Re: simple receiver
Here is the general receiver layout. From left to right (the standard way to draw scnematics or block diagrams indicating the signal flow.) antenna input, band pass filter, diode in series, load RC network in shunt, low power amplifier to get the 10 ms pulse, comparator to detect the pulse and produce a logic level to trigger your transmitter.
If you do not have any RF experience this may be more difficult for you but you can still do it. For best performance you will need some expensive test equipment. As a first try, put a wire to a diode in series and put this to your oscilloscope input. See if you can see the pulse. There should be a 200 ohm or so resistor from the node between the diode and the wire to the ground node.
Do not be surprised if you get some of the local AM broadcast stations. This is the reason for the band pass filter in the real design.