Range Issue of RF 315Mhz Receiver and transmitter using PIC18F4520 microcontroller!

Discussion in 'Wireless & RF Design' started by Shamaas, May 28, 2013.

  1. Shamaas

    Thread Starter New Member

    May 17, 2013
    Hey Everyone!
    I just used an RF transmitter and Receiver of 315Mhz to send and receive data through PIC18 Controller! The language I used to program it was mikroC.
    First, I used a mono-pole straight antenna with it and used the transmitter to send data to receiver! The transmission and reception was working for quite a good range. Next, I thought of attaching both the receiver and transmitter to my two microcontroller modules. I did this so that when my Master(Transmitter) would transmit some data, then my Slave(receiver) could acknowledge him back too that the data had been received successfully. After I programmed it that way it was still working fine. The problem came when I tested it's range which had reduced considerably. The range went to almost more than half as it was when I was using just a single transmitter and receiver.

    My question is does anyone know what might be the problem as to why my range of data communication has reduced so much? And can anyone please also do give me some tips as to how can I resolve this issue?

    I have attached a picture of transmitter and receiver I am using! I would be very thankful If I could get some pointers on how to solve this issue!
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    So, each microcontroller has one of each: receiver and transmitter?

    If so, then your transmitter might be making the gain in the local receiver decrease since the signal source is so close (and strong). If so, you could try transmitting the data several times, while the other transmitter is off, of course (this is half-duplex, afterall) in order to get the other receiver to get to the correct gain.

    Roman Black just posted a rather interesting look at those little modules, you may want to take a look, here.
  3. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    Thanks for mentioning my page Tshuck. :)

    To Shamaas, re the drop in range after using both TX and RX at each end, how have you arranged the antennas?

    Are you running 4 stick antennas now? Or have you connected the TX and RX modules both to the same stick antenna? Photos would help!
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    Good information begs to be shared! :)