Re: QMX+ Power Supply boards problem
#qmx
Dear Dan,
I am in about the same position as you are... I did find a short under the GPS Module where the jumper for the VDD power was touching the
GPS antenna jack. I have been inspecting my board for shorts and opens but so far... Have not cleared the faults. If you can get it to load
the software .... You can use Putty to look and the hardware diagnostics. That will give you what the software sees. Mine says the 5V power supply is high and the 3.3V power supply is about 2.9V on the linear power supply. I can't seem to go any farther than that. I have changed the power supply boards twice. Not finding any bad solder joints and no other shorts. My board has an intermittent short on the VDD bus somewhere... But can't find it and all solder connections look good. Running 8Vdc on input voltage board draws about 200ma when turned on and nothing until I hold the power on button (Long press). Right now I don't know exactly what else to do. My 3.3V power board gets warm to the touch but so far no fire.
My front panel display has never lit up but I see the top row of digits are squares and nothing on the bottom row. Voltage to the readout but nothing but squares on it. Contrast doesn't seem to do anything but make them disappear. Woe is me. I may give up on this one and try again. My problem may be a board short.
Take care and have fun.
73 Dave WA5DJJ
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Re: QMX+ Power Supply boards problem
#qmx
Thanks Ludwig. I've started looking at it. Let me see what I can find out.
--
Dan Reynolds -- KB9JLO
<><
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Finally getting the qcx-mini broke in for summer camping season. One thing I have been noticing it the AGC has a remarkable pop on the first character sent from a strong station. With AGC off there is no problem other than having to ride the gain knob.
The adjustment on my AGC is very light. I set it up so that it has a very light action. This is because I sometimes share the audio out with a signalink. If I set it per Hans instruction, attenuation is too much to allow sharing of the signal out. So its barely adjusted above the minimum stop.
Any ideas appreciated.
--
regards,
Bryan, N0LUF
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Have a look here David,
I use a 6 band u3s running on 12v into a bank of 5v regulators, power out from 1w to 0.1w, can be heard worldwide, also lots of different modes available, also running a gps to set time and keep it on frequency.
Good bit of kit.
2200m: 0.137400 – 0.137600
600m: 0.475600 – 0.475800
160m: 1.838000 – 1.838200
80m: 3.570000 – 3.570200
60m: 5.288600 – 5.288800?
40m: 7.040000 – 7.040200
30m: 10.140100 – 10.140300
20m: 14.097000 – 14.097200
17m: 18.106000 – 18.106200
15m: 21.096000 – 21.096200
12m: 24.926000 – 24.926200
10m: 28.126000 – 28.126200
6m: 50.294400 – 50.294600
4m: 70.092400 – 70.092600
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.
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Re: QMX S9+ noise on receive
Bruce, Another way you might be suffering high noise while having acceptable sweeps is if there is a problem with IC401, the stereo DAC that drives the headphone amplifiers.
Finally, sitting between the PCM1804 and the CS4334 stereo DAC is the MCU. All the digital numbers that represent audio signals pass through the MCU, communicating in and out using the I2S serial data bus. It is possible, though less likely, that something is wrong along that path.
All of the above requires an oscilloscope at a minimum, and perhaps even a logic analyzer to resolve.
On this forum I have seen virtually no reports of CS4334 problems or of I2S data corruption. There have been some MCU failures, but usually they are not subtle ;-(
The PCM1804 has been something of a problem child in QMX and several of us are trying to suss out why that is. My bet is on the PCM.
JZ KJ4A?
Hi Bruce.? I'm listening to 15M CW right now and the band is full of CQ TEST. SKCC contest, I think.? So, AFAIK, my mid-band QMX is working just fine.? I've had QSOs on every band where my antenna is resonant...
John's assessment is probably spot on.? But a little noise on the ADC I/Q diagnostic doesn't seem to have impaired my QMX, for whatever reason.?
.rr
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Re: Hermes Lite 1 : RM Italy BLA 350 : QRP Labs 10W Linear
On Sat, Jul 13, 2024 at 08:45 AM, ajparent1/kb1gmx wrote:
a nice BLA-350 that with his 5W gives him 130W. It needs 10W for
full power (greater than 350W).
Again, the numbers do not add up. Unless the amplifier has a lot of gain expansion (compression is more likely) 10 W will only give 260W, far short of the desired 350-400W. I suspect that something like 15+ watts is going to be needed, likely more if the gain compresses. I also suspect that 400W is going to be elusive. If this were my project, I would beg-borrow a 100W transceiver and use it to characterize the amplifier over frequency and input power so that the OP knows what the actual situation is. Otherwise it is all just conjecture. 73, Don N2VGU
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Re: QMX S9+ noise on receive
Hi Bruce. I'm listening to 15M CW right now and the band is full of CQ TEST. SKCC contest, I think. So, AFAIK, my mid-band QMX is working just fine. I've had QSOs on every band where my antenna is resonant...
John's assessment is probably spot on. But a little noise on the ADC I/Q diagnostic doesn't seem to have impaired my QMX, for whatever reason.
.rr
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Hi John
I will email you off list....
