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Personal/group cell-phone relay

For places that are within a few hundred feet of good cell reception
  [vote for,

In many places such as factories, cell phones can be nearly useless even though good reception can be had outside. My proposal would be a box which a person could have outside such a business or in an area which gets good reception (or, depending upon range and where he's parked, in his car), which would then have a wireless link to a handheld phone set.

Depending upon the placement of the unit and the frequencies used, it may be able to greatly enhance the cell phone performance for people like contractors working inside a factory or other metalic building. Although such a unit would probably cost over $300, it could easily pay for itself if it prevented many wasted minutes' worth of either dropped calls, "Can you hear me? How about now?", and time spent trying to move to an area of decent reception. At $60/hour, every minute saved is a dollar saved. While the device wouldn't pay for itself overnight, it wouldn't take terribly long either.

supercat, Sep 18 2002

Cellular Repeater http://www.wtw.to/tu-e.htm
Pretty much as described with the added bonus of a hilarious translation to English. [bristolz, Sep 18 2002, last modified Oct 04 2004]

Building Repeater Packages http://cellantenna....ilding_repeater.htm
"Solve dropped call problems inside buildings including shopping malls, parking garages, office buildings, restaurants, hospitals, steel hull ships... "
Look, they're having a sale on their cell phone 3W "booster." $289/USD [bristolz, Sep 18 2002, last modified Oct 04 2004]

The solution ;-) http://www.antennabooster.net/
"...works like a dish on a satellite to capture and emit a stronger signal." [half, Sep 18 2002, last modified Oct 04 2004]

Not the solution http://www.rkdm.com/donkey/index.html
[half, Sep 18 2002, last modified Oct 04 2004]

Spotwave http://www.spotwave.com/
Another company has subsequently baked this. [krelnik, Jul 31 2005]

zBoost YX510 http://www.repeater...oost-dual-band.html
This one too. [Camslozano08, Aug 06 2009]


       I have a friend who was at one time working on a project for a telecom company. They were developing a mini-cell for the home which would connect via the phone line in the home and allow calls from your cell handset to be made across the standard phone line and in progress calls would somehow be passed to or from this mini-cell as you approach or depart your home. Such a device would likely be able to do the job described in this idea.   

       Sorry, no links or additional details available.
half, Sep 18 2002

       As long as places that are shielded to keep out bastard EMF emitting devices can't be buggered by an x10 relay (disguised as an umbrella - for example) left by the entry, I'm all for this.
reensure, Sep 18 2002

       These do sound like the right concept, though I don't know (1) where the products in the first link are available/legal to use, and (2) what frequencies they use. Since they don't specify otherwise, I would guess that they use the normal cell phone frequencies, which would suggest that they'd have the same reception problems as a normal cell phone. My thinking was that since different frequencies penetrate things differently, converting to a different frequency might improve things (even though it would then require use of a different phone).   

       As for the products in the second link, those too sound like a nice concept, though they sound more like they'd be designed for "permanent" installation. My concept was something that a contractor could easily have with him at a job site to be able to troubleshoot equipment, etc. Unless it could be easily installed and removed, a "permanent" base station device seems a bit inelegant for this type of use.
supercat, Sep 18 2002

       You just need one of these boosters (link). It must work, they advertise it on TV.   

       Then again, the same site sells something called a "Smoking Donkey" ('nother link) and a "Jesus Bobblehead" so the credibility of the booster may be even more suspect than I had imagined.
half, Sep 18 2002

       The "cell phone" booster things are about as useful as the "cell phone radiation protectors" that stick on the earpiece. Interestingly, I saw both sold together in the same package at a local store.   

       One difference, I think, between my solution and the others is that the others seek to relay cell phone signals "as a group", whereas my concept was that the remote unit would appear to the wireless provider as just an ordinary cell phone and then a tranceiver for talking to the handset separately from the cell network.   

       It would be roughly equivalent to taking a cell-phone-to-landline convertor and then plugging a cordless phone into it.
supercat, Sep 19 2002

       I think that this might be a problem with one of the American mobile phone formats. This is not a commonly reported problem with GSM.
Aristotle, Sep 19 2002

       [supercat]: I didn't quite grasp all of that from your initial description but I was thinking along the same lines. (My suggestion for using the "booster" was intended to be humourous. Probably should have saved the donkey link for a smoking idea.) The cordless phone would also probably have some of the same RF communication issues as the cellular, depending on the reason for the problems with cell communication in the first place.   

