I/O Board and Linear amp

F8NDN

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Oct 14, 2023, 1:55:06 PM10/14/23

to Hermes-Lite

Hello,

Here I have a XIEGU XPA125B amp and an ICOM IC-2KL. I would like to know if it's possible to change the bands directly with the I/O board, knowing that the latter works with an 8v command, or if it's necessary to convert?

THANKS

James Ahlstrom

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Oct 18, 2023, 12:45:48 PM10/18/23

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If I understand you, you need a signal of zero to eight volts to send band information. The normal band voltage is zero to five volts. But you can re-purpose the fan voltage to do what you want. It uses the 3.3 volt supply as a reference and multiplies it by 3.7 less Vbe. The final voltage is 3.3 * 3.7 * (x / 255) - 0.65. So it should be stable but will need calibration. Just change the fan speed and see what you get.

Jim

N2ADR

Jim KD4YLQ

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Oct 18, 2023, 7:02:06 PM10/18/23

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Hey Cris,

I like the looks of that XIEGU XPA125B amplifier, nice price too. If you get the I/O board to do the bandswitching properly let us all know - I';m inclined to follow your example. Thanks!