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I think I can manage it being that you pointed out where these three traces go. I was a little overwhelmed until you explained what was going on. I’ll know more later this evening.?

Curt
WU3U

Hi Hans, keep me on the list for a new board for now but I will look closer at the board later tonight under the magnifier to see what you are suggesting. I don’t think cleaning up the remaining ground pads and tacking the chip back down to them will be a big deal. I guess at first look my concern was the traces going away from the resistors which must be more of a test point pad than anything. I thought maybe they were connected somewhere else which would have really messed things up. Looking at another picture that I took it looks like pins 6 & 8 get connected to the opposite sides of R21 and pin 5 goes to R20. I’ll give it a shot this evening and report back. Maybe I can do it with some Cat 5 wire if I can’t find any #28 magnet or insulated wire around.

Curt
WU3U

Quick question, has anyone tried a quick "Tune" command in WSJT-X to see if that resets the CAT link?? From the limited information that I read here, it sounds like a "critical path" problem that I ran into MANY times in industrial control systems where the reset signal was dropped in the exchange.

Just curiosity on my part.
73
Evan
AC9TU

Well - I use a new M1 iMac , but I do not have any problems using any of my other radios from the same iMac -
Same cables etc - so I do not think its a PC issue

73 - Knut??

That sounds like a Windows issue. I still have to change the audio setting on my taskbar every time i change from WSJT-X to listen to a video.?

I also see some strange behavior sometimes - only way to get it work again - is to go to the audio setting on the wsjt-x - do not need to do anything - just press ok - and it works again.

Sometimes it stops totally - then I go to the radio tab - and pressing Test CAT - all works again.

Tested using different USB cables etc etc but no differences.?

And I do not have this problem when using my Icom radio - and there is no RFI in my shack - and a good and stable 12V supply.?

But - the radio works great - except for this??

?

73 - Knut?

?

Hi guys, I received my QDX early last week. It was under order number 50038. ?When I opened the package I noticed that IC6 was lying loose in the box with some of the traces completely removed from the board and in my opinion unrepairable. I immediately submitted a ticket on their website and a few days later emailed Hans at an address that I had for him but have not received a response.?

I see that Hans is answering some information on here so I thought I’d make a third attempt at contacting him to try and get my board replaced.?

Please help!

Curt
WU3U

"In the

simplest case, the QCX is operated without any modification on bands below the cutoff frequency

of the TX lowpass filter"?

Julian,

Good advice on the winding.? I would add just one point, get two different collar #28 AWG enameled wire, and use that to help in the identification of the coils.? You can use that wire for any future bi or trifilar transformers in future projects.

73
Evan
AC9TU

You just saved me so much time, thank you!! I'm also experiencing this, only on 20m.? It happens all the time for me so I thought I hadn't soldered C29 or L12 correctly.? I was about to start troubleshooting the circuit but it sounds like a firmware issue.

By the way, I'm so happy with this thing.? Today was my first time on FT8 and I'm hooked.? Made contacts in 3 countries in the matter of minutes.??

73
Dennis AB1NX

On Thu, Nov 4, 2021 at 09:28 AM, Julian N4JO wrote:

Essentially I solder in the three connections on the right side, then unwind the three connections on the left, ring them out to identify, then feed through and solder.

So to elaborate on that, and on winding the trifilar transformer in the first place, this is what I did, expressed as instructions...

