Service Volumes of VOR's make no sense

The signal strength from a VOR decreases with distance. You are on a
straight line to the VOR from the moon but the signal strength would be too
low to create guidance.

--

Darrell R. Schmidt
B-58 Hustler History: http://members.cox.net/dschmidt1/
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"Steven P. McNicoll" wrote in message
nk.net...

"Antoñio" wrote in message
...

I was at a CFI safety meeting today and the subject of VOR service
volumes
came up. The AIM describes the Standard High Service Volume as providing
positive course guidance at varying distances depending on your
altitude--40nm at 1000ft., 100nm at 14,500ft, 130nm at 45,000ft, etc.

If the VOR is a "line of sight" signal device. How can there be varying
distances of service at varying altitudes? I mean, shouldn't I be able
to
pick up a VOR radial from the moon as long as no obstructions intervene?


Yes, and every other VOR on that frequency as well. The altitude/distance
limits ensure you won't receive an unwanted VOR signal. Note that the
service volume decreases from 130 miles to 100 miles above FL 450.