send digital data in 4 Kilometers

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baby_1

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Hello
i have a digital string that want to transfer in 4Km distance.i can't use wireless communication and should use wire to transfer.how can i send data with 500Kbit/second and without any repeater?
 

Almost imposible.
U will need to modulate it like internet used thru phone lines...pcm
or use fiber optics.
 
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Dear baby_1
Hi
What wire ? can you use power line wire ? if yes , i offer you an old way , for this aim , it based on dispatching systems via power line . but for better guidance , more information needed .
Best Wishes
Goldsmith
 

baby_1 said:
Hello
i have a digital string that want to transfer in 4Km distance.i can't use wireless communication and should use wire to transfer.how can i send data with 500Kbit/second and without any repeater?
Click to expand...

Use WiFi directed antennas, TCP/IP.

Just one standalone example, you can make anything:
 

Lets assume he does not have pwr line and dont want to use wifi or tcp/ip and dont want to use a simple cheap repeater... so what then ? and he did not answer my option about using tone burst say 1k for '0' logic 5k for '1' logic which later can be converted to logic level pulse .
**broken link removed**
 

A DSL type of signal modem may allow you to go 4 Km over a telephone twisted wire pair.
 
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He can always use directional antennas for zigbee or other modules.

**broken link removed**

**broken link removed**

But I think elegant solution is WiFi.


Also if there is GSM coverage he can use GPRS or 3G or even SMS for transfer data.
 

Hello and Thanks
as dselec said i want to use QAM or QPSK modulation to transfer my data.could you introduce me some IC , circuit or reference that show me the theory and designing consideration about QAM and QPSK?
 

I am talking about something much much simple than all-that.
simply switch a sine wave on and of with your pulse on and off with 500kbit
**broken link removed**
any way if u insist using the other ill find a circuit.
first start using spice to make the oscillator.
or dismantle a cheap home telephone with tone dialing ...
the idea is to use-number 1 and num 3 as 2 tone and sent it thru phone and at other side connected it to tone detector.
http://www.google.co.il/search?q=to...WJ8iR8gOHnfCwDA&ved=0CFMQsAQ&biw=1280&bih=823
http://www.google.co.il/#hl=iw&q=dt....,cf.osb&fp=6d3008f70f3f3c5d&biw=1280&bih=823
 
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A phone DTMF tone is much too low a frequency to sent 500kbit/s data. The tone frequency would need to be sufficiently higher than 500kHz to give at least several cycles of the signal to detect the presence or absence of the tone.
 

Right i just set up ltspice with 1 Mhz carrier and it work fine .there is some more work on the filters and i am trying am and fm as well to see what is the best way.
next i will try freq shift and pass it into a long telephone cable i have and see how fast the decoder works , this project is interesting and i am taking personal interest in it..
 

baby_1 said:
Hello
i have a digital string that want to transfer in 4Km distance.i can't use wireless communication and should use wire to transfer.how can i send data with 500Kbit/second and without any repeater?
Click to expand...

What wires do you have now, what type, between this two points ?

Is there is some special reason why you whant use wireless communications ?
 

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