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Phil, are your LPF scans all OK?? Perhaps post a screenshot of one of them.

These also use the tx function, and if they are good, it helps point to the problem.

Stan KC7XE

Also, let us see a close up of the LPF section of your board, top and bottom.

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73, Dan - W2DLC

If you have the same fault in more than one kit, I can't help but think there's something you may be misunderstanding about the instructions.

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73, Dan - W2DLC

Thank you for your advice, guys. I'm away from home at the moment. I'll get some images when I get back. I also have a QDX which works fine. It makes me wonder about T501. The QDX is pre twisted sisters, and was wound standard. Perhaps I've misinterpreted the diagrams. I'll take T501 off and wind it standard and see if that has any impact.

Thanks again.

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Phill EA5JHA

Well that went down like a lead balloon!

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Replaced T501 with a conventional winding for 9v rather than twisted sisters. No improvement, in fact the lpf sweeps are now awful.

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I couldn't screen print with P or T pressed so here is the diagnostic.

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With P pressed BIAS is 30.4mA at 21% duty cycle.PTT on Yellow 0.4V

With T pressed 30.6mA at 21% duty RF output On RED 7.2V 0W SWR 3

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IQ sweep

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RF Sweep

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Receive "was" working on all bands. Plenty of CW and SSB heard. Pin diodes all working, voltages close to zero and 5.88v

I haven't had a chance to try again as I took the antenna down to do some work on the roof!!?

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I'll move on to testing around Q507 but it might be a week or so as I'm off to the UK for a while.

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73

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Phill

Phill EA5JHA

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Phill EA5JHA

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Phill EA5JHA

Phil,

The resolution gets reduced quite a bit here, but once you redo T501, I would resolder the pin diode connections. Some of them look like the possible cold joints. Also, It's hard to tell for sure, but it looks like there may be a little whisker of solder shorting the center to ground of the BNC connector. Soldering all looks pretty good on the LPFs.?

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73, Dan - W2DLC

Thanks for the advice, Dan.

Well, I'm quite surprised. Retouched T501 again, no change. Checked Q507 traces, all OK, pins to pads OK.

I couldn't see anything wrong in that area so I heated up Q507 and added some solder to the connections. Weird, all now works!?

Power is a bit down, ranging from 0.8w on 6m to 4.5w on 80m. Probably some coil squeezing to do!

On 9v rx is 135mA and tx is 830mA all running cool on wspr 40m 3.7w into the dummy load.

Thanks to all for the excellent advice.

Phill EA5JHA

Excellent!? Glad you got it working!

As for power output on the upper bands, I think the 'twisted sisters' winding helps with that, making the transformer more efficient.? But if it is already enough for your needs, I wouldn't change anything.? Just enjoy it!

Stan KC7XE