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Re: QMX+ with ~1000 tone on 12M & 6M

 

Maybe a missing / broken / not connected C around the PCM1804? There are 10 capacitors.
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73 Ludwig
Re: PuTTY issue on Diagnostics screen

 

I forgot to mention that it only briefly worked when I updated the firmware.? At some point the problem returned and has remained ever since.
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Bill
W2EB
Re: PuTTY issue on Diagnostics screen

 

John,
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???? Is it also acting like my original post:? SMPS units seem to react in real-time, knobs and buttons slow but much faster than band change or "T"ransmit?? If so, we may have the exact same problem.? I gave up troubleshooting it as the rest of the rig works well so I don't need the diagnostics screen running.? If you'd like to compare rigs though, I'm happy to open it up and poke around.
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Bill
W2EB
Re: WSPR problem - U3S

 

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Hi Lucien
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Sounds to me like the "time of day" on the U3S is not being set / or/ not set accurat >>plus/minus two seconds<< ?WWV / ZULU?
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72 73
John
N3AAZ
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Re: Computer not connecting to newly built QDX

 

Found the problem! I was ready to send the thing to Jeff, W1NC to get his genius to work its magic to FIX this nightmare. He said he always does a close inspection with magnification before he sets about troubleshooting. So,? that is what was done here.
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Did anyone figure out why there is a smd LED on the bottom of that Rev 3a pcb? No matter, the search revealed I HAD NEGLECTED TO SOLDER THE FOUR ELECTRICAL CONNECTIONS TO THE USB RECEPTACLE !! I had been trying to load firmware into just a usb cable!
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Loading was a breeze! Got firmware loaded...first saw that Device Manager showed COM13 was recognised, got firmware loaded in a snap, connected to WSJT-X quickly and got a QSO with a W2xx call on FT8!
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Got into PuTTy easily and the rf sweeps are good on some bands and miss terribly on others. Might have to diddle with some toroids...
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But it works! Such a bonehead mistake! Gotta retrain every day!
--
73
Karl
KI4ZUQ
Re: These cursed little pwr supply boards...QMX

 

Hi Scott,
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as others have said, you can test the boards without the processor controlling them.?

I would find out which diode is missing and then replace it. I have three QMX, and two of them have diodes on the little boards replaced.?
--
Karl Heinz - K5KHK
Re: WSPR problem - U3S

 

Are you trying to send wspr or qrss?
Looks like qrss.
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.
WSPR problem - U3S

 

Nobody, including me can decode my WSPR signals on LF/MF and HF when I tx using 1) A U3S beacon and 2) A home made circuit based on an Arduino. Both transmitters used to get decoded OK. I have tested both in the shack and they seem OK to me. I can decode other people's WSPR signals just fine though on an IC-7300. My WSPR signal is decoded when using the IC-7300 as the transmitter on low power.
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The U3S gives about 313mW out on the 17m band. It draws 128mA not tx-ing and 250mA tx-ing.?
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My power supplies are a battery and linear types, I used a dummy load next to two receivers (dx394 and IC-7300) and pick up my weak signal but no decodes, and a loop antenna for outdoors, I use a GPS disciplined frequency source for the U3S and also a crystal control synth board, for the other I use crystal only. I use USB mode for Rx, no noticeable freq. drift using a GPSDO at 27MHz, GPS timing - spot on, recent Rx software.
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I can vary the Rx signal strength of my signals by repositioning the dummy load and get no decodes still be it weak or strong signals, I have set the Tx/Rx frequencies accurately and the Rx audio is in the centre of the expected range, I use a 100MHz bandwidth oscilloscope with an FFT feature to check the spectrum, at least for lower frequencies.
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I checked the look of the rx audio on Argo software the audio frequency deviation of 6Hz is correct. I use a nano VNA to check antenna impedance matching and get better that -10dB S11 which is OK. I have a low pass filter at the tx output for each band.?
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I went on air on several bands recently with my multi-turn loop antenna in the garden, it matches 50 Ohms well on nearly all the HF bands. I know the antenna works well with low power on 17m as the IC-7300 gets its WSPR tx decoded by others with 0% power setting.
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I have tried the U3S with a GPSDO and crystal types of 27MHz sources. The crystal one makes the U3S drift about 2-3Hz during transmission.
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These are the settings:
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3.12a 2017
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CW 10, Dit 006, Hel 000, speed -,?
Message - my callsign
Locator IO83CH
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Xw 0, X2 0, Tn 0, IV 0, TXS 8
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FSK 0, (fine Hz) 004
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Frame 04, Start 00
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GPS 1 (mode Baud) 009,600
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GPS 0 (Info, Check) 1
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Cal 02, (step, Time) 120
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Park 2, (Mode, Freq) 160,000,000
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PTT delay 000
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Shaping (ms 00, max 000)
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Sys Freq 20,000,000
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Ref Freq 27,003,288 (xtal synth)
27,000,001 (gpsdo synth)
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Bright 9, timeout 000
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Ftx 18,106,100
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The signal strength at the IC-7300 was S0, very weak but has additional lines at plus and minus N x 100Hz.
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There may be an additional issue related to this -?
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I have some power supplies, one a linear type (used in the tests above), one a switch mode type and the other is a car battery. I measured the AC (not DC) voltage across each and got 28.7V on the linear type, 29.1V on the filtered switch mode and 25.3V ac on the battery. Another DVM gave over 400Vac at times on the battery, fluctuating. Touching just the DVM lead gives 36mV ac. DC measurements are 11.9V battery, 13.6V switch mode supply and 13.3V linear supply. A scope probe on the linear one gives 62Vpp ac mains frequency, 50Hz UK (PSU on) and 7V ppk PSU off. Touching the scope probe tip gives 21Vpp ac. The mains ripple voltage superimposed itself on the measurement of power, above - Vrms measurement across the dummy load. Maybe the mains pick up affects the tx output spectrum, I listened on the IC-7300 and another receiver on AM mode and it doesn't have any buzzing sound though.
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I am puzzled as to why the signal is not decoded when using the U3S nor the home made circuit transmitters.
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Attachments - U3S-1/2 are screenshots of WSJT- and Argo for the GPSDO synth tests, U3S-c/d are of the xtal synth tests.
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Lucien
GW4SYI
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Re: Practice Mode

