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I've often heard people saying that 4G uses the 1800 MHz band but precisely what all frequencies does it work upon? Does it mean that is just uses one frequency i.e. 1800 MHz, well in that case wouldn't there be interference among signals carrying different data.

  1. What is the difference between a frequency band and frequency channel?
  2. Why don't we directly use frequency ranges to tell what a particular technology operates upon instead of telling what band it uses. For example, why do we say that 4G uses 1800 MHz band instead of saying it uses frequencies between X MHz and Y MHz. Wouldn't it be easier to understand?
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A frequency band represents a range of frequencies, which are usually defined by law or regulation. For instance, the 1800 MHz GSM band ranges from 1710.2 MHz to 1879.8 MHz, according to Wikipedia. Bands are wide enough to contain many signals without interference (universally, as far as I know). Because the frequency bands for a particular service are generally widely-spaced, it's usually quite clear what you mean by the usual shorthand definition of a band, if you're looking at a table showing the frequency ranges for the various bands for a particular service. Yes, it would be more clear to say "the 1710.2 to 1879.8 MHz band", but "the 1800 MHz band" rolls off the tongue much more easily. In amateur radio practice, the shorthand name for a band usually refers to its approximate wavelength in meters rather than the frequency, for historical reasons; for instance, the "20m band" in the US ranges from 14 – 14.350 MHz.

A channel is also a frequency range, which is usually defined by law, regulation, or general practice. However a channel is usually much narrower than a band, because a channel is typically only wide enough for a single signal. The intent of dividing a band into channels is to prevent interference. Sometimes channels are given numbers, but not always. Not all services are channelized; the amateur radio service generally uses unnumbered channels for VHF and UHF FM, according to state-wide (US) or nation-wide band plans, and the 60m band is channelized in the US because it is shared with federal government users, but other bands are usually not channelized. In other words, operators using other ham bands can generally select any frequency inside the band, as long as the entire bandwidth of the signal is within the band allowed by law. (Activity inside a ham band is often segregated by frequency according to voluntary "gentlemen's agreements" to reduce interference.)

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  • $\begingroup$ Thanks alot for the beautiful explanation. Is there a formula that would give me both the upper and lower bound for a frequency band ? Suppose I buy a Frequency band of 50Mhz from the goverment. So now what is the exact frequency range available to me? Is there a formula for this ? Also suppose the range available to me is between 40-60 Mhz so now, do I own the complete 20Mhz frequencies in betwwen 40 and 60 Mhz. $\endgroup$ – Shivam aggarwal Nov 12 '16 at 8:12
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    $\begingroup$ You don't "buy any 50 MHz". You get a license to use spectrum between frequency A and frequency B for purpose C with a maximum power D in a geographic location E for a period of time E. $\endgroup$ – Marcus Müller Nov 12 '16 at 17:14
  • $\begingroup$ In the US you can buy a portion of the RF spectrum that is offered for sale via auction by the Federal Government. Of course, this does not apply to ham radio. Usually, only large communications companies buy portions of the frequency spectrum (e.g. cellular and satellite comms). Have a couple of $Billion in your pocket before you enter the frequency spectrum auction. However, even though you buy (by spending money) it is more like a license than purchasing and owning. $\endgroup$ – K7PEH Nov 12 '16 at 18:48
  • $\begingroup$ @Shivamaggarwal, if you like my answer, please consider accepting it. If you were a large company prepared to spend lots of money at a government frequency auction, you would be looking for so many MHz in a certain band. If you were successful at the auction, the FCC (in the US) would tell you the frequency ranges you got. It might be several non-contiguous ranges; generally all the wireless company cares about is having enough channels or enough bandwidth, and doesn't care if the bandwidth is all in one chunk. There is no magic formula, just decisions by bureaucrats. $\endgroup$ – rclocher3 Nov 12 '16 at 19:46

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