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Morse code is often associated with traditional receivers having finite bandwidth typically a few kHz. I can remember many years ago receiving Morse code on a Short Wave receiver sometimes on it own and sometimes in the background of transmissions like “The Voice of America” or “BBC World Service” So back then I didn’t think much of it.
Receiving and processing SAQ Grimeton’s Christmas message 2023, I now realise that there is a lot more to Morse code and I’m surprised that it is not used more often.
Most likely this is well known to others and I’m just catching up. The logic goes as follows:-
1. Carrier Wave (CW) has virtually zero bandwidth. When modulated by Morse code (essentially a binary CW on or off) the bandwidth is still very narrow.
2. Therefore all the power of the transmitter is concentrated into that one frequency Carrier Wave (no side bands, no spread or channel width).
3. When SAQ Grimeton transmits it is as sharp as a needle in the VLF spectrum.
4. Consider a simple modern receiver with analogue resonance at SAQ frequency of 17200 Hz. Already most other frequencies are suppressed.
5. Now record the analogue receiver CW output using a high quality computer sound input at 48000 samples per second or better.
6. Now process this recording using modern digital processing digital filtering methods, what is left is only the SAQ 17200 Hz carrier in the middle of a very narrow bandwidth typically as low as 40 Hz.
7. Shifting the Carrier Wave pitch digitally to 750 Hz renders the Morse code audible.
So with a well constructed analogue receiver front end and followed by computer recording and processing the Morse code can survive all kinds of noise including lightning storms. Without tests I can’t say but my opinion is that SAQ Grimeton can be received and understood anywhere around the globe.
Surely Morse code should be used far more often in today’s digital world!