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20190216 - Home brew Adventures

posted Feb 15, 2019, 4:29 PM by Onno Benschop   [ updated Feb 15, 2019, 4:30 PM ]
Charles NK8O shares with us his activities this week:

Four State QRP Hilltopper 20, modified for 30 meters, display added.  Custom offset at 600 Hz instead of 800 Hz.  Several other code additions, including tuning steps of 500 Hz, 100 Hz, and 10 Hz.  Tones notify which step, 3 dits = 500 Hz, 2 = 100 Hz, one = 10 Hz.  Still need to devise a case for this chimera.


40 meter bandpass filter, first of several.  Needs connectors and testing for bandpass edges, in-band and out-of-band attenuation.



HamRadio Workbench Dummy Load, with modified code.  Resistors sufficient for 20 watts, briefly.  Scope was connected to plot actual PEP voltage against ADC output.



Diode output and ADC in the Arduino are far from linear.  This is correct at about 5 watts but not so much at 1 watt or 10 watts.  Maybe a look-up table would be a better solution?

#nk8o #hilltopper#qrp #homebrew
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