DME

Question 1

DME measures the difference between __ pulses being sent from an aircraft and received back, on different frequencies

Answer 1

paired

Question 2

The aircraft is the first to transmit on _HF, when the DME transponder on the ground returns the signal after a __ microsecond delay.

Answer 2

UHF 50

Question 3

The 50 microsecond delay exists to reduce the chances of uncoordinated activity when the interrogating aircraft is ___ the station

Answer 3

near

Question 4

If the DME is part of an ILS installation, the delay is (not) present

Answer 4

not

Question 5

The pulses are . miliseconds wide

Answer 5

3.5

Question 6

___ frequencies are used, otherwise the first pulse received would be the ground return from below.

Answer 6

Two

Question 7

___, the deliberate random variation of the time interval between interrogations, is used to identify pulses

Answer 7

Jittering

Question 8

Only signals with the same jittering pattern, which is the ___, are replied to.

Answer 8

PRF

Question 9

DME is _HF based, between __ and ___ _Hz

Answer 9

960 1215 MHz

Question 10

___ pulse pairs are those which the beacon transmits even without interrogation

Answer 10

Squitter

Question 11

Signal discrimination depends on the ___ ___ and ___ spacing.

Answer 11

frequency separation, pulse

Question 12

The DME ident is pitched ___er than that of a VOR, at ___ _z

Answer 12

higher 1350 Hz

Question 13

The groundspeed readout ___ at an increasing rate when overflying an overhead the beacon

Answer 13

reduces

Question 14

The slant range is calculated by ___, remembering to subtract the __ delay at the transponder

Answer 14

Time / 12.4, 50

Question 15

Normally, __ pulse pairs are transmitted per second, going up to ___ for searching

Answer 15

30 150

Question 16

Up to ___ aircraft can interrogate the system before beacon saturation occurs.

Answer 16

100

Question 17

The ground station can only cope with ___ pps

Answer 17

2700

Question 18

DME wavelengths are ___

Answer 18

decimetric

Question 19

The design requirements for DME-P stipulates that the total system error should not exceed . NM

Answer 19

0.2

Question 20

If an interruption is caused, the airborne equipment is switched to memory mode for about __ seconds, with no signal received after that, the ___ flag appears

Answer 20

10 off

Question 21

The ___ ____ ____ circuit creates a __ microsecond delay on the transponder in order to allow enough time after the receipt of the interrogation pulse for any other reflected multipath echoes to arrive at the station and be ignored

Answer 21

Echo Protection Circuit

Question 22

DME airborne interrogation is made on one of ___ channels, at _ _Hz spacing between ___ and ___ _Hz

Answer 22

126 1 MHz 1025 and 1150 MHz

Question 23

UHF propagation methods are ___ or ___ waves

Answer 23

direct space

Question 24

The interrogation by the DME receiver does not start before ___ ___ of the tuned DME station are received

Answer 24

pulse pairs