Problem regarding cansat (APC220)

Me and a few class members are doing the cansat project (we have to build a satellite that is the size of a can). For that we use technology from Arduino. We have two APC220 transceivers, one that will go on the satellite and one on our 'ground station', and we are trying to have them communicate with eachother. Both are connected to an Arduino Uno board. We now need to run a test, to see whether or not they actually communicate. The codes that we need for that were already given to us and should work (we also verified them all and there were no writing mistakes found). We have an instruction book that tells us exactly what to do. We followed all the steps through multiple times, but our two transmitters still do not communicate with each other.

The instructions tell us that for the test we first need to connect our arduino uno board to our computer and upload a pre-made sketch. Then we need to connect the first APC220 to our board. On the serial monitor we should see a series of increasing numbers. All of that works, the numbers are displayed. We now need to disconnect the arduino from our laptop and power it by battery. The battery works, so that can't be the problem, but we can't check if the numbers are still being transmitted. Then we need to connect our second transceiver to the second Uno, connect that to our laptop and upload another pre-made sketch for our 'ground station'. We should now be able to receive the numbers that the first transceiver should be sending and see them on the serial monitor. We've done this whole process multiple times, we've switched our transceivers, we checked all the codes, but we have never received the test data.

What could be wrong? What should we check? Are we missing something?

Thank you in advance.


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