This standard specifies the calculation method of radio wave propagation loss and channel interference in high-frequency radio telephone communications of coastal stations, and specifies the minimum usable signal field strength of the coastal station receiving station in high-frequency radio telephone communications. This standard is applicable to coastal stations with operating frequencies in the range of 3~30MHz. GB/T 14856-1993 Calculation method of high-frequency radio telephone channel interference of coastal stations GB/T14856-1993 Standard download decompression password: www.bzxz.net

UDC654.165
National Standard of the People's Republic of China
GB/T 14856—93
Interference calculation methods of coast radiotelephone station operating in high frequency bands
Published on December 30, 1993
State Bureau of Technical Supervision
Implementation on September 1, 1994
National Standard of the People's Republic of China
Interference calculation methods of coast radiotelephone station operating in high frequency bands highfrequencybands
1 Subject content and scope of application
1.1 Subject content
GB/T14856-93
This standard specifies the calculation method of radio wave propagation loss and channel interference in high-frequency radio telephone communications of coast stations, and specifies the minimum usable signal field strength of coast station receiving stations in high-frequency radio telephone communications. 1.2 Scope of application
This standard applies to coast stations with operating frequencies in the range of 3 to 30 MHz. 2 Reference standards
GB11410
3 Terms
Technical regulations for shortwave broadcasting network coverage
3.1 Coast station coaststation
Land station in maritime mobile service.
3.2 High-frequency radiotelephone highfrequencyradiotelephone Single-sideband radiotelephone with operating frequencies between 3 and 30 MHz and operating modes of H3E, R3E, and J3E. 3.3 Minimum usable signal field strength minimum usable signal field strength The minimum value of signal field strength required to achieve the desired reception quality under specified reception conditions when there is natural interference and man-made noise but no interference from other transmitters. 3.4 Protection ratio protection ratio
In order to ensure that single-sideband radiotelephone communication achieves a certain call quality, the ratio of the minimum usable signal field strength to the interference signal field strength is in dB.
4 Calculation method of propagation loss
4.1 Calculation of basic transmission loss L for skywave propagation L = Loe + La + Y,
Where: L——basic skywave transmission loss, dB; Lor——basic free space transmission loss, dB, Approved by the State Administration of Technical Supervision on December 30, 1993 (1)
Implemented on September 1, 1994
La——ionospheric absorption loss, dB;
Y——extra system loss, dB.
GB/T14856—93
4.1.1 The calculation formula of the basic free space transmission loss L is: a. 1E mode
2D, sin
Lbe=32.45+201gf+201g
cos(AE+www.bzxz.net
Where: LpE
—1E mode basic free space transmission loss, dB; - operating frequency, MHz;
—earth radius, taken as 6370km,
D—the great circle distance between the receiving point and the transmitting point, km, AE—1E mode ray elevation angle, rad.
b. 1F mode
2D, si n
Lom=32.45+201gf+201g
-1F mode free space basic transmission loss, dB; where ·L
-1F mode ray elevation angle, rad.
4.1.1.1 Calculation of ray elevation angle △E, AF AE=tg
cOSAF+
(h'e+D).sin
ctg2D,
where: h——the height of the ionosphere E layer, taken as 110km; hr—the height of the ionosphere F layer, km.
(n'+D.)·sin2D.
（4）
（5）
If △E
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