I have quite a few so I decided to post many FM transmitter schematics.

Attached Thumbnails

     

 

What about component values in the first schematic? "fmtrans2.gif"

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sorry about that...

I got them somewhere here in about 50 megs worth of my personal garbage :? .

 

will this circuit design work if i go by your diagram?(the 2nd one)

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it should work as long as you follow the schematic closely and dont use a breadboard or stripboard

use a pcb as the metal tracks breadboard and stripboard tend to act like many little capacitors, causing the radio to not work properly

i hope that answers your question...

 

Isnt the last circuit an AM receiver? I found it from CXI (Circuit exchange Intertnational) schematics.

I recommend the 2nd circuit as an FM transmitter since it worked for me.

 

yes it is lol...

i have about 200 circuit schematics and about 120 of my own...gets mixed up alot...

sry

 

how do I calculate the bandwidth each transmitter delivers?

 

I don't think you do, although suprisingly effective these types of transmitters are horribly crude - the more audio you put into them the higher the deviation of the output. It's not even a 'proper' FM modulation, I suspect you probably get as much AM as FM from them?.

But any FM transmitters bandwidth is dependent on the amount of modulation applied - that's why broadcasters have serious limiters on their inputs!.

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ok

how do I calculate the modulation level, and what are the units for the modulation level?

 

Again, I don't see how you can, the modulation action in these crude transmitters is obscure in how it works, I see no way to calculate it.

For an FM transmitter I imagine it would be measured in 'KHz per volt', or something similar?. For an AM transmitter it's in percent.

Why do you want to calculate/measure this anyway?.

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I want to be able to make my own wireless network between two computers, and further learn radio electronics.

 

This isn't the way to do it!.

It's far too low a frequency, and far too low a potential data rate for networking.

Wireless network components cost very little these days and give excellent speed and performance - you would probably spend more building crude radio systems for a system more than a thousand times slower!.

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these are not for those kind of uses.
these are simply the basic design for audio transmitters, not data transmitters.

like nigel said, they are too low of a frequency and would get far too much interference and data loss. if you are really interested in learning about radios, the best way would probably be to buy a good-quality diy kit

i hope that helps...