Mini 120khz Transmitter !! please Help

[jaydog]

Mini 120khz or 457khz, Transmitter !! please Help

Hi guy' iam trying to make a mini transmitter that can fit in side a tv coax plug it does not need to transmitter far only about 8ft and transmit on 120khz, or 457khz,
any help would be very much appreciated,

 

[cowboybob]

Tire pressure xmitters use 125khz. There are ICs available for that.

 

[audioguru]

Why such a low frequency? The antennas will need to be very long so you might as well connect with wires.

 

[cowboybob]

Welcome jaydog!

Tire pressure monitoring xmitters use a 125khz center frequency. There are ICs (Atmel) available for this task. Might fit in a TV coax connector.

<EDIT>Meant to hit the EDIT button. Sorry for the repeat...

 

[jaydog]

I think it's 457khz, I have the receiver it's a ferret locator. I would like to try to make a transmitter for it .

 

[cowboybob]

Saw your PM.

Look here.

Obviously not small enough as you indicated, just googling around the net.

If you want to build such a device, it would help us to know your current level of electronic experience, since building a reliable and (in your case) very small xmitter 0f this sort could be difficult.

 

[jaydog]

iam new to this so my electronic experience is very low.....but iam willing to try anything !

 

[cowboybob]

Here is a simple, crystal controlled oscillator/transmitter circuit. Simple, but not all that easy to build:



I suggest crystal controlled as that is far simpler to build and have any real hope of signal stability.

 

[jaydog]

Thank you very much for your help,

 

[MikeMl]

Read this thread. Pay particular attention to the comments about antenna length/efficiency.