# The Radio Spectrum for Beginners

I could never hope to fully describe the RF spectrum, but here are the more obvious large chunks. This page assumes you understand the basic prefixes:

1000 Hz  = 1 kHz
1000 kHz = 1 MHz = 1,000,000 Hz
1000 MHz = 1 GHz = 1,000,000 kHz

You sometimes see the wavelength instead of the frequency. The speed of light is
c = 300,000,000 meters/second
So, the wavelength in meters is 300 divided by the frequency in MHz.
Higher frequency —> shorter wavelength
Lower frequency —> longer wavelength

Names were assigned to broad ranges of frequencies starting at the birth of radio. What was a very high frequency for the equipment of the 1920s is not very high at all. So the "short-wave" bands at (roughly) 3-30 MHz are, by today's standards, actually quite long waves! But we're stuck with the names — the terms commonly used are:

 Name Frequency range Propagation ELF Extremely Low Frequency 3 – 30 kHz Generally very poor, although at very high power levels it will penetrate salt water and earth VLF Very Low Frequency 30 – 300 kHz Generally worthless in day, longer range at night at higher frequencies. Much atmospheric noise. LF Low Frequency 300 – 3000 kHz 0.3 – 3 MHz Absorbed by D layer of ionosphere during the day, continental coverage possible at night. HF High Frequency 3 – 30 MHz Refracts from F layers (F1 and F2) layers of ionosphere, world-wide coverage possible depending on frequency and ionospheric conditions (function of solar and geomagnetic activity) along the path. VHF Very High Frequency 30 – 300 MHz Generally line of sight out to tens or hundreds of kilometers. May be refracted by sporadic ionized clouds in E layer of ionosphere (called "sporadic-E" or "Es" propagation). Reflected by auroral curtains and ionized trails of meteorites. UHF Ultra High Frequency 300 – 3000 MHz 0.3 – 3 GHz Generally line of sight out to tens of kilometers. Reflected by auroral curtains and ionized trails of meteorites. Absorption by atmospheric water by limited bands of frequencies starts at the upper end of this range (microwave ovens, at 2.4-2.5 GHz, use this phenomenon to heat food).

Above about 1 GHz you tend to see "microwave" used as a general term.

## ELF, VLF, and LF through the Medium-Wave Broadcast Band

Remember that these are just very rough listings, and in some cases they are U.S.-specific!

 Frequencies, kHz Uses 0.030 – 0.090 US and Russian communications with submarines. Very low bandwidth (data rate), but these frequencies do propagate down into salt water. The U.S. system operates at 76 Hz, the Russian one at 82 Hz. 10 – 60 Long-range navigation signals, time signals 150 – 175 US DOD GWEN (Ground Wave Emergency Network) 250 – 530 Aviation navigation beacons 530 – 1700 AM broadcast 10 kHz channel spacing in North America, 9 kHz worldwide

## The HF Bands — 1.7 - 30 MHz

The HF or "short-wave" bands, further divided into many uses:

1.800 -  2.000 Amateur 160m band
2.000 -  2.107 Maritime
2.107 -  2.170 Fixed
2.170 -  2.194 Maritime
2.197 -  2.300 Fixed
2.300 -  2.495 Broadcast 120m band
2.495 -  2.840 Fixed
2.840 -  3.155 Aeronautical
3.155 -  3.200 Fixed
3.200 -  3.400 Broadcast 90m band
3.400 -  3.500 Aeronautical
3.500 -  3.900 Amateur 80m band
3.900 -  4.000 Amateur 80m band+ Broadcast 75m band
4.000 -  4.438 Maritime
4.438 -  4.650 Fixed
4.650 -  4.750 Aeronautical
4.750 -  5.060 Broadcast 60m band
5.060 -  5.450 Fixed
5.450 -  5.730 Aeronautical
5.730 -  5.950 Fixed
5.950 -  6.200 Broadcast 49m band
6.200 -  6.525 Maritime
6.525 -  6.765 Aeronautical
6.765 -  7.000 Fixed
7.000 -  7.200 Amateur 40m band
7.200 -  7.300 Amateur 40m band+ Broadcast 41m band
7.300 -  7.450 Broadcast 41m band
7.450 -  8.100 Fixed
8.100 -  8.815 Maritime
8.815 -  9.040 Aeronautical
9.040 -  9.400 Fixed
9.400 -  9.900 Broadcast 31m band
9.900 -  9.995 Fixed
9.995 - 10.005 Time and frequency standards
10.005 - 10.100 Aeronautical
10.100 - 10.150 Amateur 30m band + Fixed
10.150 - 11.175 Fixed
11.175 - 11.400 Aeronautical
11.400 - 11.600 Fixed
11.600 - 12.100 Broadcast 25m band
12.100 - 12.230 Fixed
12.230 - 13.200 Maritime
13.200 - 13.360 Aeronautical
13.410 - 13.570 Fixed
13.570 - 13.870 Broadcast 22m band
13.870 - 14.000 Fixed
14.000 - 14.350 Amateur 20m band
14.350 - 14.990 Fixed
14.990 - 15.010 Time and frequency standards
15.010 - 15.100 Fixed
15.100 - 15.800 Broadcast 19m band
15.800 - 16.360 Fixed
16.360 - 17.410 Maritime
17.410 - 17.480 Fixed
17.480 - 17.900 Broadcast 16m band
17.900 - 18.030 Aeronautical
18.030 - 18.068 Fixed
18.068 - 18.168 Amateur 17m band
18.168 - 18.780 Fixed
18.780 - 18.900 Maritime
18.900 - 19.020 Broadcast 15m band
19.020 - 19.680 Fixed
19.680 - 19.800 Maritime
19.800 - 21.000 Fixed
21.000 - 21.450 Amateur 15m band
21.450 - 21.850 Broadcast 13m band
21.850 - 21.924 Fixed
21.924 - 22.000 Aeronautical
22.000 - 22.855 Maritime
22.855 - 23.200 Fixed
23.200 - 23.350 Aeronautical
23.350 - 24.890 Fixed
24.890 - 24.990 Amateur 12m band
24.990 - 25.670
25.670 - 26.100 Broadcast 12m band
26.100 - 26.175 Maritime
26.175 - 26.480 Land mobile
26.480 - 26.950 Government
26.950 - 27.410 "Citizen's band"
27.410 - 27.540 Land mobile
27.540 - 28.000
28.000 - 29.700 Amateur 10m band
29.700 - 29.800 Land mobile

