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Will the airwaves ever get full?
Babsefc
Posts: 862 Forum Member
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With all the televison and radio signals, mobile phones, e:mails, wifi, gps etc in use, would there ever come a time when it becomes too busy.
Now I'm useless at technology and my poor little brain can't really comprehend how it all works anyway - but is it a stupid question
Now I'm useless at technology and my poor little brain can't really comprehend how it all works anyway - but is it a stupid question
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http://en.wikipedia.org/wiki/White_spaces_(radio)
We can never use 'all' of the possible frequencies. The higher you go the shorter the distance it will travel for a given power input. That's why car radios need to be retuned more often on VHF than long wave. There must come a point when it becomes impractical to transmit on a frequency.
Lower frequencies go further but can't carry as much information (which is why long wave stations don't sound as good as medium wave and why the time signal for radio controlled clocks takes five minutes to actually transmit the time).
This is why mobile broadband is never going to beat a wired solution. Operators blather on about 4G offering 1Gb/s but neglect to mention that is for an entire catchment area and only applies to the mast itself. It's great at 3am when you're the only person awake and standing beneath the transmitter but at 8pm when everyone else and their dog is trying to use it your slice of the pie can be very small.
More info here.
Edit:Also I didn't know that above 300GHz was blocked by the atmosphere.
It's all very complex but basically - you're right to be concerned. It's a finite resource that needs very careful management.
It's been "too full" for decades, it's only the very strict regulation in the UK that keeps it viable.
Huge chunks are allocated to the MoD that don't get used for example.
Some of us oldies can remember when you could listen to the cops on an FM radio!
Mind you, these days you can listen to cops in other countries over the Internet...
[Not a site recommendation by the way - I've never used it. But I do remember being surprised to find just what was available using the Internet radio feature on my Yamaha AV amplifier. I spent a while listening to various random air traffic controllers!]
The air's probably packed with signals a lot of the time. There's likely more signals going through the air than we think. The following:
Terrestrial TV
Satellite TV
Mobiles
GPSs
Radio
Wi-Fi
That's all I can think of.
too many people want to shout and not enough air to carry all that noise ........
The Cops was on daily, and much better than Mrs Dale's Diary. whats more, listening was forbidden. if you tuned into 100 mhz you were being very very naughty.
In the simplest terms, I can use the "internet radio" app' on my phone to receive "transmissions" from a multitude of different radio stations all via one wifi broadcast.
I suppose it'd be possible, for example, to build smart radios capable of decoding the data and then broadcasting one honking great muliplexed digital radio signal.
I sometimes wonder if we're all going to end up mutating due to the amount of energy being zapped into our bodies by broadcast transmissions.
BIB Funnily enough a friend of mine just said something similar
Yep guilty as charged too!
We used to huddle round the wireless daring not to make a sound in case they could hear us:o
Also what will happen if all the space does get used, will everything just stop working?
The problem with finding chunks of unused spectrum is economy of scale. Its only economical (in terms of equipment cost) to use spectrum for a particular application if there is some kind of worldwide or at least European standardisation. For example Europe has agreed to use the 800MHz spectrum freed up by digital switchover for 4G, there is also freed up spectrum at 600MHz but the UK couldn't go it alone there as nobody would make mobile handsets just for us. There are exceptions, for example our PMR bands are so congested we use parts of Band III (the broadcast band DAB uses) for PMR in the UK. Also part of an MoD band was given up for public safety use (TETRA), but in general it isn't economical to unilaterally find chunks of free spectrum and start using them. Also, a lot of apparently unused MoD spectrum is actually in use.
We used to huddle round the scanner discussing what we were listening to over the CB (the 80s equivalent of tweeting while watching the X-factor), so if they wanted to they could hear us
White space means using the free space within broadcast bands (usually the TV band) for lower power wifi type signals. A frequency can't be reused for broadcasting in neighbouring areas to avoid interference, but it can be safely used for low power applications. One of the reasons it hasn't been used up to now is that you (or your low power equipment) can't be trusted to know when a frequency is free or not - just because you can't pick up a signal doesn't mean the frequency isn't in use. What has made white space practical now is GPS and online databases that tell you what frequencies are free in your location.
Its an economic thing. Lower frequencies carry further but have lower data capacity, whereas higher frequencies have much more capacity but less range. When you start running out of capacity, the solution is to cover the same area using a larger number of transmitters operating at a higher frequency, which costs more.