1) Decca chains are designated by an alphanumeric code Report

OA, OB, OC, OD...

OB, 1B, 2B, 3B

OA, 1B, 2C, 3D

2) The separation between fundamental frequencies Report

30 Hz

50 Hz

25 Hz

3) D.N.S. the hyperbolic patterns are divided into zones and lanes. Zones are designated by letters Report

A.B.C.D..... J

A to J, starting at marker end of the master/slave base line

As in (ii) & sequence of letter repeats as necessary to cover the whole pattern

4) The D.N.S. transmitted signals cannot be compared in phase directly since Report

They are very low frequency

As in 'a' and the are not synchronized

They are of different frequency

5) The purple and master can be phase compared at Report

24f

18f

30f

6) The red and master can be phase compared at Report

30f

24f

18f

7) Number of lanes per zone Report

30 purple

30 purple, 24 red and 18 green

18 green

8) A better S.N.R. can be achieved in D.N.S. by Report

Dividing the received signals down to fundamental

Comparing the received signals with fundamental

All above are correct

9) Type of antenna used with D.N.S. Report

Capacitive

Inductive

Depends on type of aircraft and availability of space

10) MTCS Report

The antenna of D.N.S. is mounted as near to the centre of the aircraft as possible

As in (i), it could be either above or below the fuselage

As in (ii), if below a fixed 180

11) LORAN C is a Report

CW hyperbolic navigation system transmitting at 100 KHz from all stations

Pulse of 100 KHz R.F. are transmitted from all stations

all above are correct

12) MTCS Report

In LORAN C. the delay between the time of transmission of the master and each slave is varied as per the radiated power

The receiver in aircraft, receives the slave signals in the same order after master

ATA

13) In loran C. system, mutual interference is avoided by use of Report

Similar pulse repetition periods for each chain

Different pulse repetition periods for each chain

As in (ii) and there are total eight basic rates

14) There are a total of Report

Six so called basic rates, each of which have eight specific rates.

Eight so called basic rates, each of which have eight specific rates

Eight basic rates, each of which have six specifics rates

15) The LORAN C transmission chain are identified by their Report

Basic rates

Basic and specific rates

Pulse repetition period

16) Groups of pulse trasmitted from each station once during repetition period Report

Six

Eight

Six and Eight

17) Full automatic equipment for indexing or cycle matching Report

Eight cycle is taken

Third cycle is chosen

All above are correct

18) The transmission of the first eight pulse must be accurate and consistent since an error in indexing of one cycle would give a Report

8 us time difference error

6 us time difference error

10 us time difference error

19) LORAN C antenna can also be used for Report

ADF sense

As in (i) and antenna coupler is used for impedance matching

As in (ii) and also isolation for two receiver

20) The purpose of phase decode circuits Report

To separate master

To separate master and slave

To reverse the RF phase

EASA Questions Radio Nav. Set 3

Set 1

Set 2

Set 3

Set 4

Set 5

Set 6

Set 7