Email from source:
Topic: transmitting digital information via FM radios
After I read this I realized how much I SHOULD have known about how data (FLDIGI) audio is different from human speech in an FM radio.
Please read this doc. It explains so much about the concept of "deviation" and "pre-emphasis" of the treble tones in the transmitter and then the complimentary "de-emphasis" of the treble tones in a FM receiver.
It also explains how over driven audio just kills the data transmission.
It is written about PACKET but all of the FLDIGI modes apply as well.
It does not apply to HF SSB rigs, but I thought it might be of interest.
Let me know what you think of this paper
PaNBEMS
https://www.febo.com/packet/layer-one/transmit.html
Topic: transmitting digital information via FM radios
After I read this I realized how much I SHOULD have known about how data (FLDIGI) audio is different from human speech in an FM radio.
Please read this doc. It explains so much about the concept of "deviation" and "pre-emphasis" of the treble tones in the transmitter and then the complimentary "de-emphasis" of the treble tones in a FM receiver.
It also explains how over driven audio just kills the data transmission.
It is written about PACKET but all of the FLDIGI modes apply as well.
It does not apply to HF SSB rigs, but I thought it might be of interest.
Let me know what you think of this paper
PaNBEMS
https://www.febo.com/packet/layer-one/transmit.html