Term
| 401-1. State the types of traffic an AN/TRC–170 radio terminal set might handle. |
|
Definition
Dedicated traffic such as analog and digital channels, point-to-point circuits, facsimile circuits, and teletype
circuits. |
|
|
Term
| 401-2. List the equipment included in an AN/TRC–170 tropospheric scatter terminal. |
|
Definition
Antennas, transmitting and receiving equipment, digital multiplexing equipment, voice and data orderwire
facilities, built-in test equipment, and communications security equipment. |
|
|
Term
| 401-3. List the data rates processed by the tropospheric scatter modem. |
|
Definition
Mission traffic at 128 through 4,096 Kbps in the 512 data rate family, and 72 through 4,608 Kbps in the
576 data rate family. |
|
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Term
| 401-4. Describe the upconversion process of the transmit amplifier. |
|
Definition
The IF signal is upconverted in the transmit amplifier converter by mixing it with a local oscillator input
from the synthesizers. The difference frequency is selected as the final transmit frequency of 4.4 to 5.0
GHz. |
|
|
Term
401-5. Explain the difference in the transmission power requirements between tropospheric scatter and
line-of-sight. |
|
Definition
The HPA is necessary for transmission in the tropospheric scatter mode (1 kW, 60 dBm). It is also possible
to transmit in LOS mode by not using the klystron. The output is 29 dBm (800 mW). |
|
|
Term
401-6. What is the minimum spacing used to separate receive antennas in space diversity, and what is the
most common amount of antenna separation used? |
|
Definition
| Minimum of 50 wavelengths; common receive antenna spacing is 100 or more wavelengths. |
|
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Term
| 401-7. What principle of propagation does frequency diversity use to its advantage? |
|
Definition
Frequency diversity uses the principle that two different microwave frequencies fade independently of each
other even though they travel the same propagation path. |
|
|
Term
| 401-8. What is the ideal frequency separation in frequency diversity? |
|
Definition
| A separation of 5 percent is ideal. |
|
|
Term
| 401-9. Define polarization diversity. |
|
Definition
In polarization diversity, the same frequency radiates simultaneously in two different planes: horizontal and
vertical. |
|
|
Term
| 401-10. Explain quadruple diversity. |
|
Definition
Quadruple diversity is a technique that employs a combination of two or more of the diversity types: a
combination of frequency and space diversity or space and polarization diversity—or a system that uses
four reception paths. |
|
|
Term
| 401-11. Explain the purpose of the digital data group modem. |
|
Definition
It interfaces up to four groups of conditioned diphase signals, or up to four groups of dipulse signals, or a
mixture of the two. |
|
|
Term
| 401-12. Describe the main purpose of the digital data group modem. |
|
Definition
Primarily, it changes cable-side conditioned diphase or dipulse signals to balanced NRZ signals, and vice
versa. |
|
|
Term
| 401-13. Describe the purpose of the low-speed cable driver modem. |
|
Definition
Changes the cable-side conditioned diphase signal to NRZ for use by the AN/TRC–170 and supplies power
to cable low-speed pulse restorers if required. |
|
|
Term
| 401-14. What data rates are used by the low-speed cable driver modem? |
|
Definition
| It accepts data at 72 to 2,048 Kbps on the equipment side; 2,304 Kbps on the cable side. |
|
|
Term
| 401-15. What is the range of the low-speed cable driver modem with and without pulse restorers? |
|
Definition
| Up to 40 miles with pulse restorers and 1 mile without pulse restorers. |
|
|
Term
| 401-16. Describe the capabilities of the trunk group multiplexer. |
|
Definition
It multiplexes up to four groups of the 512 Kbps data rate families or four groups of 576 Kbps data rate
families into one supergroup. It will not process group data rates from both families simultaneously. It
demultiplexes a supergroup into separate groups at their original data rates. It can control a KG–81 trunk
encryption device on both the group and supergroup side. |
|
|
Term
| 401-17. Describe the purpose of the KG–81 trunk encryption device. |
|
Definition
| Full-duplex encryption and/or decryption of group or supergroup mission traffic. |
|
|
Term
401-18. Describe the purpose of the KG–84 dedicated loop encryption device and the KG–84A general
purpose encryption equipment. |
|
Definition
| Encrypts and/or decrypts telemetry data, processed through the alarm monitor. |
|
|
Term
| 401-19. Describe the purpose of the KY–58 VINSON. |
|
Definition
Encrypts and/or decrypts digital voice orderwire traffic originating and terminating at the voice orderwire
control unit. |
|
|
Term
| 401-20. What is the purpose of the baseband patch panel? |
|
Definition
| Connects the digital group multiplex equipment with the tropospheric scatter modem. |
|
|
Term
| 401-21. Describe the three divided fields of the baseband patch panel. |
|
Definition
(1) The upper jack field provides timing and data connections for the trunk group multiplexer,
tropospheric scatter modem, and trunk encryption device 1. The right side provides patching for black
station clock. Also provided are convenience patch groups A, B, and C, that are internally hard-wired
to jacks in the center jack field.
(2) The center jack field provides connections to the equipment side of the loop group multiplexers,
group modem groups, and the low-speed cable driver modem. The black side of the trunk encryption
device 2 is also available. The dejitterizer input and/or output jacks provide for patching a group
timingsignal directly into the tropospheric scatter modem. Inputs to trunk group multiplexer groups 3
and 4are available. Convenience patch groups A, B, and C pass data and timing signals to the upper
jackfield.
(3) The lower jack field provides data orderwire connections for through patching or patching to and/or
from the dedicated loop encryption device patch panel by way of the level converter jacks. Also
provided are connections for the digital voice orderwire and resync commands to the group and super
group trunk encryption devices. |
|
|
Term
| 401-22. Describe the purpose of the dedicated loop encryption device patch panel. |
|
Definition
Provides for patching the local telemetry signals to the radio and/or cable side of the AN/TRC–170 and for
monitoring baseband and dedicated loop encryption device patch panel activity. |
|
|
Term
| 401-23. Describe the data rates of the tropospheric scatter modem. |
|
Definition
128 through 4,096 Kbps in the 512 data rate family and 72 through 4,608 Kbps in the 576 Kbps data rate
family. |
|
|
Term
| 401-24. List the types of inputs to the tropospheric scatter modem. |
|
Definition
| Mission data, digital voice orderwire, and up to four data orderwires. |
|
|
Term
| 401-25. What is the purpose of the loop back circuit in the IF patch panel? |
|
Definition
Provides a calibrated means of applying the tropospheric scatter modem modulator IF output to
tropospheric scatter modem demodulator inputs. |
|
|
Term
401-26. Why are the IF patch panels between the AN/TRC–170 V2 and V3 terminals not
interchangeable? |
|
Definition
| The IF test panels are configured differently for each terminal. |
|
|
Term
| 401-27. Describe the outputs of the electrical frequency synthesizer. |
|
Definition
| Stable outputs in the 4.47 to 5.07 GHz range. |
|
|
Term
| 401-28. List the major subassemblies of the RF HPA and state their purpose. |
|
Definition
(1) The microwave subassembly consists of a klystron amplifier, tuning, and built-in test equipment
circuitry. The klystron is a continuous-wave, HPA that is air-cooled and mechanically tunable. It is
bypassed, and the high voltage power supply is not used when operating in the LOS mode.
(2) The high voltage power supply provides beam and filament voltages for the klystron.
(3) The diplexer enables the transmitter and a receiver to operate from a common antenna port. The
diplexers are used in the V2 model only. |
|
|
Term
| 401-29. Describe the purpose of the downconverters. |
|
Definition
They preselect, amplify, and postselect the received microwave signal. The LNA and mixer combine the
4.4 to 5.0 GHz receive signal with a 4.47 to 5.07 GHz signal from the synthesizer to produce the 70 MHz
IF. |
|
|
Term
| 401-30. How does the alarm monitor determine overall system performance? |
|
Definition
Equipment status information and performance data from all major components are reported to the alarm
monitor by the built-in test equipment circuits in each major subassembly. The data is sampled, processed,
and evaluated. From this, overall system performance is determined. |
|
|
Term
| 401-31. List the orderwires and orderwire control units and describe each. |
|
Definition
(1) The data orderwire consists of a 20-character telemetry status message that can be combined with a
12-telemetry status message from other stations to form a 2 Kbps composite bit stream that is
transmitted to the communication nodal control element.
(2) The voice orderwire control unit connects a VINSON secure voice instrument with the 16 Kbps
digital voice orderwire. This is a first-come, first-served party line system. The unit’s electronic
bridge provides a through connection between the group modems and low-speed cable driver modem
or tropospheric scatter modem.
(3) The remote orderwire control unit accesses the digital voice orderwire through the voice orderwire
control unit. It does not provide secure voice transmission to the voice orderwire control unit.
(4) The analog voice orderwire (the maintenance orderwire) provides unencrypted, full-duplex voice
connection with analog voice orderwire channels of the group modem and low-speed cable driver
modem. It does not connect to the radio side of the AN/TRC–170 terminal. |
|
|
Term
| 401-32. What else does the power entry panel provide power to besides the equipment in the van? |
|
Definition
The environmental control unit, an external convenience outlet, antenna feedhorn deicers, as well to as an
external main breaker that controls the entire panel. |
|
|
Term
401-33. Describe how a surge protection circuit is used and whether it is required for an AN/TRC–170
terminal. |
|
Definition
It is placed across each phase and the neutral line. It is not required for the van to operate, but without it
there is no prime power surge protection. |
|
|
Term
| 401-34. List the functions of the power distribution unit. |
|
Definition
It provides a central location to control equipment using primary power for fast power-up and power-down.
