Re: #qmx video: 52 tips for building your QMX successfully
#qmx
Hello Hans,
Thank you for the excellent Video. I think I can use it for the building of the QMX, which arrived me yesterday without any problems.
Vy 73 de Dc4kjs?
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Re: is there anyone who would be willing to replace the si5153a synthesizer chip on my qcx?
Hi Rick,
There must be someone nearby who can help you out, just in case you want to try yourselves with a regular soldering iron: here is how I do it:
1. add excessive solder on both sides of the IC, then by quickly alternating the iron tip from one blob to the other you can keep them both melted, when that happens you can shift the part away from the footprint, and it is removed.
2. cleanup the solder tip with a wet sponge, and heat the solder that is left over on the footprint, repeat; heat only quickly and without force so that the footprint will not get damaged.
3. place the new IC on the footprint with the dot on pin 1 and pins centered on the pads, press the IC to the PCB when aligned and heat the pins, do not add any additional solder as this will create bridges. make a photo with your phone, zoom-in and inspect.
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That's exactly how I wound mine, Nick.
Its also exactly as per the picture of the Stockton bridge in the NorCal power meter PDF linked earlier in this thread, so I think you are good to go.
73 Jon
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Re: Power supply for pre-assembled QMX
Hello Sholto
I made a note on your order? 73 Hans G0UPL
I have the same question Hans. Is it possible for invoice 72091 to be made for 9V?
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Re: IS THERE ANYONE WHO WOULD BE WILLING TO REPLACE THE Si5351A SYNTHESIZER CHIP ON MY QCX?
If you have a soldering iron then you do have the equipment. Use a bevel or chisel tip.
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Perhaps it's easier if I post a picture? Can anyone tell whether this is correct?
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Re: No Sound Card digital modes
Hi All
The use of audio as the universal way of transferring digital Signal modes between a PC and a radio transceiver makes lots of sense in many ways. Every radio transceiver for more than a century has an audio output and if it's a phone transceiver, an audio input. So the digimodes software writer knows that his software will be automatically compatible with every radio in excistence.?
The moment a Digi mode software starts producing custom ways of sending out digital symbol information, it's no longer compatible with anything. And every radio model then has to update it's capability (if it even is possible) to handle these messages.?
So it's not really a logical direction.?
The way QDX and QMX are designed with the built in USB sound card emulation, the transfer of audio between PC and transceiver is lossless, distortion free, hum free, etc. It's quite straightforward and fast, and incredibly accurate, measuring the audio frequency and applying it at RF. So the system as it stands, doesn't cause any problems and wouldn't be improved by any other method.
On Sat, Aug 26, 2023, 1:24 PM Vojislav [YU4HAK] < batica@...> wrote: Wsjtx does however at least show what is being sent and received in two places other than the screen. In the UDP data stream, and logged in the all.txt file.
What I managed to do for my experiment is to track the all.txt file with a small node.js app, encode that message to ft8 frequency offsets and send that number via serial port to the Arduino that controls the si5351.
It is clumsy but it kinda works. And no visible latency either.?
While this is far from finished and useful, it is an idea how annoying "audio coupling" between wsjtx and a transceiver that does direct signal generation can be done with a small software shim.
In theory, it wouldn't be too hard to add optional "current message output" to existing wsjtx cat serial data, but haven't explored that yet.?
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hello Nik, if they can help you but I'll give you some photos of my QMX, I'm waiting for the replacement power supply board because I got Q103 trying to unsolder it.? 73 and have a nice day Giuseppe iu8eun
It would be useful if the next documentation update would show a clear and totally unambiguous photograph (or two) to show how this entire T507 assembly ought to look when mounted in the QMX PCB. Until then if anybody is able to post any such I photographs then I suspect several builders might appreciate it.There is a? photo in the 1_00h assembly manual but it doesn't clearly show whether the thin wire in to the core hole at the left of the picture then comes back at the 'top' or the 'bottom'.
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It would be useful if the next documentation update would show a clear and totally unambiguous photograph (or two) to show how this entire T507 assembly ought to look when mounted in the QMX PCB. Until then if anybody is able to post any such I photographs then I suspect several builders might appreciate it.There is a? photo in the 1_00h assembly manual but it doesn't clearly show whether the thin wire in to the core hole at the left of the picture then comes back at the 'top' or the 'bottom'.
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Re: QDX - Stuck in transmit mode when using VOX even after disconnecting PC.
On 27/08/2023 05:53, jlloydham wrote: One or two times per operating session my recently assembled Rev 4 QDX fails to return to receive mode after a transmission completes. This reminds me of reports caused by RF (getting in the USB cable?), the QDX locks up. Is it a borderline case? 73 Alan G4ZFQ
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Re: #qmx video: 52 tips for building your QMX successfully
#qmx
I agree about pushing the power
connection to the board edge. I did that and there's enough
clearance not to need adding insulation.
Otherwise what I did was to wind the
toroids first and do a dry assembly of everything in the LPF area
to make sure that everything fitted.
Then solder everything more or less
from the outside in, finishing with the toroids.
A few other thoughts:-
When fitting the connectors between the
boards I fit the boards together with the connectors then solder a
couple of pins on each connector while fitted together so they jig
each other.
I squeezed the pins for the PSU boards
together slightly so they touched the board.
When soldering the BNC fit the display
and main boards together in the top of the case with the BNC
attached to the end plate and the plate fitted to the top half of
the case. Maybe the other end plate also fitted.? This holds the
BNC and main board in the correct orientation while you solder it.