 

Dummy load is the simplest answer I've found.
--
72 de N4REE, Bob Easton - QRP CW forever
Re: QMX+ with ~1000 tone on 12M & 6M

 

I can hear the approx 1khz tone on all bands of my QMX+ v1.
Loudest on 12M and 6M, but to varying degree on all others.
Barely perceptible on 160M, but there.
It is not a 100% constant tone, there are small almost regular interruptions, as if digital and the breaks in the tone perhaps related to interrupt cycles(?). Beyond my knowledge base here…
Anyone else gone down the PCM1804 route as Jeff mentions and got a cure??
My radio appears to be working fine in all other respects.
I have built three QMX (mini) and not had any problems at all.
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Rowan.
G0KLH.
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Re: QMX+ with ~1000 tone on 12M & 6M

 

I think the 1408 is the issue.? I am going to order a small quantity to see if I can change
make that an 1804 ?
Re: Best QMX AGC settings?

 

Hello Chuck
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Initially I tried both lower and higher AGC thresholds, and
found they did not help the situation.? OFF seemed to do the
best at eliminating the noise modulation of the CW tones.

Did you try changing the other parameters other than AGC threshold??

I will look into it again when I have a chance; it has been a while since the AGC functionality was added and I get the impression generally most people think it is working well.?

I think that there are settings which could cause it to be scratchy.?

I do intend to create some "known good" settings to choose from to make it easy; leave the extensive full configurability in there for people who want it, but a few easy settings.?
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My SWAG on the problem is that the AGC routine's inputs
are from before the CW filters, and the AGC routines outputs
affect the audio levels after the CW filters.?

Something is causing the AGC to modulate the CW notes with
noise that otherwise isn't within the CW filters bandwidth.

How do I know this?? The noise is too sibilant and crackly
to have passed through a narrow CW filter.

The AGC action takes place AFTER the CW filter. If the crackling was generated by AGC that was ahead of the CW filter then the crackling would be filtered out by the CW filter...?
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I could not help but notice that many on this group speak
possessively about this product, as if they had something to
do with its creation.

I could not help but notice that many on this group beat their
chests threateningly and point out reasons why I should shut
my mouth.

Perhaps it is simply pride because you acted on one or more of
their suggestions?

Just enthusiasm, I suspect; most people here have had a lot of fun with the QRP Labs products. I am reading most of the posts here, I had not noticed people beating chests threateningly in regard to your questions.??
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I meant no disrespect.? My feeling was that if others are
speaking on your behalf, I should like to know so I can treat
their opinions as being more informed.

No problem :-)? ?Nobody speaks on my behalf.?

