1km am transmitter

Hello friends,
I am trying to design Transmitter & Receiver which they satisfy 1km range for remot controlling, also i want the transmitter size is as small as possible to fit in embedded system.
About me it is ok to use VHF or UHF bands, so can anyone advice me for schematic circuit or ready modules? Also, please advice me about the antenna, how i will deal with it to transfer maximum power?
Note that my transfer rate needed is low about 100-500 bps.

Thanks

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