It also powers the utility and convenience outlets and ceiling lighting. The front panel meters indicate
current, voltage, and frequency. |
|
|
Term
| 401-35. Describe the purpose of the AC-AC converters. |
|
Definition
They change the incoming AC signal to a 255 Vpp, 400 Hz quasi-square wave in order to operate the
cooling fans in the shelter. AC-AC converter 1 runs all the blowers in the van, except those in RF HPA#2,
these are run by AC-AC converter 2. |
|
|
Term
| 401-36. List the components and describe the function of the lightning protection assembly. |
|
Definition
It consists of two, four-section telescoping masts approximately 30 feet tall (assembled), a sky wire 135 feet
long, six anchors, two ground rods, and two mast base plates. The masts are installed 65 feet apart and
slightly behind the two antennas. The sky wire is suspended between the two masts and is grounded on both
ends. The lightning protection assembly acts as a large lightning rod by being the highest point at your
station. |
|
|
Term
| 402-1. Describe the RF output power and frequency band of the TSSR. |
|
Definition
| 14.4 to 15.25 GHz with RF output power of about 300 mW. |
|
|
Term
| 402-2. What are the two TSSR antenna lengths, and what are their maximum ranges? |
|
Definition
| 1 foot and 2 feet; 10 and 25 miles respectively. |
|
|
Term
| 402-3. List the TSSR conditioned diphase waveform voltage and data rate. |
|
Definition
| 3 Vpp conditioned diphase waveform ranging from 72 to 4,608 Kbps. |
|
|
Term
402-4. What is the maximum distance the TSSR’s RF and baseband assembly can be physically
separated from each other, using the supplied cable? |
|
Definition
|
|
Term
| 402-5. What is the gain of the TSSR’s 1-foot antenna? |
|
Definition
|
|
Term
| 402-6. What is the gain of the TSSR’s 2-foot antenna? |
|
Definition
|
|
Term
| 402-7. What is the purpose of the input attenuator in the TSSR’s transmit baseband assembly? |
|
Definition
| Compensates for input signal amplitude variations caused by external equipment or varying cable lengths |
|
|
Term
| 402-8. What is the transmitter deviation in the TSSR’s transmit baseband assembly? |
|
Definition
|
|
Term
402-9. What is the frequency of the transmitter subcarrier (orderwire) in the TSSR’s transmit baseband
assembly? |
|
Definition
|
|
Term
| 402-10. Describe the function of the TSSR’s diplexer. |
|
Definition
It allows the use of a single piece of coaxial cable to pass the transmitter baseband signal from the baseband
assembly to the RF assembly. Also transmitted on the same cable is the receiver 70 MHz IF signal from the
RF assembly to the baseband assembly. |
|
|
Term
402-11. In the TSSR’s RF assembly, what is the frequency of the voltage-controlled oscillator, and how is
its accuracy maintained? |
|
Definition
| 7 GHz; by a phase-locked loop |
|
|
Term
| 402-12. What is the purpose of the circulator in the TSSR’s RF assembly? |
|
Definition
| Permits the transmitter and receiver to be connected to the same antenna. |
|
|
Term
| 402-13. In the TSSR’s RF assembly, at what frequency is the tunable filter set? |
|
Definition
|
|
Term
402-14. How is noise generated by the transmitter prevented from interfering with the receiver, in the
TSSR’s RF assembly? |
|
Definition
The combination of tunable filter and three-port circulator is used to form a notch filter. The notch filter is
tuned to the receiver’s frequency to reduce any noise generated by the transmitter that could interfere with
the receiver. |
|
|
Term
| 402-15. Describe the frequency conversion process in the TSSR’s receive section. |
|
Definition
The 14.4 to 15.25 GHz RF is mixed with the local oscillator frequency to produce a 70 MHz IF. The local
oscillator frequency is always on the low side of the signal; that is, the local oscillator frequency equals the
signal frequency minus 70 MHz. |
|
|
Term
402-16. What is the bandpass frequency range of the 70 MHz IF in the TSSR’s control and distribution
unit? |
|
Definition
|
|
Term
402-17. Which unit compensates for changes in the interconnecting cable length in the TSSR’s receive
baseband assembly? |
|
Definition
| Automatic gain control amplifier |
|
|
Term
402-18. In the TSSR’s receive baseband assembly, what type of waveform and data rate is used when
operating in the fiber optic mode? |
|
Definition
| NRZ digital signals at a 6.144 Mbps rate |
|
|
Term
| 402-19. What type of orderwire capability does the TSSR provide? |
|
Definition
| Full-duplex voice communication |
|
|