       I'm not a cell phone junkie so I don't know for sure, but I would guess that the cell phones that act as modems would allow control of their dialing, call termination, etc. from the interface port. Seems like a traversable step from there to where you want to be. Does the interface port on a cell phone also provide access to the incoming/outgoing voice signal?   

       Bakability (bakeability?) seems pretty high. Maybe with off-the-shelf technology. Bury an old PalmPilot in there for the processor, RS-232 interface to the cell phone, and user interface.
half, Sep 19 2002

       The cell-phone to interior-handset link would be subject to many of the same vagarities as any other RF signal, but cordless-phone spectrum is available at 47MHz, 900MHz, and 2.4GHZ, frequency bands. Since different frequencies are affected differently by building structures, one of these bands might work when others fail.
supercat, Sep 19 2002

       //47MHz, 900MHz, and 2.4GHZ// Does anyone manufacture a frequency switching/switchable phone?   

       Smells like a real live prototype's a brewin'. Go forth and bake.
half, Sep 19 2002

       All this shall be baked in due time. 3G and 4G are on their merry way to the world. Its starting already with GPRS in Europe. Picture messaging...video messaging....ubiquitous access...'Personal Distributed Environment'.   

       Sounds like a dissertation I once wrote on the subject....Website & Links pending...
Jinbish, Sep 19 2002

       I can't find any decent papers/links so here goes...   

       One of the concepts of 3G and 4G mobile telecommunicatipns is to have a multi-technological hierarchy with potentially reconfigurable terminals to provide ubiquitous access and greater roaming capability.   

       What this effectively means is that you can be using your mobile phone/PDA/thingymajig through some kind of wireless LAN (local area network with high capacity to ensure good coverage) while you are in the office.... when you leave the office the phone 'crosses over' to the cellular network...when you get to your car it uses something like bluetooth to connect to a bigger transmitter in the car which in turn connects to another LAN arrangement. The device is always provided with the best access possible.   

       The idea is good...and I'm not criticising it, and its not baked... but the 'repeater' concept is being investigated, along with connecting people to the most appropriate network.
Jinbish, Sep 19 2002

       I know people are working on all sorts of new technology infrastructures. What I'm proposing is a device which will work with the existing infrastructure and can easily be set up or taken down as needed (e.g. less than five minutes to set it up somewhere the first time, less than one minute to set it up again on later visits, and less than a minute to take it down).   

       The goal here is not to require new technologies, but merely to make existing ones work better.
supercat, Sep 19 2002

       Ok, thats fair enough. I'm with you. But now I have my thinking cap on, it may get a little messy...Erecting a short term radio transmitter in such an ad-hoc manner has to be considered carefully. Many issues will have to be addressed: (eg.)   

       1) Interference
2) Multipath Propagation
3) Synchronisation
4) Location and Network Management

       I guess the most natural solution would be to have some kind wireless LAN throughout the factory...but that defeats the whole 'one box' idea. To try and use this idea, the radio environment really has to be scrutinised. Its not just a case of receiving and re-transmitting on a better frequency. Is one small portable base station going to be powerful enough to solve the problem? If it is, it'll have to be designed so that it works in a worst possible scenario to be of any use. Would workers want it placed inside their factory?   

       The closest solution I can think of that would fit your concept idea would be a kind of hybrid phone/walkie talkie technology. Which is emanently bakeable (although I know nothing of w/t radio technology).   

       While I have my thinking cap on, I'll think you up a croissant for the idea anyway.
Jinbish, Sep 19 2002

       It's called a repeater and if your coverage is bad you can ask the mobile operators in you area to install one.
krutius_orb, Sep 20 2002

       //Is one small portable base station going to be powerful enough to solve the problem?//   

       Well, at many of the job sites I've been at, most of my work has been within a hundred yards or so of a spot where I could get cell coverage, so a single well-placed relay could be adequate.
supercat, Nov 30 2004

       I think this is a great idea. This would work well while you're in your car also. An antenna on the outside of your car connected to your car's battery should get a much better signal than your cell phone.
Worldgineer, Nov 30 2004


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