Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

how to increase FM transmitter output power?

Status
Not open for further replies.
Most of these FM projects have a very sad antenna. You can get gain from a good antenna.
 
going back to the darlington thing for a moment, a darlington has a beta (current gain) of (betaQ1)*(betaQ2). so for a darlington made with a pair of 2N3904 transistors with a beta of 100, the beta becomes 10,000. the miller capacitance is beta times BC junction capacitance (which for a 2N3904 is 8pf). so, the darlington would have a miller capacitance of 10,000*8pf or 80nF, which has a reactance of 0.02 ohms at 100Mhz, which means the RF bypasses the base almost completely, and the transistor will not amplify it.

as for efficient antennas, google "j-pole antenna". a very efficient antenna is a better solution than an amplifier. an amplifier uses power, dissipates heat, and can be very cranky about it's load (as well as generating unwanted harmonics that can get you in deep doo-doo with whatever alphabet agency governs the airwaves in your country).
 
i hav never got any helpful reply from u ignorant man..why dont u go and play with a 1.5v battery and some Leds? ..u r the real stupid as u never ever post ur own comment but repeating on one's comment

haha nobody can compete with Ziddik to quarrel. I've seen some other commets too :D
 
Last edited:
shame for some the comments as there is some realy good info in here. i have a question regarding attena's i assume they are a fixed lengh dependent on frequency is this correct?
 
i have a question regarding attena's i assume they are a fixed lengh dependent on frequency is this correct?
Yes.
A single whip antenna with a ground plane below it like on a car should be 80cm long at 100MHz. Then its length is 1/4 wavelength.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top