869 mhz 500 mw transmitter circuit
anyone can help me , to make a circuit for a transmitter
869 mhz 500 mw
I was looking for (possibly simple) schematic , applications, ready to use gerber and any useful tips
I wanted to make a printed circuit board, and draw, where possible, the coils on the PCB.
The work will be shared on the forum
plz tell ur project for which u need this type of circuit(am fm broadcasting signal /or remote keying something)
the circuit should be dedicated to telemetry and automation in agriculture.
The circuit should pass through the SCI of a microcontroller a string of bytes, about 50 / 60 bytes, even with low baud rate, what matters is that it should cover a long distance. ( more than 3 km)
Transmission should be cyclical, every hour or on event
I can imagine many applications, for example, a friend asked me for a burglar alarm for his hives of bees
Maybe is cheaper to buy this:
Radiometrix - Radio Modules - RF Modules - Wireless Modules | TX3H - Press Release
RADIOMETRIX|TX3H-869.50-10|TRANSMITTER, 869.5MHZ, 500MW | Farnell United Kingdom
yeah its always nice to buy these type of comps in these type of projects ,while you are making them as professionaly
a doubt that I came
to cover long distances (outdoor, countryside or mountains)
which frequency is better? (with equal power)
Considering the limitations of the law
433 MHz up to 10 mw (covering 100 m)
869 mhz 500 mw max (covering 5 km)
169 MHz up to 250 mw (covering 10 km!)
If you can do with a narrow beam aerial, I would go for 869 MHz. For the same aerial size, you can twice the erp* of the 433 or five times that of a 169 MHz transmission aerial. * erp = Effective radiated power I would look at the ARRL or RSGB handbooks, these are for radio amateurs who need to get the best range for their transmissions
Frank
And plz never forgot to check the rules of ur country,otherwise they are ready to catch (scientistzzz)
he hee
Consequently, the regulations don't allow higher than dipole gain.