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!.
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!.
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
Enter in a search on Google: Stereo Micromitter and the 1st link will be to Silicon Chip magazine's stereo FM transmitter project.
I've seen finished ones in stores. For only $25.00CAN on sale. They have an RF attenuator on the output which can easily be bypassed for greater range. :lol: