Nicely presented Johan.

Just to note: I've been an EMC/EMI/RF engineer for over 40 Years, so I do understand what folks are saying. Thank you all for you thoughts and I'll let this drop now.

To further explain, my proposed usage is a roughly 5 Watt output from a SoftRock 40-30-20 (and a 17-15-10 version) using PSK31 as well as CW. I did some of the initial harmonic measurements for Tony 1

I'm going to be simplistic here: If I use the definition of "linear" being that, when I attenuate the amplifier output by its gain, the output waveform matches the input waveform very closely (without

Two thoughts: - terminate the input to avoid any RF coupling issues - be aware that heating of the IRF510s will cause huge bias variations. Make sure they are firmly coupled to the heat sink 73

I apparently fried my original 40 meter QCX yesterday. The reason was clear though. The ground pin of the +5 voltage regulator broke loose, allowing 13.5 volts through to everything on that rail. Here

I've built two of these now and have been able to get 10W or more out, but I have a question for the other builders: Can this be built as a "Linear" amplifier? As a career RF/EMC/EMI engineer, I'm pre

All very good thoughts, and I should mention that I also invested the relatively small amount of money it takes to have a few sizes and colors of magnet wire around long ago. Not a fan of using Sharpi

Availability currently depends on the STM32 version. F3s are very long lead. G4s seem to be pretty available. re-qualifying products for the change is a large part of my current work.

#qsx

30 gauge wire would come in two colors, to make keeping the primary and secondary windings visible. I do realize this is a cost hit for inventory and kitting, but it would be nice.

That would do it. The reason I've been thinking about doing this is software is to make the Si5351 itself the "switch".. I'm now thinking that the amplitude envelope is the bigger problem. The key sha

#si5351a #programming

Darn. I was hoping someone had played with the phase offset register settings. The thought was setting up two outputs 180 degree apart and switch between them for phase information. Having never progr

#si5351a #programming

I couldn't find it with a message search, but I expect someone here knows the answer to this question: Could PSK31 phase shift keying be implemented directly through the 5351 register programing, elim

#si5351a #programming

_Maybe_ related, but the HI adjust pot on my mini is a bit uneven in it's adjustment. Wiggling and external force doesn't cause a variation, but there is some "jumpiness" as you adjust, that is notice

#alignment #qcxmini

I had the same "problem" very recently. Thought for sure something was broken, only to discover that the only problem was my lack of patience! Ten turns end-to-end and three adjustments that heavily i

#qcx20mini

Since the 328 is socketed, a simple test is to remove it from the socket and _gently_ bend pin 17 (SIG OUT) just enough so it slides outside the socket when you re-insert the processor. You can then l

#troubleshooting

Somebody must have said this before. Connecting a 5V USB-TTL serial converter into the PTT interface (not hot plugged) also shorted the regulator with lots of associated failures. Horse is out of the

Hi Hans, If it ever comes time to update the mini's silkscreen for other reasons, I's like to suggest adding "CAT" and "PTT" to the edge of the display board.

Thanks to all! My apologies for spamming the list before doing more homework on the CAT protocol. 73

#firmware #problem #cat

I'm having the same problem here with a newly minted QCX-mini. COM obviously working to the extent of getting the ?; when I type any key (using Tera Term). Did you ever find the solution?

#firmware #problem #cat