Hi guys

I come across this little transmitter only tag, I am just curious how it may work. I am guessing the pic (12f629) send out some kind of on/off keying to the oscillator, and the receiver decode those info.

Another question is how can they make the antenna so short?? it's 433MHz transmitter!!

Thanks guys

 

Hello,

Did you see L2 on the PCB?
That is part of the antenna making it longer.

Bertus

 

Hello,

Did you see L2 on the PCB?
That is part of the antenna making it longer.

Bertus

I thought that might be the case, what do I need to google to read more about this? eg how to decide what inductor to use to make a Xmhz 1/4 wave antenna into Ymm??

 

I thought that might be the case, what do I need to google to read more about this?

Bottom loaded antenna
Bottom loaded vertical antenna
Base loaded antenna