aircraft.
Agreed. So my experience is this - the G520 can pick up the signal, so it’s not TACAN-only. The G520 screen gives me a distance (so it’s a DME) but also a radial (so it’s a VOR). This leads me to believe it is a VORTAC. My question therefore follows, why does the OBI in the 172 never come alive? I’m >1000’ AGL and the CDI is set to NAV.
Hi. That would make sense - the GPS using the word “radial” is what has confused me here - that’s only a term I had previously come across (in the world of aviation at least) in the context of a VOR, but now that I think about it is a fairly generic term used to describe a line through a circle
Hmmm, I can understand that and it does make me wonder if I am incorrect.
But, it would explain a few of the indications you are getting. I think it’s also possible that MSFS may abstract a few things and you have stumbled on the indications of one of them.
Do you find that this is an isolated example? If you tried the same thing at another TACAN station, do you get similar results?
I was doing a tour of RAF airfields when I discovered this - I connected to a few during the flight and they all did the same thing. I’ll try one in the US too though and report back