Stage one.
* First, cut one length, three times as long as recommended plus maybe an inch, and fold it twice loosely to make a single assembly of the intended length. (From past experience winding tri-filar transformers I have learned that keeping the two folds (one at each end) helps keep the assembly together.)
* Pull that assembly out straight so that the tension is equal in all three strands, as parallel and straight as possible, tightening the two folds to complete the job.
* Drive a nail or a screw into a stud in the middle of your living room wall, half way up...
* No, on second thoughts, don't do that. Find a place, anywhere, in the garage, for example, where you can put a nail or a screw in the wall, and do it, leaving half an inch protruding, just above or just below eye level. Don't ask me why...
* Attach the wire assembly to the nail by looping it around, then twisting the end half inch back around the long length for a couple of turns.
* Attach a small screwdriver to the free end in the same manner.
* Pulling gently downward, twist the screwdriver like a corkscrew, two or three turns at a time. The twists will tend to aggregate at the screwdriver end, so... gripping the wire assembly between your first finger and thumbnail, attempt to coax the twists up toward the nail end. It will work well enough, though it will wreck you thumbnail, sorry. If your XYL has longer thumbnails than you, you could ask her to sacrifice one for the cause... then again, maybe not.
* Continue twisting, two turns at a time and dragging the twists up toward the nail end of the assembly. I found that fifty turns was quite tight enough, as I was careful to coax enough turns up the length of the assembly to leave it sufficiently twisted all the way along.
* Unwind, don't cut, the assembly free from the nail and the screwdriver. Leaving the turns at each end helps to keep the assembly intact as your wind the toroid. Leave the nail in place: you're going to need it for the QSX or something one day, aren't you? ;-)
Stage two.
* Wind the toroid - 10 turns - in the direction specified in Hans' notes. Let the screwdriver end be the long end as you wind - the end you push through the toroid: the tighter turns at that end will keep the assembly together. Coax the wires through the center of the toroid, forming the loops with your fingers as close as practical around the outer edge of the toroid on each turn. Do NOT allow the wire to scrape against the sharp inner edge of the toroid as you pull it through; the stiffness of the wire assembly and the sharpness of the edge are enough to remove insulation from the wire, and you do NOT want to do that...
Stage three.
* Unwind the three wires on ONE side of the toroid (cutting off the loop on that side) up until the point they go through the center of the toroid as one.
?* Feed the three wires through the set of three holes on the inside of the board, nearest the capacitors, snug them down, and solder them.? Don't trim off the ends yet...
* Instead, bare the ends of the wires using a soldering iron and solder.
* Check continuity between each of the three bare ends against its respective soldered joints, to make sure your soldered joint is complete. You can use this continuity check trick for other toroids. Don't trim the wire ends just yet; instead lay them flat, making sure they don't touch each other.
* Now unravel the three wires on the outer side of the toroid - cutting off the loop on that side - up to the point where the assembly goes through the center of the toroid.
* Bare each wire end using the soldering iron and solder (don't trim the wires to length just yet), and continuity-check each end with its corresponding pad on the other side of the toroid. As you have already performed an integrity check on the connections on the inner side, you can "beep" to the pads on the top side of the board.
* Now feed each wires through its respective hole, straightening the kinks in the wire as necessary.
* Perform that continuity check AGAIN. It is very easy, as you're fiddling with feeding those wrinkled wires, to accidentally swap two of them.
* Finally, solder the last three wires.
* Perform the continuity check on the three ends on the outer group with their corresponding pads.
* One last step before trimming: reheat each of the six connections, gently pulling any remaining slack though the holes. Re-do the continuity checks for any wires that brought the bared section of the wire out and away from the pad as you pulled it through.
*? Now trim all six wires close to the board, making absolutely sure not to damage the surface mount components near?the inner group ! Note that now all the coils are soldered to the board, a continuity check will show that two of the coils are now connected in series, and one coil will be isolated.

That's how I did it. I am happy with the result, and will do it that way next time.

Other notes:
Make sure you lay the power, USB and BNC connectors flat against the board and at right angles to the edge as you solder them, or they won't align properly with the holes in the end panel. Solder one connection near the edge, check the positioning, then solder the rest. I'm of the opinion that it is better to solder the retaining pegs of the BNC socket first, then the electrical connections, because that order minimizes stress on the pads of the electrical connections.
If you can remember to not solder the positive terminal of the power socket and the in-board terminal of the USB connector, you can feed the leads of the power supply capacitor through those holes to solder them..

--
Julian, N4JO.

You bet! Shoot me an email and we'll figure something out ?
--
Ryan Flowers - W7RLF

Ryan - you up for a sked?
--
John AE5X

My 22g wire arrived today, T1 is rewound and installed. I tested the little riglet on all 4 - no, 5 - bands and had QSO's on all of them. What a great radio - lot's of fun!

Here are some numbers you may be interested in:
On all bands, DC in is 12.0 volts, T1 is wound with a 3:2 ratio.

BAND - RF OUT - Current draw
20m - 3.5 watts out - 530mA
30m - 4.0 watts out - 550mA
40m - 4.25 watts out - 560mA
60m - 5.5 watts out - 690mA
80m - 5.0 watts out - 670mA

I haven't tried to adjust the windings yet on the LP filter inductors for more RF out.

73,
--
John AE5X

It depends on the item with the largest thermal mass. For a grounded pad that's definitely the best way to go, but for a half mmm copper wire you'll be there all week and liberate the pad. In any case, allowing a small amount of solder onto the tip of the iron improves heat flow, and it also release some flux, which is what cleans the joint and allows bonding. But yes, the solder should certainly be removed before the iron!
--
Julian, N4JO.

Not even slightly.? The filters are resonant, meaning that they both reduce harmonics and boost the fundamental. You could consider that the filters take the energy off the edges off the square wave and add it to the center of the waveform to boost the middle to make a sinewave of greater peak amplitude than the original square wave. There's no way you'll get thirty-odd volts peak to peak from a 12 volt supply without a resonant filter circuit, and I don't even want to think about the splatter of harmonics all the way up to daylight that you'll be emitting. If you want to measure the initial drive to the LPFs, you could measure the waveform at the drains of the output transistors, but leave the LPF in circuit if you're connecting anything to the output, even a dummy load.

--
Julian, N4JO.