Re: R-4808N Fixes and Janet Routes

Message posted by Salty on January 26, 2007 at 9:40:04 PST:

I did some research and came up with the following. The FAA allows the outer marker to be no more than 800 ft. off the extended centerline of the runway. Given this and that they typically have a fan shaped radiation pattern, 2000 ft. off laterally means an approx. 45 degree angle from the marker to the plane, so now I don't think the outer marker is located at the old location.

At first I thought the scaped out hill was some sort of lookout (or a nice place for a picnic), but it isn't a very good one with a bunch of other small hills right around it. It's very possible that the OM for the new runway is at this location. The antennas are very small, and even the building need not be too large, potentially small enough to get washed out in Google Earth (see an example at So I think you made a good catch here, Jeorg.

The XSD NDB is a little odd in my eyes, as the posts imply a 300 ft. horizontal dipole, yet there's some impressive ground radials, used for vertical antennas. Perhaps a vertical was located there at one point in the past.

As for PYD, I think the resolution at Groom isn't as good as the TTR images, so the posts might not be visible if it is a dipole. There appears to be the shadow of something tall (like a vertical) across the southern edge of the old marker building, but no ground radials, as has been pointed out by lone wolf before. I tried to see if there was another shadow a few hundred feet away, but it's hard to tell in all that scrub.

Concerning another mystery location that's been bugging me for quite some time, there's another road that leads even further south from near the old marker building, and it looks like it sees some use once in a while. The end (or at least the end of the more used part of the road) ends at 37 6'40.68"N, 11541'17.45"W, which is out of the range of the good resolution images.

Attached link: Example outer marker building

In Reply to: R-4808N Fixes and Janet Routes posted by Joerg (Webmaster) on January 24, 2007 at 9:29:21 PST:


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