27MHz carrier signal using a oscillator chip or with few transistors alone

[Kovardhani]

I am trying to generate a 27MHz carrier signal to transmit it through a loop antenna, I referred many circuits couldn't able to find the one I need. can anyone guide me on generating it using a few simple transistors or using an oscillator chip with a 3v cell battery? The thing is my design is going to be very small, so I don't want to use transformers to overtone the crystal oscillator. is it even possible?

 

[Dick Cappels]

Leave off R1 and the microphone, then change C4 and L1 to resonate at 27 MHz, and you will have an unmodulated carrier.

Choose and inductor of about 1 uH for L1 then calculate the necessary capacitance.

 

[Kovardhani]

View attachment 131742
Leave off R1 and the microphone, then change C4 and L1 to resonate at 27 MHz, and you will have an unmodulated carrier.

Choose and inductor of about 1 uH for L1 then calculate the necessary capacitance.
View attachment 131744

Okay, Thank you. will this circuit work on 3V?

 

[Dick Cappels]

Probably
Make sure you leave off the microphone because it won't work from 3V.

You will probably find that you will need to remove R3 and perhaps experiment with R2.

What will you be using to detect its output? I used a transmitter like this on the Citizen's Band back when CB was a "thing", but nobody could copy me for more than a few seconds at a time because the transmit frequency drifted constantly and the receivers had fairly narrow (8 kHz) bandwidth.

 

[schmitt trigger]

To continue to bias the transistor in the linear region with this lower battery voltage, change R2 to 7.5k

 

[Kovardhani]

Probably
Make sure you leave off the microphone because it won't work from 3V.

You will probably find that you will need to remove R3 and perhaps experiment with R2.

What will you be using to detect its output? I used a transmitter like this on the Citizen's Band back when CB was a "thing", but nobody could copy me for more than a few seconds at a time because the transmit frequency drifted constantly and the receivers had fairly narrow (8 kHz) bandwidth.

I haven't really given a thought about the detection part sorry, I will experiment with it and will let you know.

 

[Kovardhani]

To continue to bias the transistor in the linear region with this lower battery voltage, change R2 to 7.5k

Okay, Thank you!

 

[Dick Cappels]

If you can use a broad band or untuned field strength indicator it will probably much easier for you to get the transmitter working. When using this circuit on the FM band, I will slowly bring my fingers to and touch the coil. This will, if the oscillator is working, cause the carrier to sweep downward giving me an idea of where the transmitter is tuned with respect to where my receiver is tune.