Using 1/4 dipole antenna on RF module

433mhzantennaRF

Good day to you all. Am new to RF designs. Presently, am working on a device using RF module for transmitting my signal from TX to RX. Am using the common 315-433MHZ RF module bought from ebay.

My questions are:

  1. Can I use 1/4 whip antenna for this considering a distance of 60m?
  2. Can I place the antenna indoor (for both tx and rx), what is the
    maximum distance it can go if placed indoor?
  3. If I can't place the antennas indoors, what is the best cable to use
    to extend the antenna outdoor?
  4. the SMA connector of the antenna has the inner pin(antenna) and the
    screw(body). Do I need to ground this body to my circuit ground?

I have executed this project before using normal portable radio receiver antenna but I had so much interference issue.

Best Answer

  1. That depends on the transmission power and receiver sensitivity. The 433 MHz band has fairly generous power limits for non-continuous (< 0.1%) transmissions.
  2. That should work in general, but will of course attenuate the signal, so you need some power reserve for that.
  3. The best cable is coax, impedance matched to your transceiver circuit. Most use 50 Ohms.
  4. The shielding should be connected to something with a large capacitance. Ground is usually the best choice.

The shielding isn't terribly important for the antenna itself (it wouldn't work if it were shielded), but if you don't connect it, the RF characteristics will be slightly off.

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