@Michael VE3WMB , When building my QDX v2, I also found that 20 cm was too short. After doing 60 full turns, I was only able to get about 8 turns of the trifilar wire wound around the toroid core. Unf

#transformer #qdx

It just occurred to me that my twists were 360 degrees (i.e. a full revolution of the screwdriver used as a grip). If the intent was to do 180 degree twists (which might make sense) then I would ended

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The old hand drill for winding transformer wires is an excellent idea as it is slow enough to allow more control than even my best electric drill. I have my fathers, step fathers and my grandfathers o

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For my last trifilar winding (for the QRP-Labs receiver module), I put one end in my bench vise and did the winding with an antique hand drill (I think it was my grandfather's). I plan to do the same

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I finally completed my REV 1 QDX yesterday and made my first QSO with it on FT8. My only build issue was with T2. I measured three 20cm lengths of wire for the trifilar winding and twisted them for 50

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I too use a variable speed drill with a small screw eye bolt to attach the wire ends for winding. As Jim said, it works well and is easy to keep the turns consistent. 73 Evan AC9TU

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I have a cordless electric drill that I use for making twisted windings. It works very nicely on nearly every size wire, and getting even twists is very easy and very repeatable. 73 Jim N6OTQ Sent fro

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FWIW--for the last two or three wire preparations (of either bifilar or trifilar), the stationary ends were put over a pencil taped to the desk per Hans' manuals. At the other "to be twisted ends", I

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I agree, Alan. I've built a couple with 50 complete turns, and IMO that's quite tight enough, and not too difficult to unwrap an straighten when it's time to solder the connections. I do find it helpf

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A larger core will mean more inductance so normally fewer turns. A guess, it would probably not matter in this broadband transformer application. Hans says it is not critical, I just turned mine until

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Oh well... 0.5mm's not going to fit 10 trifilar turns on the ft37-43 :-) Looks like best option is to order some 0.33mm/28awg, which I will go ahead and do. (probably) crazy question... I have an ft50

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Thanks Julian, for the help and quick reply! I'll try it out and if I have trouble cramming it on, I'll order some smaller wire :-) W.

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It's a coupling transformer, not a tuned circuit, so f you can get it on the toroid, it'll work.

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Hi All, Enjoying my build of a rev2 QDX very much! Thanks Hans for a great kit! But... :-) I was too generous with the 28awg (0.33mm dia) magnet wire on the low pass filter section, and have found mys

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Thank you all for your help troubleshooting. I can't say exactly what the problem was. Alignment menu 8.7 BPF value suddenly jumped to 08+ bars. I was able to complete the alignment (BPF, IQ, Lo, Hi).

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John: I just looked at your photo -- the solder connection in the center of L2 looks suspect. Steve N9SZ

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John: Sounds like you have an enamel removal/soldering issue with your LPF toroids. Steve N9SZ

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Update: 1. I found a solder bridge shorting the RF output. But BPF output is still low (05) 2. I used a resistor in parallel with R43 (as explained int the troubleshooting guide). See photo here: http

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John, 2as C1 fully to the left, or fully to the right? You should be able to peak at 8 and about half-scale bars. 4 is way too low. 73, Shane KE7TR

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The troubleshooting guide says "If the signal strength is less than 7, or if there is no peak, then it is necessary to investigate further." See https://www.qrp-labs.com/qcxmini/trouble.html.

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