73 Hans G0UPL
Re: QMX+ 160m problems

 

Hi Dan,thanks for the suggestion, I will indeed try that next.
Hans diagnostic tools are great help with this sort of problem.
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While waiting for firmware to fix 160m problem is the bandpass filter response below typical ?
I will be doing Nicks suggestion around L401,C401.
73 Hugh GM8FXD
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Re: These cursed little pwr supply boards...QMX

 

There is a lot of useful information on this in the Wiki - see Left Menu.
I was able to test mine after my first QMX expired.
Rod
Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)

 

I confirm that nothing should be writing to the '5351 during receive. Even during transmit, nothing should be causing interruptions at 100Hz. Makes no sense... I would suspect the '5351 chip...?

73 Hans G0UPL



On Thu, Jan 9, 2025 at 8:05?AM Tony Scaminaci via <tonyscam=gmail.com@groups.io> wrote:
Adam,

I think Jerry is on to something here. If I recall, Hans runs the I2C programming at 1 MHZ so your 200 is gap sounds like 200 bits are being written at an unwanted time and the 5351 stops clock outputs until programming is complete and the internal PLL relocks. Just a thought…

Tony AC9QY

On Wed, Jan 8, 2025 at 7:13?PM Jerry Gaffke via <jgaffke=yahoo.com@groups.io> wrote:
Haven't had a chance to look at mine, but I'm quite sure CLK0 and CLK1 should have no interruptions when receiving.
Perhaps they are somehow shorted to another signal (but I still can't think of anything that's 100 Hz.).
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I believe that when receiving without turning the knob to tune different frequencies, the Si5351
should not be getting written to by the processor.? You might check the signals I2C_SCL and I2C_SDA
to see if the processor is writing to the Si5351.? And if it is, if it looks like it is occurring at 100 Hz.
Look at all of the other pins on the Si5351 too for something happening at 100 Hz.
If none of that leads anywhere, it might be time to try changing the Si5351.
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Jerry
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On Wed, Jan 8, 2025 at 04:41 PM, Adam wrote:
Turns out that CLK0 and CLK1 signals are interrupted for 200 microseconds at this rate (100 Hz).
Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)

 

Adam,

I think Jerry is on to something here. If I recall, Hans runs the I2C programming at 1 MHZ so your 200 is gap sounds like 200 bits are being written at an unwanted time and the 5351 stops clock outputs until programming is complete and the internal PLL relocks. Just a thought…

Tony AC9QY

On Wed, Jan 8, 2025 at 7:13?PM Jerry Gaffke via <jgaffke=yahoo.com@groups.io> wrote:
Haven't had a chance to look at mine, but I'm quite sure CLK0 and CLK1 should have no interruptions when receiving.
Perhaps they are somehow shorted to another signal (but I still can't think of anything that's 100 Hz.).
?
I believe that when receiving without turning the knob to tune different frequencies, the Si5351
should not be getting written to by the processor.? You might check the signals I2C_SCL and I2C_SDA
to see if the processor is writing to the Si5351.? And if it is, if it looks like it is occurring at 100 Hz.
Look at all of the other pins on the Si5351 too for something happening at 100 Hz.
If none of that leads anywhere, it might be time to try changing the Si5351.
?
Jerry
?
On Wed, Jan 8, 2025 at 04:41 PM, Adam wrote:
Turns out that CLK0 and CLK1 signals are interrupted for 200 microseconds at this rate (100 Hz).
Re: QMX Question for Troubleshooting

 

Don,
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I re-read your previous post and realized that you were working a problem where you did not have Vdd.? In that case I understand why the USB interface might not work.? Apologies for the confusion.
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Brien - KE7WB
New QMX+ build not powering up/accepting new firmware

 

Hello

I have recently built a Rev 2 QMX+, for 9V.

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I am attempting initial power up with a 9V battery to see if LCD turns on or if I can update the firmware.

I see neither the LCD screen go on, or see disk mounting actions to load the firmware.

I tried different computers and USB-C cables.

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I touched up all soldering points, and don’t see anything physical wrong with the board.

When I attempt power on (PWR/Vol knob) with a small amplified speaker connected I hear a loud click/thump.

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What would my first steps diagnosing potential issues be?

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Thank you.
Re: QMX+ 160m problems

 

I was able to go from 0.6 watts on 6 meters to 2.6 watts by removing turns from L520, the toroid closer to the antenna.? I ended up removing 4 turns, but you will want to do this one turn at a time, checking power out and the LPF curve as you go.
Re: audio volume QMX+

 

Charles
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Could it be your antenna is better on 40m?
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Could also be stronger signals then on 40m.?
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Try this. Find a spot on each band with no signals. See how the noise level varies across the bands.?
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Note the audio you hear is function of antenna behavior, it's matching and the qmx. Note when signals are present the AGC or lack of it can be very different than conventional receivers. Maybe all is actually okay. Signals were a bit strange today on the upper frequencies.?
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Curt
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