Im trying to create a simple QPSK modulator and demodulator in GNURadio using a hackrf and pluto SDRs. Im trying to modulate and send a file containing "1234" over to my other device and demodulate it, saving the results to a file anticipating seeing "1234" on that side. Im having issues with the decoding portion (im assuming?) as you can see, im getting a stream of random characters the program is not properly decoding. Im not sure if there is a step im missing such as an unpack/pack or maybe issues with the parameters of my other blocks. Any help is appreciated!
I tried to modulate a file containing "1234" and send it over one SDR, receiving it on the other and demodulating and decoding. Expected to see "1234" in the output file but instead saw an array of incorrect characters
You have no framing– the receiver simply can't know where one byte ends and where the next one starts.
Furthermore, at 2.4 MHz bandwidth, your channel isn't flat anymore, so as soon as you do more than just repeating the same pattern all the time, you'll need an equalizer, or to use a method of transmission that inherently removes the multipath problems, which usually means you go for OFDM.