hybridmetta
New Member
Hi everyone. Im trying to build a circuit that will be used for long range communication... and by long.... i mean over the ocean :roll: . Im living in Portugal and this circuit is suposed to have a range of around 6000 km.
I have some ideas on how to do it and i have some ppl helping me but i guess i still need some "superior" help.
Well the brain of this circuit will be a pic16f877 microcontroller. it will have an lcd similar to the ones inside nokia 3310 phones, an ftdi chip for communication with the chip using the usb port of a computer (if possible i would also like to be able to update the firmware of this pic using this same port) and possibly a max1811 chip to recharge a lithium battery.
cuz i need to transmit and receive at the same time maybe i need two diferent oscillators and amplifiers. the oscillators are vco controlled by the pic16f877 using some kind of DAC.
After all this is done, the circuit will obviously have either headphones output or a speaker attached, a microphone, buttons, leds an all that neat stuff.
the obvious problems are... how am i suposed to make a vco stable enough for such a long range communication? how should i place the filter to reduce the noise on the receiving frequency? what kind of antenna should i use? if i have to use 2 antennas... how can i predict the way they will interact? how much power do i need? will a lithium battery do the job? is it better if i use a frequency in hf or some other band? how can i predict the propagation of the waves in this circuit based on the solar flux (considering that i will use hf)? how powerfull should the amplifier be? the vco comes before or after the amplifier? is it legal to use hf to communicate this far without a licence?
i have lots of issues in the structure of this device... and im sure this will take me a long long time to build... still... i wanna try it.
Anyone knows any source where i can look for some info on this subject?
Just in case someone has any doubts on this kind of long range communication... well it was already proved to be possible by marconi in 1901 when he made the first device to communicate over the ocean.
ps: i read on the net that maybe i will have to use a device capable of delivering round 1kw of power? how can i possibly get all that power? it seems to be impossible... at least for a simple electronic hobbies...
Well thanks in advance for any answer that might help me to find a path to build this device.
I have some ideas on how to do it and i have some ppl helping me but i guess i still need some "superior" help.
Well the brain of this circuit will be a pic16f877 microcontroller. it will have an lcd similar to the ones inside nokia 3310 phones, an ftdi chip for communication with the chip using the usb port of a computer (if possible i would also like to be able to update the firmware of this pic using this same port) and possibly a max1811 chip to recharge a lithium battery.
cuz i need to transmit and receive at the same time maybe i need two diferent oscillators and amplifiers. the oscillators are vco controlled by the pic16f877 using some kind of DAC.
After all this is done, the circuit will obviously have either headphones output or a speaker attached, a microphone, buttons, leds an all that neat stuff.
the obvious problems are... how am i suposed to make a vco stable enough for such a long range communication? how should i place the filter to reduce the noise on the receiving frequency? what kind of antenna should i use? if i have to use 2 antennas... how can i predict the way they will interact? how much power do i need? will a lithium battery do the job? is it better if i use a frequency in hf or some other band? how can i predict the propagation of the waves in this circuit based on the solar flux (considering that i will use hf)? how powerfull should the amplifier be? the vco comes before or after the amplifier? is it legal to use hf to communicate this far without a licence?
i have lots of issues in the structure of this device... and im sure this will take me a long long time to build... still... i wanna try it.
Anyone knows any source where i can look for some info on this subject?
Just in case someone has any doubts on this kind of long range communication... well it was already proved to be possible by marconi in 1901 when he made the first device to communicate over the ocean.
ps: i read on the net that maybe i will have to use a device capable of delivering round 1kw of power? how can i possibly get all that power? it seems to be impossible... at least for a simple electronic hobbies...
Well thanks in advance for any answer that might help me to find a path to build this device.