2
\$\begingroup\$

I have constructed a half-wave dipole antenna for the 433MHz frequency.

I'm using the antenna to receive in a simple setup, where I measure the output power of a transmitter.

Everywhere I read about the antenna is stated that the impedance is about 75 ohms, so if the antenna was used to transmit, I can be seen as a 75 ohms load, and therefore is simple to match. Ok, I got this...

But I cannot find how to match the antenna, when using it as a receiver?

Is it just a source with 75 ohms output impedance, or is a dipole not good for receiving?

\$\endgroup\$

1 Answer 1

Reset to default
6
\$\begingroup\$

Dipoles are excellent for receiving. It would appear as a 75 ohm source, as you guessed. Impedance matching is usually more important for transmitters because of the levels of power involved. Mismatched impedance with receivers doesn't tend to melt anything, because there are only micro-watts of power involved, but you may get more signal into your receiver's front end if you match the antenna.

\$\endgroup\$
2
  • \$\begingroup\$ Okay, Thanks! :-) But if add a larger load impedance on the antenna, say 1K ohms, would I get a larger voltage? (I'm adding a amplifier, so a larger voltage would be nice). \$\endgroup\$
    – JakobJ
    Apr 14, 2011 at 7:05
  • \$\begingroup\$ yes you'd get a larger voltage, but you'd achieve less actual power transfer. Not that it's all about power transfer with receiving, but it does help. \$\endgroup\$
    – JustJeff
    Apr 14, 2011 at 11:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.