4 Watt FM Transmitter

[Cerium]

I am working on putting together this transmiter. I heard Sasi talk about removing the microphone imput for cd player use. How might I go about doing that? Thanks. 

 

[audioguru2]

Hi Cerium,
That 4W FM transmitter doesn't have pre-emphasis (treble boost) like radio stations have, so its received audio won't have much treble. Its received audio will sound something like an AM radio or like your stereo with its treble control all the way down.

You can mix the stereo output of your CD player into mono and reduce its output level with a 47k resistor from each of its two channels to C2 without using the TR4 stage.

You can add pre-emphasis by connecting a 2.2nF capacitor in parallel with each 47k resistor for Europe and Australia. Use 3.3nF for North America. ;D

 

[Cerium]

So would this be correct. The resistor and capacitor in the box are the ones you specifyed.

 

[audioguru2]

Hi Cerium,
You must get rid of TR4 and R2 and the rest of the mic preamp so it doesn't load down your external input.
Don't you want the stereo input to be combined into mono like this?:

View attachment 37464

 

[Cerium]

OK... Cool, that makes sence. Thanks a bunch. 

-Cerium

 

[Cerium]

I was looking for all the parts and the 2n3553 transister is quite hard to get hold of. Could someone please help me find a more current transitstor that will work. Thanks again, Cerium

 

[ohms]

SHALL I REPLACE WITH 2N2219 WITH 2N2219A FOR T1 AND T2?ANYBODY CAN CLARIFY?

 

[Alun]

If your CD player has a treble control you could save yourself the bother and turn it up to maximum. ;D

 

[sneaker73]

Hi Cerium,
You must get rid of TR4 and R2 and the rest of the mic preamp so it doesn't load down your external input.
Don't you want the stereo input to be combined into mono like this?:

Got a mod for the 15W version to do stereo input?
http://electronics-lab.com/projects/rf/014/index.html <-- this 1.

 

[shahzad-h]

HI,Cerium

I was looking for all the parts and the 2n3553 transister is quite hard to get hold of. Could someone please help me find a more current transitstor that will work. Thanks again,

here's the substitute of2N3553
{BFW47,BFS23,BFS22,BLY34,2SC2419,2N3924,}

 

[DjAngelo]

Hi!
May I have the component list of this schematic?

I belive is dofferent from this 4 watt fm trasmitter http://www.electronics-lab.com/projects/rf/021/index.html

 

[mettula]

u can make the veronica - it has a preemphasis network and a pll so it is very stable fm exiter, it only needs an rf power amp if there is any volnteer.....

veronica_1w_pll_pro_transmitter.rar