Bob Moore wrote:

"M. J. Powell" wrote

Except ICs instead of valves?

It wasn't the size of the electronics, but rather the
large antenna array required of the VOR system. A VOR
antenna must be permanently aligned to the earth,
something not possible with such a large array onboard
a ship. The TACAN system operating on a different
principle than VOR solved the size and alignment problems.

The writeup at
http://www.radarpages.co.uk/mob/nava...can/tacan1.htm
has already been mentioned.

Aside from size and earth orientation, TACAN has two advantages
over VOR for shipboard use.

1. TACAN uses a bearing reference direction of due east. For a
shipboard installation, that means a properly corrected compass
reference and a means of correcting the antenna orientation.

2. TACAN incorporates a ranging transponder (DME) in the
transmitter site. The aircraft interrogates the system, and the
site's transponder responds after a fixed 50 microsecond delay.
The site's azimuth and range are typically displayed on a
combined bearing/distance/heading indicator. The combination of
bearing and range display clears up any of the to/from confusion
possible with VOR sites.

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