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I built my 60-15m QMX last night and initial tests are very impressive. It's built for 12V and puts out 5 to 6 watts on all bands apart from 15m where the output drops to about 2.5 watts. Before I go chasing my tail, is that normal for the mid-band version? My low-band QMX is pretty much even across all bands.

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Cheers,?

Ronan

MM0IVR?

Ronan,

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My mid-band12v unit, built by QRP labs, puts out 5 watts on 15. I have attached the results from their calibration and test result document that accompanied the transceiver that I just received a few days ago.

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I hope this helps!

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72,

Fred/N7PN

Thanks, guys.

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I wound L513 with 12 turns and L510 with 11, as suggested in the instructions. I'll have a play with them to see if I can balance things a bit better. I was still impressed with the initial results before any tweaking.?

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Cheers,

Ronan

MM0IVR?

After a tiny bit of spreading/squishing the turns of inductors L510 and L513, I now have a solid 4.5 watts out on 17m and 5 watts on 15m That's with a regulated 12v supply and a decent 50 ohm dummy load.

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Happy days ??

I built a 9V midband QMX, basically everything works fine and all hardware tests are good, and I used it already for some SOTA activations.

Now I want to tweak it a little, as the power output is good on most bands, just on 15m it could be better. My power outputs are as follows:

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60m : 5.6W

40m: 5.1W

30m: 5.4W

20m: 4.9W

17m: was 4W, now 4.6W

15m: was 3.5W, now 3.7W

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I set the power supply to 9.2/9.3 during rx, then the QMX shows 8.9 - 9.0V during tx.

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Initially 17m was 4.0W and 15m was 3.5W. I played around with the spacing of L510 and 513, but everything I tried did't change much. Then I removed one turn of L513, and 17m improved to 4.6 and 15m to 3.7W. The drop in the LPF sweep moved slightly to the right.

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How did you change the spacing to improve the Output power? Can someone show images of their successful tuning?

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I know that 3.7 to 5W won't be much of a difference on the band, but I would like to get out as much as possible. Especially if others have 5+W on 15m, it should be possible.

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Tks es vy 73 de Robert OE3RLV

Would this rework also apply to the QMX AND the QMX+?

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James

KA9TII

If you are getting more than 5 watts out on any band that you use a lot, then I recommend backing off the input voltage a little to relieve some stress on the finals.?

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73, Dan - W2DLC