I have a question and will be very happy if anybody can help. Thanks for that!
I have a remote control which works with 315MHZ but I can not use this frequency in long range and I want to change the frequency to 433MHZ.
I can get easily remote control with 433MHZ, but the receiver is very difficult to change and it would be very costly.
Now my toughs, I buy a 433MHZ remote control and let it program with the same information then the original. But now , we would have the problem with the receiver, my idea, would be that i use a module which receives the 433MHZ signal and send it out in very short range with 315MHZ to the receiver. (As mentioned, in long range i can not use but in short range). But now my questions, is this possible that you can change the frequency or would be there a problem with the data which you send.
I know it sound a bit wired but I can not use 315mhz in wide range.
does someone know a device which could do this? or must be custom made?
Thank you very much for your answers, I really appreciate!! Have a great Day! Rogasi
All other things being equal, increasing the frequency will actually decrease the range, due to propagation and antenna length considerations.
To increase range, the most effective change you can make to a given radio is to improve the antenna. A typical RF remote has a very short antenna, which you could replace with a straight wire cut to 1/4 wavelength (24 cm for 315 MHz), on both the receiver and transmitter. Better yet, use a 1/2 wave dipole, with one interior connection to the antenna terminal, the other to ground (overall length 48 cm for 315 MHz).
The example in the photo below is for 433 MHz. This setup, with dirt cheap radios, works well at 500 m separation, with clear line of sight between TX and RX.
You didn’t provide any specifics about what type of data (toggle switch states? joystick positions? walkie talkies? Serial data?), which modem pair are currently in use, distance values describing what long and short range means to you, installation-specific details like terrain, obstacles, local interference concerns.
However, there’s nothing substantively different between the 315 and 433 radio bands. There also seems to be a question about modifying the radios? You won’t be able to change a 315 device to 433.
Its for car, my remote works with 315mhz but need to chnage to 433 or 868mhz.
I get a key easily for 433 or 868mhz with all datas on it like the 315mhz.
But if i use a 433mhz or 868mhz then i need to chnage the ECU, but this i dont want, therefore, I want to have a device to step done my signal from 433 or 868 to 315mhz, “basically” a signal repeater ((((Input 433 MHZ or 868mhz and output 315mhz ))))
Wow this is really convoluted. Your car and its KFOB are at 315MHz, and you want to change the KFOB to 433 or 868 while keeping the car at 315. That requires some sort of transceiver that downconverts 433 into 315. And because your car is receiving the information wirelessly you want to such same device to downconvert from 433 to 315 and then re-transmit at 315. The concept is acttually not too complex, a simple mixer circuitry would do the down–conversion you require. But you need to know what bandwidth the KFOB uses, select either high-side or lo-side LO, have some sort of pre-amp (for the 433M side) and post-amp (for the 315MHz side), and two antennas (one for RX at 433, and one for TX at 315). And this all assumes I understood your convoluted need of one-way only as correct. Technically is certainly possible but seems like overkill - why not either get a new KFOB or a new ECU.
To be fair, you could try to hack this by using a cheap one of these; https://www.sparkfun.com/products/10532. Condition the output and connect it to one of these; https://www.sparkfun.com/products/10535. Assuming the KEYFOB uses simple OOK. But if something like this works, the reliability would be very questionable.
