HELP RF 433MHz Serial Communication not reading

I am using a SparkFun RedBoard Qwiic and I am trying to transmit and receive messages between 2 Arduino. I am using this: RF 433MHz Transmitter/Receiver Module With Arduino | Random Nerd Tutorials as a guideline.

The first time I tried at home, I have both boards plugged in like so:

and the transmitter was sending messages to the receiver, and I was able to read the messages through the serial port like so:

However, the second time I tried it at school, it stopped working. With the same setup and same code, there was no message being read through the serial communication.

So to test whether the transmitter and receiver are working or not, instead of data being transmitted to the pin, we made it so data is transmitted to the LED light like so:


and the light is blinking to show that the receiver is receiving stuff from the transmitter.

does anyone know what's wrong? Why is serial communication not reading the messages? And nothing has changed but it worked the first time and not the second.

It would behoove you to attach antennas to your radios. :slight_smile:

It worked without having to use antennas before.

But now, it isn't.

Yes, but I thought antennas are only necessary if it is further away, the two are back to back, antenna wouldn't make much of a difference no?

Motorist: My engine makes funny noises.
Mechanic: You're missing a wheel.
Motorist: I drove here, didn't I?

Try it and decide. Solder straight wires, 17 cm long to the ANT pins.