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Thank you very much, Hans, for running that test! It shows the commutating diode as a viable option for those who feel it can provide them benefit. I think that staying within the

Hello Hans, what's the planned ETA for the PTT output fix? 73 Hari OE6HKE

Hi John In the attached "before" and "after" scope screenshots the top trace (blue) is RF output across a dummy load, the bottom trace (yellow) is a BS170 Drain voltage. "After" has the 1N4148

An excellent follow-up, Steve! Sort of the TLDR; of Jerry Sevick's book :-) JZ wrote:

John Z has some good advice but don't drive yourself crazy for ideal hard to achieve super neatness. The transformer will do just fine if you follow directions. Transmission line transformers, where

Most likely hardware. Either the encoder pin connections or the header/pin connection. -mike/w1mt

Hans, That is a very good experiment! I can see though that it will have the QRPp crowd rushing to make the power supply separation mod! :-) It is clear that avalanche is occurring as you describe

I haven't soldered anything to the board, just plugged in the usb micro lead, so I've submitted a ticket. Thanks for all your replies! Great forum this. Regards, Roger.

Hi JZ, all I had an idea that it would be interesting to snapshot the drain voltage spike at various different supply voltages. Normally the QDX won't operate properly down below somewhere around

I tried the same yesterday, It is a pending fix, PTT doesn't work. I found a thread on the Forum. 73 Ian G4GIR

One more image, this one from the OnSemi datasheet for BS170: Both Vds and Vdg are never to exceed 60 Volts. Note the damage warning at the bottom. We don't expect every BS170 to fail at these

Hello Chris Not at all Chris! Neither upset nor offended. I agree with much of what you said and constructive criticism should in any event, always be welcomed.

Has anyone tried running a 50 watt power amp with a QMX? I tried, but the red LED does not light up and there is no 5 volt voltage at the QMX output.

Evan, Thank you for those suggestions! ?Yes, I plan to scope the IC5 with the BS170’s removed. I’ll report back once the surgery is complete… 73, John

Hi JZ, all If you are using the conventional transformer in a QDX/QMX and it is working well, I would not suggest changing it. However to be quite clear - there was a parasitic resonance problem

Thanks for your patience, Hans!

Hi Paul Please see http://qrp-labs.com/shipping.html#collecting 73 Hans G0UPL http://qrp-labs.com https://buymeacoffee.com/g0upl

I would say the proper tack is to verify that Q11 is functioning properly. If Q11 weren't taking its share of the load, that would leave Q9 doing most of the work. A proper question might be, "If

Now that you mention it, I got a "Label" notification on Tuesday from FedEx, but they still claim to have not received the unit. :-( (Tracking: 773378936874

Hello Jim Kits are going out in a day or so. Assembled radio orders are on a list and taking a while. I have almost 1,000 QMX boards, sets of components and enclosures in stock here at QRP Labs