<P> TACAN is getting smaller: full TACAN coverage can now be provided in a system that can be carried on a single trailer weighing less than 4000 lbs, and set up by two people in less than an hour . TACAN Transceivers can now be as small as lunch boxes (with full coverage and range) and the antennas can be reduced from 800 pounds to less than 100 pounds . </P> <P> Because the azimuth and range units are combined in one system it provides for simpler installation . Less space is required than a VOR because a VOR requires a large counterpoise and a fairly complex phased antenna system . A TACAN system theoretically might be placed on a building, a large truck, an airplane, or a ship, and be operational in a short period of time . An airborne TACAN receiver can be used in air - to - air mode, which allows two cooperating aircraft to find their relative bearings and distance . </P> <P> For military usage a primary drawback is lack of the ability to control emissions (EMCON) and stealth . Naval TACAN operations are designed so an aircraft can find the ship and land . There is no encryption involved, an enemy can simply use the range and bearing provided to attack a ship equipped with a TACAN . Some TACANs have the ability to employ a "Demand Only" mode wherein they will only transmit when interrogated by an aircraft on - channel . It is likely that TACAN will be replaced with a differential GPS system similar to the Local Area Augmentation System called JPALS . The Joint Precision Approach and Landing System has a low probability of intercept to prevent enemy detection and an aircraft carrier version can be used for autoland operations . </P> <P> Some systems used in the United States modulate the transmitted signal by using a 900 RPM rotating antenna . Since this antenna is fairly large and must rotate 24 hours a day, it can cause reliability issues . Modern systems have antennas that use electronic rotation (instead of mechanical rotation) with no moving parts . </P>

Who is capable of receiving a tacan signal