I have been working with Mike Johnshoy, KB2ML, on the sBitx 64 bit development. For straight keying I use a test setup of the DUT transmitting at low power into a dummy load with another receiver (K3) monitoring the signal with a short test antenna (a jumper lead clipped onto a PL259 center) located on the dummy load.. The audio is recorded in Audacity and the waveform analyzed by a Python program that detects peaks, times signal and spaces and does some statistics on the results. I drive the DUT with an external keyer to produce a string of perfectly spaced dits. Here is what the 64 bit code waveform looks like in Audacity for dits at 40 wpm.
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and here are the stats for this sample:
Number of dits 24
Number of spaces 23
Average Pulse Duration: 0.043156 seconds
Standard Deviation of Pulse Durations: 0.003587 seconds
Average Space Duration: 0.041293 seconds
Standard Deviation of Space Durations: 0.003424 seconds
Cycle length: 0.084448 seconds
dot/sp: 1.045122
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Now lets look at the same 40 wpm test with the zBitx running 1.06/3.52
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and after backing off to about 15 wpm
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The results are so irregular that I couldn't run any analysis.
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This confirms for me the difficulty I had in sending with a straight key with the zBitx.
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The zBitx internal keyer looks pretty good but I, like others, find Iambic B mode to have serious problems.
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??? Bob? KD8CGH
Bob Benedict, KD8CGH