When you use your mind for conscious Morse decoding, you can do well at lower speeds. But you run out of brainpower as speeds increase.

Before I write my articles about using a Windows PC to decode Morse, I thought I would dig into manual decoding with our wet-ware. Just how does the brain decode CW? We will split the discussion in two parts. First, consider the conscious mind.

At its core, Morse is a time pattern with four symbols: dot, dash, element space and word space. If Morse code was synchronous (clocked) dots and element spaces would be one tick, and dashes and word spaces would be 3 ticks.

But human-sent Morse is asynchronous, and the sender must use an imaginary clock to get the timing and ratios correct. This is what makes computerized decoding (bit detection) so darn hard. But brains seem to handle this instability much better than your PC.

Whether you think in dot-dash, dit-dah or on/off, conscious Morse decoding means you need to do low-level decoding of the four symbols as they pass by, or more specifically, through your senses. And, since there is no internal clock in your brain, you have to make one up.

Studies have shown that conscious Morse Decoding begins to fail at 25-30 WPM. Let’s find out why.

Conscious Morse Decoding – A Matter of Timing

First, consider response time. Your consciousness will respond to an auditory (Morse signal) stimulus in maybe 200 milliseconds. So, in effect, your conscious mind will be taking data out of a delayed buffer.

Second, let’s look at symbol discrimination. Typical Morse timing for a “dit” ranges from 60 milliseconds at 20 WPM down to 24 milliseconds at 50 WPM. On the human side, the conscious mind has interval discrimination of around 25 milliseconds, which can improve to 10 milliseconds with training.

Third, let’s consider information processing. Your conscious mind can process about 60-70 bits per second. Typical Morse code runs at 15-30 bps.

When you consider these three facts, and add in consideration for SNR and distraction, as Morse speed increases, you are putting your conscious mind under increasing pressure to buffer, discriminate and process incoming code.

This explains why attempts to get good at low level decoding higher WPM will only get you so far. What’s next? Here are a few clues. Conscious mind is only 5-10% of your brain power. Your subconscious mind, on the other hand, can handle millions of bits per second and respond in milliseconds.