I only need one way traffic, to send command to an Arduino.
PC->usb->rs232->Max3223->ttl->txc1->433mhz->rxb1->RX->Arduino.
I'll end up using python to send to the com port.
In my tests I have it the other way round.
Arduino->TX->txc1->433mhz->rxb1->Max3223->rs232->usb->Hyperterm
I'm not sure what the LOS distance is, I expect antenna design impacts that greatly.
I have it working from one side of my desk to the other. 