AM transmitter output stage!

[omidi_sbu]

I have assembled an AM transmitter(--> a variation of https://www.electronics-lab.com/projects/rf/011/index.html) but the output power is so low that i cannot receive anything on the raido. how is it possible to add a power stage at the output?

output charcteristics:
Vcc=14
Vop-p=10 (large signal)

VoDC=12

 

[the_risk_master]

Hi

Can you post the circuit here?

 

[sinip]

I have assembled an AM transmitter(--> a variation of h**p://www.electronics-lab.com/projects/rf/011/index.html) but the output power is so low that i cannot receive anything on the raido. how is it possible to add a power stage at the output?

output charcteristics:
Vcc=14
Vop-p=10 (large signal)

VoDC=12

If you can't receive anything on the radio that could mean:

1. The oscillator is not oscillating. Check elements and assembly.
2. You are not listening at the right place. It works on medium wave (MW / AM) and not on FM.
But you definately DON'T need power amplifier to be able to receive it in the room.

 

[omidi_sbu]

The transmitter has a 450KHz (slightly below AM range ) oscillation frequency and enough modulation percent. (checked with iscilloscope)
the receiver works well (on other stations). when the reciever is tuned to the transmitter frequency and i put them next to each other i can hear the sound on the receiver (but weak)...
Here's the schematic.
(the values may be a little different!)
How can i mesure the power of this AM tranmitter?
how much power is needed for a 10-20 meter transimission.
(i don't know how to make the picture show up here and no download needed!)

 

[sinip]

The transmitter has a 450KHz (slightly below AM range ) oscillation frequency and enough modulation percent. (checked with iscilloscope)
the receiver works well (on other stations). when the reciever is tuned to the transmitter frequency and i put them next to each other i can hear the sound on the receiver (but weak)...
Here's the schematic.
(the values may be a little different!)
How can i mesure the power of this AM tranmitter?
how much power is needed for a 10-20 meter transimission.

You can measure the output or at least get a general picture of it if you make some simple RF field meter. You need analog instrument, diode, capacitor and small antenna (piece of wire). It will show you the field strength. If the transmitter works on 450kHz it might get directly into IF stage of AM receiver (which is usually 455-460kHz). Try to put it up to real MW range and see what happens. Other than that the schematic looks a bit strange, regarding that feedback coil to emitter of BC109 but then again it might be ok as well. Could not tell before I make it myself. ;-)