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Re: QMX LPF for [40m/30m] - Version 1 measured results


 

Hi Nick,

I¡¯m interested in your filter design. I¡¯d like to Spice it for comparison. Do you have a schematic available?

Thanks,

Tony - AC9QY

On Tue, Sep 19, 2023 at 11:59 AM Nick G4IKZ via <nds12321=[email protected]> wrote:
Encouraged by the results of the [80m/60m] filter I implemented my [40m/30m] filter to go with it. The attached VNA sweeps include the LPF both diode switches and the coupler. I was about to measure Tx harmonics when I dropped a crocodile clip on the back of the PCB. I guess there's a law about these things but it landed across the 12V DC input jack and the 5V Vdd pin. Entirely my fault but fireworks and a fried QMX as would be expected. So no more work on this, but if anybody wants details of either LPF just let me know.

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