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Showing posts from February, 2018

### Reducing CW Key Errors in uBITX

Reducing CW Key Errors in uBITX

uBITX uses ADC to distinguish CW Keys.
Unmodified uBITX uses A6 of ADC I / O as CW Key input.
The A6 is connected to 5Volt with a 4.7K ohm resistor.

The Arduino ADC has a value between 0 and 1023.
As shown in the figure above, A6 is connected to 5Volt at 4.7K, so you will get a value of 1023.
1023 / 5 * 5(input) = 1023

If you press the straight key, A6 will have a value close to zero.
1023 / 5 * 0(input) = 0

To use Paddle with uBITX, we need to use 2.2k and 10k resistors.

When press the Dot key of Paddle
5 * 2.2 / (4.7 + 2.2) = 1.594
1023 / 5 * 1.594  = 326

When press the Dash key of Paddle
5 * 10 / (4.7 + 10) = 3.4
1023 / 5 * 3.4 = 695

When both Dot and Dash are pressed 5 * 1.8 / (4.7 + 1.8) = 1.3 1023 / 5 * 1.3 = 265

The above values are ideal values.
In actual use, errors occur in the measured value due to the error rate of the resistance, the length of the wire, and the resistance of the key contact.
Therefore, we use a wide range of values as shown b…

### How to use Wsjtx-Portable (Wsjtx 1.8.1 based Small LCD version)

How to use Wsjtx-Portable (Wsjtx 1.8.1 based Small LCD version)