Figure 7 - P-8010014

INSTRUMENT NAVIGATION

The characteristics of TACAN are:

1. TACAN operates in the UHF Band. UHF frequencies, like VHF frequencies, are also

relatively free from atmospheric disturbances and are limited to line of sight of reception.

Therefore, the Earth's curvature and aircraft altitude will affect your ability to receive the

TACAN signal.

The TACAN system employs 256 two-way operating channels (1X through 126Y) which

correspond to UHF frequencies spaced 0.5 MHZ apart.

2. TACAN presents magnetic bearing information. The information presented is virtually

identical to that presented by the VOR.

3. In the T-34 aircraft, TACAN bearing is displayed on the #2 needle. The displayed

information is accurate to + 3/4.

4. TACAN identification signal. TACANs can only transmit the Morse code

corresponding to their 3-letter identifiers. TACANs are never capable of voice transmission.

Figure 7

5. TACAN is subject to 40 lock off. TACAN ground stations produce their bearing

information through a series of pulses which are spaced 40 apart. A properly functioning

airborne

TACAN receiver has the ability to interpret these pulses and to properly display correct

TACAN magnetic bearing to the aircrew. With a weak airborne receiver however, a

1-8

RADIO AIDS TO NAVIGATION