UHF C3 Flashcards Preview

ACOM/IFT CAT 1 > UHF C3 > Flashcards

Flashcards in UHF C3 Deck (47):
1

What is the purpose of the UHF C3 Radio subsystem?

high-power, Line-of-Sight (LOS) airborne communications of voice & data

2

What is the frequency range of the UHF C3 Radio subsystem?

225.000 - 399.975 MHz

3

How many UHF C3 Antennae are there?

5
3 TX, 2 RX

4

Where are the UHF C3 Antennae located?

TX (1) - top FS 470; TX (2) - bottom FS470;
TX (3) - bottom FS 570; RX (4) - FS1150;
RX (5) - top/fwd of VLF/LF RX Antenna

5

What are the power requirements for the UHF C3 Antennae?

Passive

6

What is the function of the UHF C3 Antennae?

TX & RX voice & data; provide a nominal RF impedance of 50 Ohms over a 225 - 399.975 MHz frequency range; handle RF power of up to 1,500 W

7

Where are the UHF Control Panels located and how many are there?

2
P30 Bays 1& 2

8

What are the power requirements for the UHF Control Panels?

28 VDC from CONT 1 & 2 c/bs on P30 DISTR 2

9

What is the function of the UHF Control Panels?

to select and control individual RF, operating mode, and R/T output power

10

How many frequencies are selectable via the UHF Control Panels?

20 preset frequencies or 7,000 manual frequencies between 225.000 & 399.975 MHz selectable in 25 KHz increments

11

What are the 3 operating modes selectable via the UHF Control Panels?

Wideband Frequency modulated (WBFM) - Data
Narrowband Frequency Modulated (NBFM) - Data
Narrowband Amplitude Modulated (NBAM) - Voice

12

Where is the Auxiliary Control Panel (UHF C3 Aux Control Panel) located?

P30 Bay 2

13

What are the power requirements for the UHF C3 Aux Control Panel?

28 VDC from AUX CONT c/b on P30 DISTR 2

14

What is the function of the UHF C3 Aux Control Panel?

provide primary input power, associated equipment selection, control, and indications for UHF C3;
ON/OFF to HPA power supplies; momentary reset of DAISS; indicate link alarms for DAISS; upper & lower RX Antenna selection; selection of UHF Control 1 or 2

15

Where is the UHF C3 Mode Select Panel located?

P30 Bay 2

16

What are the power requirements for the UHF C3 Mode Select Panel?

28 VDC from MODE SEL c/b on P30 DISTR 2

17

What is the function of the UHF C3 Mode Select Panel?

provide the switching controls necessary to select which system will interface with the UHF C3 radios

18

Where is the Baseband Control Assembly (BCA) located?

C2 cabinet above the UHF C3 HPAs

19

What are the power requirements for the Baseband Control Assembly (BCA)?

28 VDC from BASE BAND CONT c/b on E60-2

20

What is the function of the Baseband Control Assebmly (BCA)?

monitors & conditions baseband noise & modem automatic gain control levels to provide discrete signal control over BCA squelching circuitry;
patching capability

21

Where is the UHF C3 Power Meter located?

P30 Bay 4, above MCS Display

22

What are the power requirements for the UHF C3 Power Meter?

Passive

23

What is the function of the UHF C3 Power Meter?

indicate forward power (F) or reflected power (R) for selected UHF C3 radio (1, 2, or 3)

24

Each power sensor for the UHF C3 Power Meter contains ____?

2,500 W sensor element for measuring Forward
500 W sensor element for measuring Reflected

25

Where are the UHF C3 R/Ts located and how many are there?

3 total
C2 cabinet

26

What are the power requirements for the UHF C3 R/Ts?

115 VAC 400 Hz from R/T 1, 2, & 3 c/bs on E60-2

27

What is the function of the UHF C3 R/Ts?

translate received RF signal to a 70 MHz Intermediate Frequency (IF) and send it to the Modems for demodulation; translate 70 MHz IF from Modem to selected UHF frequency, amplify, filter, & rout it to HPAs for TX

28

Where is the 70 MHz Select Switch located?

C2 cabinet

29

What are the power requirements for the 70 MHz Select Switch?

28 VDC from MODE SEL c/b on P30 DISTR 2;
functions with Mode Select Panel

30

What is the function of the 70 MHz Select Switch?

to interface the UHF C3 with ALCS;
operate in response to Mode Select Panel, electronically selecting the UHF C3 receiver's 70 MHz auxiliary channel to be used for the ALCS

31

Where are the UHF C3 HPAs located and how many are there?

3 total
C2 cabinet

32

What are the power requirements for the UHF C3 HPAs?

115 VAC 400 Hz from HPA 1, 2, & 3 on E60-2

33

What is the function of the UHF C3 HPAs?

deliver 1 KW over a 225.000 - 399.975 MHz frequency range into a 50 Ohm load; amplify TX signal to supply RF power to an unassociated TX antenna

34

The UHF C3 HPAs amplify TX signal to supply ______ or ______ of RF power to an unassociated UHF C3 TX Antenna.

250 W (AM);
1000 W (FM)

35

Where are the UHF C3 Modems located and how many are there?

3 total
C2 cabinet

36

What are the power requirements for the UHF C3 Modems?

115 VAC 400 Hz from MODEM 1, 2, & 3 c/bs on E60-2
28 VDC from MODEM 1, 2, & 3 c/bs on E60-2

37

What is the function of the UHF C3 Modems?

interface with the UHF Control Panels;
provide radio power ON/OFF, tuning, R/T enable, self-test, fault detection, and mode of operation

38

Where is the UHF C3 Multicoupler/Receive Bandpass Filters located?

Rear of P20 Bay 1

39

What are the power requirements for the UHF C3 Multicoupler/Receive Bandpass Filters?

28 VDC from RCVR FLTR 1, 2, & 3 c/bs on P20 DISTR 1A

40

What is the function of the UHF C3 Multicoupler/Receive Bandpass Filters?

to receive 1 input signal and split it into 3 signals, allowing the use of a single RX antenna

41

The UHF C3 Multicoupler consists of 2 Bandpass Filters, one with a _____ bandpass for widebandsignals and the other with a _____ bandpass for narrowband signals.

291.8 - 298 MHz
314.9 - 400 MHz

42

Where are the UHF C3 Transmit Bandpass Filters located and how many are there?

3 total
C2 cabinet (top shelf)

43

What are the power requirements for the UHF C3 Transmit Bandpass Filters?

28 VDC from XMTR FLTR 1, 2, & 3 c/bs on E60-2

44

What is the function of the UHF C3 Transmit Bandpass Filters?

to take the transmit RF from the R/Ts and route it to the UHF C3 HPAs for amplification

45

Where is the UHF C3 Receive Preampfilter located?

Rear of P20 Bay 2

46

What are the power requirements for the UHF C3 Receive Preampfilter?

28 VDC from PRE AMP c/b on P20 DISTR 1A

47

What is the function of the UHF C3 Receive Preampfilter?

amplifies the received RF signals from each Receive Bandpass Filter before routing them to the R/Ts for the applicable receiver system