## Microwaves — 1 GHz and Up

1.030 GHz     IFF / ATC radar beacon interrogate
1.1176        GPS L5 signal
1.242 - 1.249	GLONASS navsats L1 freq (FDMA)
1.2276        GPS L2 freq (spread-spectrum, below thermal noise floor)
1.240 - 1.300	Amateur radio (calling freqs = 1296.1 SSB/CW, 1294.5 FM)
1.400 - 1.427	Protected radio astronomy band (1.420 is H20 resonance)
1.5754        GPS L1 freq (spread-spectrum, below thermal noise floor)
1.5445        SARSAT, search and rescue, EPRIB emergency beacons
1.535 - 1.542	Intelsat comsat
1.598 - 1.606	GLONASS navsats L2 freq (FDMA)
1.616 - 1.627	Iridium LEO satellite telephones
1.626 - 1.646	EPRIB emergency beacons
1.660 - 1.670	Protected radio astronomy band (hydroxyl resonance)
1.691         GOES wefax imagery
1.694         ESA Meteosat
1.700 - 1.900	SDS recon platforms
1.710 - 1.880	GSM-1800 digital mobile telephones
1.850 - 1.910	Personal Communications Services (PCS), mobile
1.850 - 1.990	GSM-1900 digital mobile telephones
1.880 - 1.900	DECT (Digital European Cordless Telephone)
1.895 - 1.918	PHS (Personal Handy Phone System, cordless phone)
1.930 - 1.990	Personal Communications Services (PCS), base
2.206         SPOT recon platform
2.211         TDRS
2.280 - 2.304	Early warning network
2.204 - 2.400	Deep space probes
2.300 - 2.310	Amateur radio (calling freqs = 2304.1 SSB/CW, 2305.2 FM)
2.320 - 2.345	DARS, Digital Audio Radio via Satellite, audio to automobiles
2.402 - 2.484	Bluetooth data communication (FHSS)
2.410 - 2.484	802.11b, 802.11g wireless LAN (DSSS)
2.410 - 2.484	2.4 GHz cordless phones
2.450         Microwave ovens
2.450 - 2.500	ISM (Industrial, Scientific, Medical)
2.670 - 2.700	Protected radio astronomy band
2.840         H20 resonance
SHF----------------------------------------------------------------------------
3.700 - 4.195	C-band satellite TV, channels 1-24 on (3720 + 20*(chan-1)) MHz
4.950 - 5.000	Protected radio astronomy band
5.031 - 5.091	MLS (microwave landing system)
5.150 - 5.350	802.11a wireless LAN
5.725 - 5.825	802.11a wireless LAN (DSSS), 5.8 GHz cordless phones
5.725 - 5.875	ISM (Industrial, Scientific, Medical)
8.50 - 10.70	X-band radar (aviation WX 9.3 GHz, police 10.525 GHz)
10.00 - 10.50	Amateur radio (calling freq = 10.364 or 10.368)
10.45 - 10.60	X-band police radar
10.60 - 10.70	Protected radio astronomy band
10.90 - 11.75	Ku1-band satellite TV
11.75 - 12.50	Ku2-band satellite TV (11.7-12.2=Direct to Home, 12.2-12.7=DBS)
12.50 - 12.75	Ku3-band satellite TV (DBS)
15.35 - 15.40	Protected radio astronomy band
18.00 - 20.00	Ka-band satellite TV, North American channels 1-16
18.80 - 20.20	Iridium gateway downlinks
22.21 - 22.26	Protected radio astronomy band
24.00 - 24.25	Amateur radio (calling freq = 24.192 GHz)
24.00 - 24.25	ISM (Industrial, Scientific, Medical)
27.50 - 30.00	Iridium gateway uplinks
EHF----------------------------------------------------------------------------
33.40 - 36.00	Ka-band police radar
47.00 - 47.20	Amateur radio (SSB/CW calling freq = 47.040 GHz)
75.50 - 81.00	Amateur radio (SSB/CW calling freq = 80.640 GHz)
119.98 -120.02	Amateur radio (SSB/CW calling freq = 120.00 GHz)
142.00 -149.00	Amateur radio (SSB/CW calling freq = 144.00 GHz)
241.00 -250.00	Amateur radio (SSB/CW calling freq = 247.76 GHz)

Also see the frequency lists of UHF and microwave satellites at uhf-satcom.com.