Stubby wrote:

Hilton wrote:
Bob Moore wrote:
A VOR

antenna must be permanently aligned to the earth,

Why? Why not have a heading indicator (or DG) to drive the 'angles' (i.e.
phase) it sends out?

An advantage of VORs over TACANs is the VOR antenna does not physically
more, whereas it does in a TACAN. Electronic "rotation" of the antenna
intuitively makes shipboard use easier, but I might not understand ships
enough!

Operating frequencies dictate the size of the antenna array.
Compare this picture of a TACAN site at
http://en.wikipedia.org/wiki/TACAN with this one of a VOR site at
http://en.wikipedia.org/wiki/VOR.

Other advantages:
Range: TACAN DME has a maximum range of 300 NM miles. VOR
reception range is limited to 25 - 130 NM, depending on the
site's transmitter power.

Bearing accuracy: TACAN can provide bearing resolution of +- 1
degree. Typical VOR bearing accuracy is +- 2 degrees.

A bearing error of 1 degree at 100 miles isn't likely to be
critical on land, but that same error at sea can mean the
difference between finding your carrier and a very long swim
home.

| George Ruch
| "Is there life in Clovis after Clovis Man?"