3 km communication

hello

i need communication with only text with my other arduino 4 km further away. the transeiver has to be under $7. know any a good one?

thanks

know any a good one?

There are not even any mediocre ones that can transmit 4 km for under $7.

I am assuming you want an RF transceiver and not a wire transceiver, correct?

If RF, then have you done any sort of radio path analysis, buildings, tress, hills or other structures will effect RF at various frequencies in some way?

Will you need licensing to operate an RF transmitter of some ERP in your area of the globe?

Why is it so important that it 'has' to be under $7 of which currency? You know you will need two, so that increases the cost budget quite a lot for you I would say.

You don't mention what speed you require, 110 baud or 115200 baud, maybe as low as 50 baud? You don't mention if you need bi-directional data path or if you only need one way communications?

I guess for a few bucks you could make a spark gap transmitter :o Ah, so few details :sleeping:

i mean 1 transeiver module for $7 and total for 2 $14. but for 1 module is $13 good too. as long as it dont cost my for example $50 to sent 15 messages of 20 letters long per hour. becouse i want to sent only 15 messages of 20 letters long per hour. i live in the netherlands. is that long range allowed? it doesnt matter my what frequention if it is higher than 108 mhz.