Chris, G5CTH
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Hans, I can add one tips:
When installing the input power connector, push it towards the
board edge.
This will increase the very small clearance to the left encoder on
the control board.
Nevertheless I put kapton tape on the encoder body facing the
power connector
73 de SM5EIE /Gunnar
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QDX - Stuck in transmit mode when using VOX even after disconnecting PC.
One or two times per operating session my recently assembled Rev 4 QDX fails to return to receive mode after a transmission completes. I'm using VOX and currently don't have a good way to use CAT to toggle between TX/RX. The LED repeats the two flashes indicating low audio level from the PC. However, no audio is being sent to the QDX at all so it should return to receive mode. Things I have checked/tried while the 2 flashes are happening:
- Both lowering the volume on the PC and muting it - No effect, flashes continue
- Unplugging the QDX's USB cable from the PC - No effect, flashes continue
- Checking Input Analysis shows NO SIGNAL
- Transmitting from the Transmitter Test menu in the QDX terminal (No changes to PC) - Flips it back to receive/normal function.
- Power cycling the QDX - Returns to normal operation
As this doesn't stop even when the USB cable is removed I don't think there's anything on the PC causing it. The QDX otherwise works great. It has happened both when transmitting into my antennas and on my test bench into a dummy load so I don't think it is an RF problem. My best guess would be a firmware bug but I don't see any mention of others seeing this issue. Maybe not a lot of VOX users? QDX Rev 4 with 1_10 firmware. I would be open to it being an assembly issue but I can't think of anything that would make the QDX think a stream of bits are being sent to it when the USB cable isn't even connected. If anyone has an idea of something I should check let me know.?
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IS THERE ANYONE WHO WOULD BE WILLING TO REPLACE THE Si5351A SYNTHESIZER CHIP ON MY QCX?
Hello, All—
Is there anyone who knows how and would be willing to replace the Si5351 synthesizer chip in my QCX transceiver with a good one? I do not have the equipment or equipment to do the SMD removal and soldering.
I will gladly pay for your time and expertise.
THANKS!
Rick, W B 3 B I Q
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Re: #QMX 3.3V Supply won't come up -- HELP!
#qmx
I tried powering the 3.3V line direct from my test power supply
with a 250mA limit. Went into current limit immediately. Guess the
CPU is slagged. :-(
Still don't know what I did, either!
Sad Paul.
On 8/26/23 15:50, Paul - AI7JR via
groups.io wrote:
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LIN_REG_EN doesn't start at 12 V, it's staying at 0.7 volts, so
the 3.3 V rail never gets power and the uP never starts. Pull up
is working, no short to ground, on this line.
See?/g/QRPLabs/message/108481,?for
the whole story.
Am I SOL?
Paul -- AI7JR
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Re: #QMX Tweeking QMX output power
#qmx
On 25 Aug 2023 at 12:49, Stephan Ahonen KE0WVA wrote: I intend to run off a car battery
inverter so I took some extra steps to
ensure thermal performance at 13.8
vs. 12. I put thermal paste between
the bss170s and the ground plane,
and a thermal pad on top to try and
conduct more heat into the washer
holding them down. Maybe at some point
ill replace the washer with an
aluminum bracket that attaches to the
inside of the enclosure to conduct
the heat out that way. why don't you just use one of the several BUCK converters that have been suggested on here over and over? That would GUARANTEE 12.0vdc into the rig no matter what your auto generator / regulator puts out (I've seen my car go up to over 14v while running). w2jc
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Re: QMX 9 volt current consumption and a 9 v upconverter?
Mine varies slightly from band to band but the highest I've seen on TX is about 1.3A from a lab supply set at 9V.
Jonathan KN6LFB
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Re: QMX 9 volt current consumption and a 9 v upconverter?
Hi Rich,
I recently completed a QMX and have a USB powerbank so I thought I would give it a try.? The USB powerbank? I have is a PD type rated at 10,000 mAh 18W.? I have a PD "dongle" connected to it so that I can select an output of 9 or 12Volts.
So, with the dongle set to 9V, I measured 9.14V output.
Running the QMX from this, I got the following transmit outputs.
80m 3.0Watts
40m 3.25Watts
30m 4.0Watts
20m 3.5Watts
Current draw was between 0.8 Amp and 1.2 Amp.? The PD powerbank is rated at 9V 2 Amp output.
So it ran the QMX comfortably and a quick receive check didn't show any significant interference from the powerbank or dongle.
Cheers,?
Glenn VK3YY.
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QMX 9 volt current consumption and a 9 v upconverter?
While I await delivery of my factory-built QMX (~110 on the wait list) I am wondering what the max current consumption might be? I've got a 10,000 mAh? 5 volt USB "brick", and I'm considering using a 9 volt upconverter to power the rig.
Thoughts?
Rich, KY6O
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Re: Anybody running 6m on QDX?
Jerry,
you should be able to setup 6 meters in the band configuration screen.?
73
Evan
AC9TU
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#QMX 3.3V Supply won't come up -- HELP!
#qmx
LIN_REG_EN doesn't start at 12 V, it's staying at 0.7 volts, so the 3.3 V rail never gets power and the uP never starts. Pull up is working, no short to ground, on this line. See? /g/QRPLabs/message/108481,?for the whole story. Am I SOL? Paul -- AI7JR
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Stefan
Rick Nelson
Paul - AI7JR
Glenn S