I need a solution for a continual 25km wireless

[verilog_crack]

25km wireless

Hi,
I need a solution for a continual wireless.
It must work for 25km radius.
My problem is the mobility of data transmitter.
The required bandwidth is about 5kbit/s.
I have one central station with 100 mobile stations.
best regards

 

[biff44]

Re: 25km wireless

coding gain is your friend.

 

[jasnoch]

Re: 25km wireless

From your post I'm not sure if you want to design equipment to do this long range wireless thing or you want to buy existing equipment. If the later then take a look at Maxstream at http://www.maxstream.net . They have been around a while and though I have not personally used them I know of people who have and they have no compliants. But read the next paragragh regarding enviroment since it applies to bought equipment too.
If you want to design equipment for this application then two fundamental things to consider. Firstly the regulations governing maximum allowed transmit power for the country in which the system will be used. In the US for the ISM bands it is 1W with up to 6db of antenna gain. (see part15 regulations for exact wording since the last statement is a "kinda sort of" statement). Secondly the enviroment in which it will be used. For example out in the middle of a desert with line of site and directional antennas you may get the range you are looking for and still be within the legal power limits but if the same system is used indoors in an urban situation this will greatly decrease the distance that the system can be used over. To the point that you may only get a thousand yards or so.
It's hard to know what else to tell you without some more details but hopefully there is some food for thoguht here.

 

[verilog_crack]

Re: 25km wireless

Hi,
Yes it's in the city with high height buildings.
If I want to buy an existing equipment can you tell me more.
and I think I can use more transim power.
thanks for your foods
best regards

 

[jasnoch]

Re: 25km wireless

Hi,

I am thinking that you are looking at a paging system here. Is that right? What are you wanting to send over the wireless sytem? How will it be used? If it is paging then you have some advantages over using the ISM bands since paging uses lower frequecies for the RF channel and you can use much higher power. In most countries you will need a license to operate the system legally though.