long range wireless transmission

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#1
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hello all.

 

 i am indulged in a project which requires data to be transmitted from clients, within a radius of a sq. km, to a localized server. what would be the most optimum wireless technology for establishing such a task? i suppose x-bee won't work over such a long range.

 

suggestions and advice are always welcome.

 

thank you very much.

Long live my MASTER.

Last Edited: Fri. Oct 16, 2015 - 12:22 AM
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Hello Abbas,

 

for long range communication there are a few ways to increase the covered distance.

 

1. Output power

2. Receiver sensitivity

3. Antenna gain

4. Data rate

5. Frequency

 

First and obvious thing is to increase the output power. Problem is the authority which might complain if your are toasting birds in mid fight. Therefore you have to check what radio regulations are valid for your location. As an HAM radio amature you have some advantages in this matter.

 

Receiver sensitivity is another topic. The more the better. Modern 433 MHz ICs can go as low as -116dB.

 

Antenna gain is an easy way to increase the covered range. Good directed antennas will give you a nice boost but again obey the radio regulations.

 

Data rate can also be used to increase the distance. The lower the data rate the higher the sensitivity of your IC will be. On the other hand allows you a lower frequency tighter RF filters which improves the signal to noise ratio.

 

The last thing you can think about is the used frequency. The higher the frequency the higher the free space dampening will be.

 

My suggestion would be a system in the 433 MHz ISM band. Here you won't get much in trouble with the authorities. Since there is no protection of the allocated frequencies in this band people need to live with disturbers. In Europe you might send with 100mW in the 433 MHz ISM band. ICs are widely available which offer good Rx sensitivity and configuration of the rf protocol. Also 433 MHz is much easier to handle in regard of the antenna design.

 

 

 

 

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Can you use gained antennas? (does the units move), can you make cells from the server (so more than one receiver in server)

Are there problems with size?

 

But in general make server receiver very good, so the rest can be cheap.

 

Which baudrate?

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abbas14 wrote:

hello all.

 

 i am indulged in a project which requires data to be transmitted from clients, within a radius of a sq. km, to a localized server. what would be the most optimum wireless technology for establishing such a task? i suppose x-bee won't work over such a long range.

 

suggestions and advice are always welcome.

 

thank you very much.

 

Abbas,

 

Because of my moderator's privileges, I know where you are, so I can also "guess" that there will be many, many building obstructions in a square kilometer in your city. I would advise against using a dedicated wireless system for this application. I suggest that you investigate using the data facilities of your well equipped mobile telephone networks. I believe that it will be far more reliable/successful in the long run.

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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Multiple devices?  Consider a mesh network.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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Yes it depends on where you are and whats around you?

Are you in a corn field in the USA?

Or a city in Paraguay?

 

can you use mesh networking?

Can you use Cell?

Can you use 900 mhz

Can you use Digis punch radio? It's amazing, but expensive.

 

Details details details

Keith Vasilakes

Firmware engineer

Minnesota

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New Delhi, India.

Ross McKenzie ValuSoft Melbourne Australia

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yes, perfectly right.

New Delhi, India.

 

the objective is the develop a star like configuration, or a mesh like. whichever suites best.

 

data from a locality (may be upto a sq. km. or so in radius) have to be sent to a localized server, which would then bring all that data and info online, updated and freshly maintained.

 

but the challenge is, due to limited size and configuration of the client (slave) devices, they cannot be directly connected to the LAN.

Long live my MASTER.

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Do you want your client to be really stupid, meaning that they can only transmit (so the server will have it's own mesh like placed all over).

or will it work with all clients used as repeaters? (perhaps one client will sit on all traffic to the server, will that work ).

 

So next how many clients max?

And data amount?