RF circuit diagram

[wowowee]

hey guys, does anyone have a circuit diagram for testing RF rx/tx? somewhat like to test if an RF signal is really being transmitted and received.

 

[Papabravo]

hey guys, does anyone have a circuit diagram for testing RF rx/tx? somewhat like to test if an RF signal is really being transmitted and received.

You might be talking about a spectrum analyzer. That will certainly tell you if RF is being generated by a transmitter.

 

[wowowee]

You might be talking about a spectrum analyzer. That will certainly tell you if RF is being generated by a transmitter.

i actually mean a circuit diagram to test an RF module. do you have any?

 

[Nigel Goodwin]

You need to be FAR more specific!.

 

[Papabravo]

i actually mean a circuit diagram to test an RF module. do you have any?

No a spectrum analyzer is a complex instrument. It's not something you can throw together from a schematic.

 

[evandude]

If you just want an indication of whether the transmitter is broadcasting power or not (just to check for dead or very weak units), you can use a field strength meter. You can buy them as handheld instruments, I think you can get cheap ones for $25-40, or if you want a very basic solution you can build one with an antenna/coil and some discrete components, with a multimeter to read the output, do a google search and you should find something. I've used this kind of circuit to tune the transmitter of a cheap R/C toy (tweaking a variable inductor inside - clearly it came detuned because the range more than doubled afterward) - it consisted of little more than a coil of wire, a diode or two, and a few capacitors, and took just a couple minutes to put together. Exactly how you do it is going to depend on what frequency your TX operates at.

And as everyone always says, PLEASE try to actually include relevant information when asking a question. You don't give any information so nobody knows for sure if you're trying to perform a detailed spectral analysis or just see if a TX is dead, or what type of transmitter you're talking about, or what frequency it operates at.

 

[Nigel Goodwin]

At a guess, I would assume he's talking about licence free radio modules?, but as he's never given us a clue it's impossible to answer him with any degree of confidence!.