CDCs RF Transmission Systems 3d153 Self-Test Questions Volume III Unit III

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CDCs RF Transmission Systems

Created Apr 4, 2012
by richarddjames

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	Side A	Side B
1	413. Space segment 1. What is the purpose of the space segment?	4131. To provide the downlink information encompassing an area of coverage required by the...
2	2. Define telemetry?	2. The science of measuring physical properties and other phenomena onboard mission satellites...
3	3. What types of information do the telemetry, tracking, and command status contain?	3. Data on the receiver and demodulator units, command decryptor unit, downlink transmitter,...
4	4. What are the two major sections of a basic satellite?	4. (1) The mission (or missions) payload.(2) The spacecraft bus.
5	5. Why is stability important to the satellite?	5. Because it allows the payload to operate with accuracy and the satellite bus to receive...
6	6. For what types of satellites are position and orientation control especially critical?	6. Those using highly directional antennas.
7	414. Command and control segment 1. What is the function of the C2 segment?	4141. To support the satellites and enhance the downlinked mission data for the user segment.
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9	2. What do all satellites require, regardless of the program?	2. Telemetry, tracking and commanding support.
10	3. What is the purpose of antenna pointing data?	3. It is used to drive motors to move the antenna to the specific acquisition angles.
11	4. Why is satellite command verification so important?	4. To make sure commands have been executed properly.
12	5. Why is using the same reference time between the C2 segment and the satellite so important?...	5. Without it, operations—such as commanding mission satellites, processing and evaluating...
13	415. User segment 1. What is the purpose of the user segment?	4151. To receive, process, use, or distribute mission data as required by program taskings.
14	2. What is the purpose of the DMSP user segment?	2. To receive, process, and distribute global weather data to support Air Force, Army, Navy,...
15	3. In the DSP program, what agency operates SBIRS satellites?	3. The 460th Space Wing at Buckley AFB, Colorado.
16	4. Where do the DSP early warning centers forward their data?	4. To various agencies and operation areas around the world, varying with the Air Force’s...
17	5. What is the purpose of the GPS user segment?	5. To enable users to passively receive the satellite broadcast position, velocity, and time...
18	6. What is the primary purpose of Milstar?	6. To support the National Command Authority and provide the Navy, Army, and Air Force withinteroperable...
19	416. Acquisition and tracking principles 1. For what purposes do we use a satellite beacon?...	4161. To locate, identify, and track a satellite.
20	2. How does telemetry differ from the satellite beacons?	2. Telemetry refers to the data sent by the satellite to give on-board equipment status.
21	3. What is ephemeris data?	3. Data showing the calculated positions of a satellite at regular intervals of time.
22	4. How does computer programmed tracking differ from automatic signal tracking?	4. In computer programmed tracking, the position of the satellite is computed and the pointing...
23	5. Which autotracking method cannot sense the satellite location without moving off the satellite...	5. Random step track.
24	417. Earth terminal functional description1. What two IF frequencies are used by the DSCS earth...	4171. (1) 70 MHz at –10 dBm.(2) 700 MHz at –13 dBm.
25	2. How are the HPAs cooled in a DSCS earth terminal?	2. Air cooled.
26	3. What’s the downlink frequency range of a DSCS earth terminal?	3. 7.25 to 7.75 GHz.
27	4. What’s the size of an AN/GSC–52 antenna reflector, and what are the azimuth and elevationlimitations?	4. 38-foot dish, ±174 degrees in AZ and from –1 to 92.5 degrees in EL.
28	5. How many feedhorns does a AN/GSC–52 terminal use to determine tracking errors?	5. Four.
29	6. Which downconverter is designated as the tracking downconverter?	6. Downconverter 1 in Downconverter Rack 1.
30	7. What’s the purpose of the memory-tracking mode in a DSCS earth terminal?	7. Maintains a 24-hour record of antenna movements by the memory track unit. This data can...
31	8. What type of frequency standard is used in a DSCS earth terminal and what are its outputs?	8. Cesium. 5 MHz, 1 MHz, and 1 pps.
32	9. How does the operator control the AN/GSC–52 terminal?	9. Locally by the TP or RTP, or remotely by an ECE or the laptop from any of the terminal access...
33	418. Major equipment groups1. What feedhorns are in the AN/GSC–52 feedhorn assembly?	4181. One center sum (communication) feedhorn and four peripheral error (tracking) feedhorns.
34	2. The AIA develops AZ and EL tracking error signals. What is done with those signals?	2. The tracking-error data from the AIA is sent to TS-B and is used to create antenna velocity...
35	3. What type of HPA does the AN/GSC–52 use?	3. Traveling wave tube.
36	4. How many HPAs are normally operating at one time?	4. Three are active online, and one is in standby mode.
37	5. What happens if one of the AN/GSC–52 converters fails?	5. TS-A commands the appropriate switch assembly (DSA or USA) to automatically switch from...
38	6. Which converter (up or down) is normally dedicated to auto-switchover?	6. Number 8 in each rack.
39	7. What is the purpose of the FTS?	7. To generate and distribute precise 1 MHz and 5 MHz reference frequencies and 1 pps timing...
40	8. What is the purpose of the terminal servers?	8. To serve as interfaces to separate individual subsystems within the equipment complex. Each...
41	9. What can the terminal operator do with the terminal processor?	9. Manually configure the terminal equipment that will be online for any given operational...