Questions

Questions 15

1.Airborne DME equipment is able to discriminate between pulses intended for itself and pulses intended for other aircraft because:

a.aircraft transmit and receive on different frequencies

b.aircraft will only accept unique twin pulses

c.aircraft reject pulses not synchronized with its own random pulse recurrence rate

d.each aircraft has its own frequency allocation

2.A DME beacon having a transmit frequency of 962 MHz would have a receive frequency of:

a.1030 Mhz

b.902 Mhz

c.1025 Mhz

d.962 Mhz

3.A VOR/DME share the same first two letters of their respective identifiers; the last identifying letter of the DME is a Z. This means that:

a.they are co-located

b.they are more than 600 m apart but serve the same location

c.they are widely separated and do not serve the same location

d.they are a maximum distance of 30 m apart

5.A DME transponder does not respond to pulses received from radars other than DME because:

a.each aircraft transmits pulses at a random rate

b.DME transmits and receives on different frequencies

c.it will only accept the unique twin DME pulses

d.DME only responds to the strongest 100 interrogators

6.The range indicated by DME is considered to be accurate to within:

a.3% of range

b.1.25 % of range

c.0.5 NM

d.+/-0.25 NM +/-1.25% of range

7.A DME receiver is able to distinguish between replies to its own interrogations and replies to other aircraft because:

a.DME is secondary radar and each aircraft transmits and receives on a different frequency

b.DME transponders reply to interrogations with twin pulses and the airborne equipment ejects all other pulses

c.each aircraft transmits pulses at a random rate and will only accept synchronized replies

d.when DME is in the search mode it will only accept pulses giving the correct range

8.When a DME transponder becomes saturated:

a.it reverts to standby

b.it increases the number of pulse pairs to meet the demand

c.it increases the receiver threshold to remove weaker signals

d.it goes into a selective response mode of operation

9.An aircraft flying at FL250 wishes to interrogate a DME beacon situated 400 ft AMSL. What is the maximum range likely to be achieved?

a.210 NM

b.198 NM

c.175 NM

d.222 NM

10.For a DME and a VOR to be said to be associated it is necessary for: b. the DME to transmit on the same VHF frequency as the VOR

b.the aerial separation not to exceed 100 ft in a TMA or 2000 ft outside a TMA

c.the aerial separation not to exceed 100 m in a TMA or 2000 m outside a TMA

d.both beacons to have the same first two letters for their ident but the last letter of the DME to be a ‘Z’

11.The transmission frequency of a DME beacon is 63 MHz removed from the aircraft interrogator frequency to prevent:

a.interference from other radars

b.the airborne receiver locking on to primary returns from its own transmissions

c.static interference

d.receiver accepting replies intended for other interrogators

12.The accuracy associated with DME is:

a.+ or - 3% of range, or 0.5 NM, whichever is greater

b.+ or - 1.25% of range

c.+ or - 3% of range

d.+/-0.25 NM +/-1.25% of range

Questions 15