Which of the following systems is most likely to be subject to fading or static interference?
A. HF NBDP
B. INMARSAT
C. Digital Selective Calling on channel 70
D. VHF ARQ
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What is the approximate range of VHF radio waves during the day time?
A. 30 nautical miles
B. 600 nautical miles
C. 150 nautical miles
D. 1200 nautical miles
下列选项是分拣工作特点的是()。
A. 工作标准高
B. 技术要求高
C. 质量要求高
D. 手续要求高
Under GMDSS, the proper functioning of the DSC facilities shall be tested periodically without radiation of signals, by use of the means provided by equipment. What is the period?
A. Weekly
B. Annually, by a representative of the MSA
C. Daily
D. Monthly
某工程的工艺管道安装完毕后,需要对管道内部进行吹扫,然后用15%盐酸溶液对管道内壁进行冲洗,确认合格后,对管道进行充氮保护。对工艺管线内壁表面所做的预处理属于()。
A. 手工除锈
B. 喷射除锈
C. 火焰除锈
D. 化学除锈