[SOLVED] 433mhz RX TX module problem

Regards,

I have problem, after I make RX TX 433MHz module circuit, when I try to test it I had some difficulty.



I make all, connect to the same power source of 12V PC Power supply unit.
RX need 9V, I put 7809 with 100uF to make appropriate voltage needs of RX module.
TX need 12V, and I direct connect power to ATX power supply.
Both are on the same power source now!
I connecting and disconnecting (clicking) +5V or +12V of power supply on data in of TX module, led light blinks, and I tune RX unit, when I finished adjusting led light of TX and led light on RX blinking in the same rithm of clicking on TX data input side.

After that, I try to separate modules, and try to use different - separate power sources, but no success!

Only works when on the same source of power why ?


This is translation of text from circuit picture:
Superregenerative 433MHz receiver for remote operation and data transfer.
This transmitter and receiver was originally designed as a wireless remote control for example the codec IC HT600 as alarm or car door lock operation but is also suitable for wireless connection between two computers, via the COM port used to about 100 meters.

Both transmitter and receiver can operate from the same or separate power supplies. When you separate both units, as their RF circuits are farther from each other, they must be tuned to the same frequency and possibly use a short (quarter-wave) antenna each, to properly transmit at 434 MHz.
For adjustments I would suggest to use an audio amplifier connected to the output of the R-C filter before TL072 opamp, or, to the output of the first stage of TL072. Use a TTL audio frequency, e.g. 1 kHz, to modulate the transmitting oscillator. As you can hear the transmitted tone, gradually separate the receiver from the transmitter and tune the RF circuit for best results.
I used a similar combination many years ago, and with the quarter-wave antennas the range was ~50 meters, also through a home with concrete walls.
Be patient and expect the TTL output from the receiver to be good only after the proper tuning of all circuits.

Ok, thanks,

I will try to tune again.

I make PCB with antena on it. Both RX and TX have the same shape and dimesnion of antenna 2,2cm long and 1,2cm wide, track is wide 2mm, shape of antenna is П just like on circuit diagram.





Hey man you are right, I do fine tuning and works!!!! :smile::smile::smile::smile::-D:-D:-D:-D:-D:-D:-D:-D:-D


Thanks, thanks, thanks, .....


I will play now to improve range, fine tuning to increase range.

thanks again

What is the value of inductance coil you have used??

alisufian said:

What is the value of inductance coil you have used??

Click to expand...

I do not remember the inductance value; I used an u-loop made of a 1.4 mm copper wire, approx. 15 x 15 mm square, tuned by a 3-10 pF trimmer, plus the e-c transistor capacitance, then an AF139, a popular UHF transistor.

For an extended range use a corner reflector or a dish with your dipole in focus, or make a Yagi. Good ideas can be found in ARRL Radio Amateurs Handbook, any edition.
If you transmit a tone signal like 1 kHz or so, use a selective amplifier ( tuned filter) in receiver for the best results.