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How does a Mobile Phone Work? |
k700nut
Joined: Sep 29, 2004
Posts: > 500
From: manchester,england.
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I could explain how transmitters and receivers work,but it would take many posts.yeah radio hams use 144-146mhz(2m band),and i think 430 to 434mhz(uhf 70cm band).many people are under the impression that a large antenna works better,whether it be for receiving or txing,but it's quite simply not the case.like i said a cb transceiver works on 27mhz(hf) and uses a huge vertical 18ft(or horizontal)antenna.if you was to use this antenna on a phone,the mismatch would be huge,and the phone would barely function!
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kinc
Joined: May 15, 2004
Posts: 226
From: Bh,England
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It's all done with invisible lengths of string. 
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k700nut
Joined: Sep 29, 2004
Posts: > 500
From: manchester,england.
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Here are some basic radio facts;radio waves(rf)travels at 300,000,000 m/s.a simple way of working out antenna length is like this;i'll use a phone on 900meg as an example(o2,voda)300000000(speed of rf)\\900000000=0.333,which means gsm 900 would be on the 30cm band.antennas are often half wave,or quarter wave.so the full aerial length would be approx 7cm(remember the coils inside old stub antenna)in full length when uncoiled.
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Access the forum with a mobile phone via esato.mobi
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Posted: 2004-10-07 19:41
