Allocations

 
U.S. Non-Federal-Government Allocations
21.85 - 21.924 MHz
FIXED


U.S. Federal Government Allocations
21.85 - 21.924 MHz
FIXED


ITU Region 1 Allocations
21.87 - 21.924 MHz
FIXED 5.155B


ITU Region 2 Allocations
21.87 - 21.924 MHz
FIXED 5.155B


ITU Region 3 Allocations
21.87 - 21.924 MHz
FIXED 5.155B


SpectrumWiki

Band Uses (21850 - 21924 kHz)

Footnotes

5.155B   The band 21 870-21 924 kHz is used by the fixed service for provision of services related to aircraft flight safety.

US340   The band 2-30 MHz is available on a non-interference basis to Federal and non-Federal maritime and aeronautical stations for the purposes of measuring the quality of reception on radio channels. See 47 CFR 87.149 for the list of protected frequencies and bands within this frequency range. Actual communications shall be limited to those frequencies specifically allocated to the maritime mobile and aeronautical mobile services.


SpectrumWiki

 
Shortwave Broadcasting
Access Broadband over Power Line (Access BPL)


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Engineering Data

Lower Frequency Center Frequency Upper Frequency
Frequency 21850 kHz 21887 kHz 21924 kHz
Wavelength 13.7 m 13.7 m 13.7 m
Band designator(s) HF HF HF
Isotropic collecting area 15.0 m2 14.9 m2 14.9 m2
Free space loss (1 m) N/A (near field) N/A (near field) N/A (near field)
Free space loss (1 km) 59.2 dB 59.3 dB 59.3 dB
Free space loss (10 km) 79.2 dB 79.3 dB 79.3 dB
Free space loss (100 km) 99.2 dB 99.3 dB 99.3 dB
Free space loss (1000 km) 119.2 dB 119.3 dB 119.3 dB
Free space loss
(35,786 km = GEO orbit)
150.3 dB 150.3 dB 150.3 dB
Free space loss (378,370 km = Moon) 170.8 dB 170.8 dB 170.8 dB
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