Dual-direction rhombic antenna switching network.

The Radio Spectrum for Beginners

The Radio Spectrum

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

VHF and UHF — 30 – 1000 MHz

MHz Use
30 — 50 "Low VHF" — longer-range VHF band used for two-way communications. construction companies, state police in US.
50 — 54 Amateur radio, 6m band.
54 — 72 VHF television broadcast channels 2, 3, 4
There was originally a channel 1 at 48-54 MHz, but it was at a low enough frequency that at many times, especially in sporadic-E season during the summer months, the signals propagated too far. Broadcast stations on channel 1 would interfere with each other even at great distances.
72 — 76 Industrial control links, aviation marker beacons, radio astronomy.
76 — 88 VHF television broadcast channels 5 & 6.
88 — 108 FM broadcast
200 kHz channel spacing in US: 88.1, 88.3, ...
108 — 118 Aviation navigation beacons.
118 — 137 Aviation communications.
137 — 138 Space to Earth.
144 — 148 Amateur radio, 2m band.
148 — 152 Satellites; Earth to space 148-150, satellite navigation 149.9-150.05.
152 — 162 "High VHF" — shorter-range (kilometers to tens of kilometers) two-way communications, and pagers.
Maritime mobile 157.0375-157.1875.
162 — 174 Government two-way communications, weather broadcasts (162-163 MHz), Lojack vehicle tracking/recovery.
174 — 216 VHF television broadcast channels 7-13.
216 — 225 Low-power health care, law enforcement tracking, maritime communications, radar, amateur radio (222-225 MHz).
225 — 420 Military aircraft and satellite links.
420 — 450 Amateur radio, 70cm band.
450 — 470 UHF two-way communications: business and government.
470 — 698 UHF television broadcast channels 14-51
698 — 806 "D Block" band designated by the FCC for a national public safety broadband data network.
764 — 869 APCO P25 (Association of Public-Safety Communication Officials, Project 25)
Public-safety two-way communications
824 — 894 IS-54 / IS-139 (North American Digital Cellular), digital mobile phones in North America, Asia, Australasia
Handsets 824-849 MHz, base stations 869-894 MHz
TDMA/FDM (Time-Domain Multiple Access / Frequency-Division Multiplexing)
IS-95 (North American Digital Cellular), digital mobile phones in North America, Asia, Australasia
Handsets 824-849 MHz, base stations 869-894 MHz
CDMA/FDM (Code-Division Multiple Access / Frequency-Division Multiplexing)
AMPS (Advanced Mobile Phone Service), old-style analog mobile telephones in the Americas and elsewhere
Handsets 824-849 MHz, base stations 869-894 MHz
FDMA (Frequency-Division Multiple Access)
Formerly US UHF television broadcast channels 73-83
860 — 949 TACS (Total Access Communications System), analog mobile telephones in Africa and Asia
ETACS: handsets 871-904 MHz, base stations 916-949 MHz
NTACS: handsets 915-925 MHz, base stations 860-870 MHz
FDMA (Frequency-Division Multiple Access)
860 — 960 RFID
864 / 868 CT2 (Cordless Telephone 2) digital cordless telephones
880 — 960 GSM (Global System for Mobile Communications), digital mobile telephones
Handsets 880-915 MHz, base stations 925-960 MHz
TDMA/FDM (Time-Domain Multiple Access / Frequency-Division Multiplexing)
885 / 932 CT1+ (Cordless Telephone 1) analog cordless telephones
890 — 960 NMT (Nordic Mobile Telephone), analog mobile telephones in Europe and Asia
Handsets 890-915 MHz, base stations 935-960 MHz
FDMA (Frequency-Division Multiple Access)
898 / 915 / 2400 ZigBee (IEEE 802.15.4) personal-area network
902 — 928 Radar, amateur radio 33cm band, industrial applications
914 / 960 CT1 (Cordless Telephone 1) analog cordless telephones
944 / 948 CT2+ (Cordless Telephone 2) digital cordless telephones

Microwaves — 1 GHz and Up

  1.030 GHz     IFF / ATC radar beacon interrogate
  1.090         IFF / ATC radar beacon reply
  1.1176        GPS L5 signal
  1.215 - 1.400	L-band radar
  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
  2.205         NASA downlink
  2.206         SPOT recon platform
  2.211         TDRS
  2.2175        NASA downlink
  2.250         NASA downlink
  2.2875        NASA primary digital downlink
  2.280 - 2.304	Early warning network
  2.204 - 2.400	Deep space probes
  2.300 - 2.550	S-band radar
  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
  2.390 - 2.450	Amateur radio
  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
  2.700 - 3.700	S-band radar
  2.840         H20 resonance
SHF----------------------------------------------------------------------------
  3.300 - 3.500	Amateur radio
  3.700 - 4.195	C-band satellite TV, channels 1-24 on (3720 + 20*(chan-1)) MHz
  4.200 - 4.300	Radar altimeters
  4.950 - 5.000	Protected radio astronomy band
  5.031 - 5.091	MLS (microwave landing system)
  5.150 - 5.350	802.11a wireless LAN
  5.255 - 5.925	C-band radar (aviation WX radar at 5.4 GHz)
  5.650 - 5.925	Amateur radio
  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)
 13.40 - 14.40	Ku-band radar
 15.35 - 15.40	Protected radio astronomy band
 15.70 - 17.70	Ku-band radar
 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
 23.00 - 24.25	K-band radar (police radar on 24.150 GHz)
 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.

Satellite Navigation

System Signal Freq. MHz BW MHz
GPS L1 1575.42 15.345
L2 1227.6 11
L5 1176.45 12.45
QZSS L1 1575.42 12
L2C 1227.6 11
L5 1176.45 24
E6/LEX 1278.75 20
GLONASS I L1 1602  6.5
L2 1246  5
GLONASS II L1 1575.42  6.5
L1 1600.995 15.365
L2 1248.06  8.75
L3 1202.025 20.46
L5 1176.45 10.22
Galileo E1 1575.42 12
E5a 1176.45 12.5
E5b 1207.14 12.5
E6 1278.75 20
COMPASS CPII / Beidou E2 1561.098 16
E5 1207.14 16
E6 1268.52 16
B1 1561.098 4.092
COMPASS CPIII / Beidou B1-2 1589.74 4.092
B2 1207.14 24
B3 1268.52 24
B1-BOC 1575.42 16.368
B2-BOC 1207.14 5.115
B3-BOC 1268.52 35.805
L5 1176.45 24
IRNSS-1 L5 1176.45 4.092
IRNSS-2 S-band 2492.028 16.5

Then there are the microwave band designations:

Frequency Range Microwave / Radar Band Designation
216 – 450 MHz P Band
1 – 2 GHz L Band
216 – 450 MHz P Band
1 – 2 GHz L Band
2 – 4 GHz S Band
4 – 8 GHz C Band
8 – 12 GHz X Band
12 – 18 GHz Ku Band
18 – 26.5 GHz K Band
26.5 – 40 GHz Ka Band
30 – 50 GHz Q Band
40 – 60 GHz U Band
50 – 75 GHz V Band
60 – 90 GHz E Band
75 – 110 GHz W Band
90 – 140 GHz F Band
110 – 170 GHz D Band
110 – 300 GHz mm Band
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