How to transfer digital data to a point 10Km away?

[Manoochehr]

RF Link?

Hello:
I need to transfer some digital data (like data received by a typical GPS module) to some point say 10Km far from it. Do anybody have useful info or advice? I guess that using digital modulation is recommended, but which one? PSK, FSK, QPSK, or ?
I need it for MS project. Thanks! 8)

 

[ali]

RF Link?

Hi Manoooooch,
If you only want use ready madules the best choice for you is using QPSK it is the best power efficent and if you want to design a moudle the best choise is ASK and afther that FSK and then PSK
because they are very easy to design and implementation.
Best.

 

[Manoochehr]

Re: RF Link?

Thanks for your advice about the modulation, but I need some practical circuits or ICs to implement mensioned systems ( RF link for about 10Km)!

 

[yakult]

Re: RF Link?

It depends on the bandwidth and bit rate. For simplicity, you can use ASK or FSK because it is easy to be implemented in hardware. However, if you need bandwidth efficiency (less bandwidth high bit rate). I suggest you to use phase modulation like 8PSK.

For long range communication. I suggest you to use FSK since it's hardware implementation is easlier then other phase modulation. The modulator and demodualtor is easily be implemented.


Yakult

 

[flyhigh]

Re: RF Link?

Hi,

well, RF link can mean a lot of things. You have to specify the frequency of operation. It is determined with regulations and international standards. For 10km range you can work on arround 2.5 GHz, 13GHz, 18 GHz, 24, GHz etc. There might be some more bands, I am not quite sure. The construction and thus the circuits you will be required to use are determined by the choice of the working frequencies. One of the choices you have to make is also the type of antenna, etc. These are tipically duplex links (you din't specify do you need it as duplex), so a duplexer is needed to separete Tx from Rx ...

It is quite of a story!

flyhigh

 

[scoppulal]

Re: RF Link?

hi,
the answer could be 802.11 with modified AP and directive antennas (if you need a high transfer rate)... if it is legal in your country to make such a long distance links.

Otherwise, it depends, also, on the bandwidth, for example if you need few kHz you can use a "normal" FM radio in the VHF/UHF bands (speed up to 9k6), it could be a good choice.

You have also to think to the radio propagation... the two locations are in sight? Are there any obstacols? things like that (Fresnel zone clearance)

There are many solutions.

Ciao

 

[pva]

RF Link?

Hi,
my opinion is that FSK has many advantage for VHF/UHF bands.If you want to transfer only data from GPS you don't need high bit rate.