Simple RF transmitter frequency changes

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bibob45
Newbie Pyro
Posts: 2
Joined: Wed Oct 09, 2013 12:16 am

Simple RF transmitter frequency changes

Hi,

I'm working on a RF transmitter for a robotic project and the Simple Pyro RF transmitter project helped me a lot with my understanding of how a RF transmitter works.

However I was wondering if there is any way to scale down the emitting frequency of the oscillator. I'm working with a 10Mhz crystal and i would like to know if there are any formulas to scale the surrounding capacitors, resistors and inductors of the oscillator to change it's emitting frequency to 10Mhz instead of 27Mhz.

Thanks a lot,

Thomas

ThePyroElectro
Posts: 1181
Joined: Mon Nov 12, 2007 9:24 pm
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Re: Simple RF transmitter frequency changes

bibob45 wrote:Hi,

I'm working on a RF transmitter for a robotic project and the Simple Pyro RF transmitter project helped me a lot with my understanding of how a RF transmitter works.

However I was wondering if there is any way to scale down the emitting frequency of the oscillator. I'm working with a 10Mhz crystal and i would like to know if there are any formulas to scale the surrounding capacitors, resistors and inductors of the oscillator to change it's emitting frequency to 10Mhz instead of 27Mhz.

Thanks a lot,

Thomas

Hi,

For the transmitter you just swap out the 27 for your 10 MHz.

For the receiver you need to adjust the Inductor/Capacitor tuning (tank) circuit so that it is centered around 10 MHz instead of 27. Typically this means modifying the inductor in the tank circuit.

http://www.daycounter.com/Calculators/LC-Resonance-Calculator.phtml

An LC resonance calculator might be handy for you. Although that equation isn't exactly complicated, so perhaps the online calculator is redundant.

Good luck!

bibob45
Newbie Pyro
Posts: 2
Joined: Wed Oct 09, 2013 12:16 am

Re: Simple RF transmitter frequency changes

I'll give it a try,

Thank you very much

coolgee6
Newbie Pyro
Posts: 1
Joined: Mon Dec 29, 2014 3:02 pm

Re: Simple RF transmitter frequency changes

I am trying to build a pair which would detect a basketball 70-462 vce
going through a ring,,something like the sketch I've added.
Whats the best way to go about it.I think its pretty guessable what im trying to make. But any help would be appreciated.