I ordered the 433mhz 2km long range RF kit, and I can’t even get it to work on the demo project pictured on breadboards. Is there some big secret to getting these things working? Much of the documentation instructs to apply 9v to the power input, but I later see a post saying this was wrong, to only apply 5. Could it be that this mistake has somehow damaged my boards?
It should not be damaged , it can be supply 5-9V.
You can connect like the manual on wiki, and do not put RX and TX too close when test.
How close is too close? I did the wiring and saw no output on rx.
At least they are not on the same breakboard , it is better above 1 meter.
Can you provide the picture that how you connect them?
Others, check if the Crystals of transmitter is 433Mhz .
I have a +5V (sometimes tried with 9v battery) wired to the input on the TX module, along with any one of the inputs for the purpose of providing constant pulse for verification. I have a ground to well, the ground.
On the RX breadboard, I have +5/+9v to voltage input, ground to the ground pin, all the outputs for the sake of testing to the same rail on the breadboard, an LED to ground for the sake of illuminating as soon as I have any kind of output from RX.
Currently, all of the addressing pins are not soldered at all to anything, as I believe the documentation states are “floating”.