FM Transmitter | Electronic Project Circuits

Posts Tagged ‘FM transmitter’

15W Fm-transmitter

It was five years ago when I did an attempt to build my first fm-transmitter. It ended in a giant faillure. The only thing it did was interferring with our tv-set. Looking back it was due to the lack of information I had. A schematic was my only help. Now, five years later, I know a lot more about electro-technics. So I searched for a schematic of a stable, tested fm-transmitter with a far reach. I will put all information you’ll have to know in my page. I made drawings to make things clearer. As said before: I’m still building it, so I will add information every time I made progress. It would be wise for you out there not to start building untill I’m ready and have tested it. It has been succesfully built before, but my succes will give you a double security. I remind you of the fact that I can also fail.

Source:http://www.electronics-lab.com/projects/rf/014/index.html
Thank you.

Be the first to comment - What do you think? Posted by admin - January 22, 2008 at 10:22 am

Categories: FM transmitter, RF-Radio Frequency Tags: FM transmitter, RF-Radio Frequency

V7 VHF FM Transmitter by 2N3866

The circuit is identical to the V7 VHF FM Transmitter but with a few small additions. TR1 (BC547) is an inverted Hartley oscillator which based upon an inductor fabricated on the PCB. This makes it megga-stable, and setable anywhere in the VHF FM band (76MHz to 119MHz) and the BB105 varicap makes it voltage tuneable over about 8MHz of that band. The inductor has one tapping for feedback and a second to feed an optional prescaler. TR2 is a buffer/amplifier and TR3 it the PA stage.

Read More Source:http://www.next.gr/rf/fm-transmitters/index3.html
Thank you.

Be the first to comment - What do you think? Posted by admin - at 9:48 am

Categories: FM transmitter, RF-Radio Frequency Tags: audio fm transmitter, FM transmitter, rf transmitters

FM TRANSMITTER one Transistor by 2N3564, 2N5225

A truly minimalist circuit. Performance is relatively poor and stability is a problem. Q1 modulates the signal and acts as an oscillator. L1 and C5 determine the frequency. Decrease C5 for a higher frequency and vice-versa.

You won’t get a long range transmission with this one. The author claims 50-500 feet. A lot depends on the antenna. It must be made of stiff wire or else the frequency will change as you move the antenna. Experiment with different lengths to get the maximum range. 50cm or less should work reliably most of the time. A longer antenna might give even better range but if you exaggerate, the circuit will begin to oscillate and performance will drop dramatically. A regular telescope whip should work, too.

Part
R1 27k
R2 56k
R3 12k
R4 100
C1 1u
C2, C3 470p
C4 6 to 10p
C5 1-30p trimmer
L1 etched on PCB or a center-tapped coil 5mm in diameter, 6-8 turns of enamel-coated wire 1mm thick
Mic Electret microphone
Q1 2N3564, 2N5225 (other general-purpose NPN transistors will work, too)