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QCX mini - converting from 20m to 40m

#20m #40m #qcx20mini

Ted 2E0THH All Messages By This Member #74696 After a year on 20m,? I have decided to convert my Mini up to 40m.? This looks very straight forward as the toroid cores are the same, just a question of rewinding them all appropriately. On the caps, I think I might just just snip and break the ones that need to be replaced, then solder the new caps onto the old legs. The hope is this will save the PCB pads and this would also allow a much easier band change in the future, if I ever go there. I briefly considered using PCB pins for both the caps and toroids, but it is probably now both perilous to the PCB and complete overkill. I might have considered it on the initial build.? Has anyone else converted bands on their QCX? 73s Ted 2E0THH
Julian N4JO Member Profile All Messages By This Member #74698 Converting bands is, practically speaking, no different to replacing faulty components. You've already addressed the concerns, and suggested perfectly valid mitigation strategies. Go ahead as proposed :-) -- Julian, N4JO.
Ronald Taylor All Messages By This Member #74705 Hi Ted. Yes I have done this. Since you are going down to 40 meters, don't forget to also add the 39 pF (390) capacitor in position C5. It won't have one there for the 20 meter version. You got one in your kit if you still have it around. And yes you have to rewind all the toroids ihcluding L4 and change C30 from 30 pF to 56 pF. The normal BPF and LPF adjustment procedures should get you right back up and going .... Good luck ... Ron toggle quoted message Show quoted text On Mon, Nov 15, 2021 at 8:04 AM Ted 2E0THH <qrp@...> wrote: After a year on 20m,? I have decided to convert my Mini up to 40m.? This looks very straight forward as the toroid cores are the same, just a question of rewinding them all appropriately. On the caps, I think I might just just snip and break the ones that need to be replaced, then solder the new caps onto the old legs. The hope is this will save the PCB pads and this would also allow a much easier band change in the future, if I ever go there. I briefly considered using PCB pins for both the caps and toroids, but it is probably now both perilous to the PCB and complete overkill. I might have considered it on the initial build.? Has anyone else converted bands on their QCX? 73s Ted 2E0THH
Ted 2E0THH All Messages By This Member #74717 Thanks Ron I managed to lay my hands on 2 HROs recently so the first Christmas job will be to get those recapped and realigned. I've run out of magnet wire so just ordered a selection on bobbins from Banggood, And you are quite correct, I still have that 39pF! 73s Ted 2E0THH?

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