b.
In addition to conventional HF communications the radio provides automatic link establishment (ALE). In this mode each station has an address that identi.es it, instead of an assigned frequency. The radio automatically estab-lishes a 2 way communications link between stations on the best available frequency, and then noti.es the pilot that communications can begin. This raises the success rate for .rst try links to a distant station from 30 percent to 90 percent. This linking process may take up to 10 seconds, and will be performed after each pause in communications greater than 60 seconds. Electronic counter countermea-sures (ECCM), in the form of frequency hopping requires that radios have the same keys and be synchronized to the same time source. This radio uses the helicopter’s GPS as its time source. Both ALE protection and ECCM keys are loaded from the data transfer cartridge. ECCM keys control the frequency hopping pattern. ALE link protection keys encode station address information to prevent an unautho-rized station entry in the net.
c.
Power for the radio is provided from the No. 1 dc primary bus through a circuit breaker marked HF.
3.9.1 Antenna. The tubular antenna element is routed from the left side of the transition area to a point just for-ward of the hinged tailcone section, and is supported by four masts. RF energy is supplied to the antenna via the forward mast (Figure 3-1).
3.9.2 Controls and Functions. The AN/ARC-220 ra-dio is controlled by the AMS with the CDU (Figure 3-2). Control screens allow the pilot to choose frequency and mode of transmission (Figure 3-14). The AN/ARC-220 is referred to as COM 5, which corresponding to its position on the ICS mode select switch. Operator functions are to change band, transmission frequency and mode, and edit and establish preset modes and frequencies. Bands associ-ated with this radio are:
BAND FIELD BAND NAME FREQUENCY RANGE
HF-LSB HF Lower Side 2.0000 to
Band 29.9999
HF-USB HF Upper Side 2.0000 to
Band 29.9999
HF-AM HF AM 2.0000 to
29.9999
HF-MRN HF AM Marine CHN:0401 to
CHN:2510
with gaps.
ALE-ECM ALE-ECCM 2.0000 to
29.9999
3.9.2.1 COM Summary Screen. The COM SUM screen allows the operator to perform all primary radio con-trols. SK-6 selects COM 5 settings for editing.
SOFT KEY FUNCTION
SK-6s Selects and then toggles between COM 5 frequency and preset .eld for editing.
gLAST Restores the last manually tuned frequency, while saving the current settings. This function saves one setting per band of operation.
EMERGs Swaps current frequency with the band based guard frequency for radio that has been selected for edit.
KY-100g Access KY-100 screen.
3-34 Change 4
SOFT KEY FUNCTION
BANDg Access band selection screen for radio that has been selected for edit.
SETTINGSg Access settings screen for radio that has been selected for edit.
3.9.2.2 Band Screen. The current operating band is shown in inverse video. When the pilot pushes a soft key for a new mode, that mode is selected, and the screen re-turns to either the COM summary screen or the Setting screen previously in use.
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：UH-60Q 直升機技術手冊 直升機操作手冊 1(80)
