"I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power output as discussed here."
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It generates slight RF noize. Which is annoying.?
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Subject: [QRPLabs] QMX+ with 100 amp/hour lithium iron battery;
10.04.2025, 21:13, "Tom - AJ8X via groups.io" <tom.metty@...>:
I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power output as discussed here.
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In hindsight, I like the adjustable buck-boost idea to solve both problems.
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