IAN LANG ELECTRONICS

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Crib Sheet for the RF Spectrum

Broad Groupings

Name Frequency Propagation Uses Performance Notes
Very Low Frequency (VLF) sub 30 kHz Ground only Navy Operations Time code signals Travels very long distances without significant attenuation
Low Frequency (LF) 30 kHz - 300 kHz Ground, and at night is reflected by ionosphere leading to reflections Long distance broadcasting Can suffer nightime attenuation
Medium Frequency (MF) 300 kHz-3 MHz Ground, and at night is reflected by ionosphere leading to reflections Broadcasting over large areas, a region of a country. MW radio. DRM Lower Band. Can suffer nightime attenuation
High Frequency (HF) 3 MHz-30MHz Bouncing between ground and sky. Intercontinental Comms. DRM Mid Band Is dependent on weather and time of day and year. Needs a range of frequencies for continuous coverage.
Very High Frequency (VHF) 30 MHz- 300 MHz Line of Sight and tropospheric Frequency Modulated broadcasts 88-108MHz Lower part of band for DRM, upper for DAB. Can only be used for fairly short distances.
Ultra High Frequency (UHF) 300 MHz-3 GHz Line of Sight and tropospheric 2&3G Mobile Phones. TV Broadcasts. WI-FI HDTV Satellite television Severely attenuated by terrain features and perhaps the most highly crowded portion after 88-108 MHz
Super High Frequency (SHF) 3 GHz-30GHz Very short and highly focussed distances. Military &Government, Microwave and satellite links. Radar. Used for up and download by satellites, does not travel by ground or atmospheric propogation.
Extremely High Frequency (EHF) 30 GHz -300GHz Very short and highly focussed distances. Military &Government, Microwave and satellite links. Radio Astronomy. After 30 GHz, wavelengths become so short that attenuation is a problem, and are approaching dangerous levels.

Broad Groupings Sub - Division

Sub Division Band f min & max Used For Comments
Band I VHF 47-87.5 MHz European TV, radio control, various amateur frequencies including beacons.
Band II VHF 88-174 MHz 88-108 FM Broadcasts 108-118 Aeronautical Various distress signals, AM Comms
Band III VHF 174-230MHz European TV, DAB 217-230
NATO Band VHF/UHF 225-400MHz Although the top end is now occupied by TETRA Ground Military Uses KEEP STRICTLY OFF!! Unless you want a big black car pulling up...
Band IV / V UHF 470-862MHz UK TV Broadcasting. SDTV, DBV, HDTV PAL UK AM vision carrier lower sideband vestigial FM sound and 25kHz guard band
L UHF 1-2 GHz Many MOD frequencies exist in this band. ALL transmissions are banned at 1.4 GHz 1.8 GHz is DECT Other uses in radioastronomy; SETI is at 1.420
S UHF / SHF 2-4 GHz 3G mobiles, air telemetry, some MOD frequencies C Band satelite 3.7 to 4.2 GHz
C SHF 4-8 GHz Satellite TV in Asia C Band is impervious to rain fade but suffers from ground interference
Ku SHF 12-18GHz European Satellite High Level MOD The topmost band you are likely to come across.

Frequencies and Wavelengths

Band f min f max l min l max Wave
VLF ~ 15 kHz 30 kHZ 20,000 m 10,000 m Long
LF 30 kHz 300 kHz 10,000 m 1,000 m Long
MF 300 kHz 3 MHz 1,000 m 1 m Medium/Short at 1.8 MHz
HF 3 MHz 30 MHz 1 m 100 mm Short
VHF 30 MHz 300 MHz 100 mm 1 mm Ultra-Short
UHF 300 MHz 3 GHz 1 mm 0.1 mm Microwave
SHF 3 GHz 30 GHz 0.1 mm 0.0001 mm Microwave
EHF 30 GHz 300 GHz 0.0001 mm 0.00001 mm Microwave

For VLF the min of approximately 15 kHz is given as radio waves do not propogate much under this. C is given as 300,000,000 m/s but more accurately could be given as 299,792,458 m/s.
Wavelength l = speed of light C divided by frequency f :

l = C / f

UK TV Aerial Groups

Band f min MHz fmax MHz Cap Colour Channel No.
A 471 599 Red 21-37
B 583 727 Yellow 35-53
C/D 687 847 Green 48-68
K 471 687 Grey 21-48
E 583 847 Brown 35-68

In the United Kingdom analogue frequencies are given a channel number more usually than a frequency. If you need the frequency, it's given by the equation:

fvis= 8n + 303.25

Where fvis is the frequency of the visual carrier and n is the channel number. Then you take off the 0.25

For digital the equation is:

fmux= 8n + 306

where fmux is the centre frequency of the multiplex band you're trying to get.