73 Hans G0UPL
I need help to complete and pay for my qnx. KB7HNF
As soon as.I get a bill I will get with my bank and send.you a bank transfer.
On Fri, Jul 12, 2024, 10:57 AM Hans Summers via <hans.summers= [email protected]> wrote: Hi Chris
How do you mean, the "saturation of peaks"??
To me that sweep looks normal, healthy.
73 Hans G0UPL
Any thoughts on the saturation of peaks?
I am seeing similar plots on multiple QMXs.??
Firmware issue or Putty issue?
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Re: Hermes Lite 1 : RM Italy BLA 350 : QRP Labs 10W Linear
>>>Linear Tech's AD8009 highspec VIdeo amp is your friend here - costs about 5 Benjamins each from Chicom dealers . THese have been successfully used as driversfor RD 15HH Mosfets in class A to get 7 W linear out. Will give up to 24.7 dBM LINEAR power into a 50R single ended load at 12 V supply, without sweating the silicon. that's 7.7 dBm over your start position.<<<
Not useful at all for this application.
First he has 37dbm (5W) already from the HL2.? So there is no step up there as
24.7 DBM is 350mW and 7 W (using RD15) is still short of the 10W desired.
Plus a lot of construction to make it work.
Since he has 5W already its only +1.4db increase for that 7W.
So the QRPL amp with the HL2 17dBm output is a better match to the task.
If that ends up being too much drive a small low power (50mW) 2-4db
attenuation is far easier to do if needed.
--
Allison
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Post online only,?
direct email will go to a bit bucket.
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I need help to complete and pay for my qnx. KB7HNF
As soon as.I get a bill I will get with my bank and send.you a bank transfer.
On Fri, Jul 12, 2024, 10:57 AM Hans Summers via <hans.summers= [email protected]> wrote: Hi Chris
How do you mean, the "saturation of peaks"??
To me that sweep looks normal, healthy.
73 Hans G0UPL
Any thoughts on the saturation of peaks?
I am seeing similar plots on multiple QMXs.??
Firmware issue or Putty issue?
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Re: QMX S9+ noise on receive
Thank you Russ! I assume yor receive is working well? If so, what other areas could I check to see why I have such a high noise floor?
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Re: Hermes Lite 1 : RM Italy BLA 350 : QRP Labs 10W Linear
And here is another solution from EU1SW. Costly but offers 14-bit, 6m and 160m and power to run your amp to full output:
https://www.ebay.com/itm/256147932051
--
John AE5X
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Re: Hermes Lite 1 : RM Italy BLA 350 : QRP Labs 10W Linear
Timmy,
Your not paying attention.
Refresh yourself with /g/QRPLabs/message/125855
He has a nice BLA-350 that with his 5W gives him 130W. It needs 10W for
full power (greater than 350W).
So far you have given a bunch of suggestions that does not get him
that 10W and a few that can barely do what he already has. So stop
polluting the topic with wild and inapplicable ideas.
The best suggestion is the 17dbm output from the HL2. I'd try that first
as its fairly close to the ideal. It avoids the high power attenuation.
Still needs switching but Peter understands that.
--
Allison
------------------
Post online only,?
direct email will go to a bit bucket.
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Re: QMX S9+ noise on receive
I also have a fair amount of noise on the I/Q diagnostic. Also, the levels (35269) are different than what I've seen in the manual and posted here. But operationally, I have good sensitivity on all bands and I don't see any problem with opposite sideband suppression.
72 de Russ, va3rr
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Re: New feature request - Save messages etc.. on firmware update
Hi Sam
The messages are already retained in memory when the firmware is updated... In general firmware updates don't alrer the settings. They're only erased by a factory reset. Occasionally when I had to change the memory mapping, a firmware update automatically did a factory reset. But that won't in general be the case.
73 Hans G0UPL
On Sat, Jul 13, 2024, 13:30 Samantha Collins via <samcollins910= [email protected]> wrote: Hans,
I don't know if this is a possibility with the firmware / hardware configuration, but...
Is it possible that the messages programmed in are able to remain within the eprom when firmware is updated.
I use the messaging function of this radio (qmx) a lot (I'm a lazy cw operator hi hi) but always forget to re program them after doing an update and kick myself when out in the field. It's easy enough to use the terminal emulator to re do these when I get back to the pc but a pain in the butt when out in the field.
Just for clarity, I am disabled following a stroke and took to cw as speach was very difficult. But limb weakness means prolonged cw sessions can prove problematic hence using the messaging functions a lot.
Sam
2E1OCT
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Re: QCX mini with straight key
Joe,
I haven’t experienced this problem using a straight key. However, something similar occurs with a paddle and Iambic B with autospace turned on. Maybe autospace?
Steve
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Re: QMX S9+ noise on receive
Bruce,
The PCM1804 is likely bad.
That chip has been exhibiting a very wide range of failure symptoms in QMX, from subtle and noise related to complete meltdown. Yours appears to be a case of damage to the I channel but not so bad as to leave the device completely dead.
If you are not confident about your ability to change it, consider help from Jeff Moore W1NC, repair wizard and all-around good fellow.
JZ KJ4A?
So I am making a second post. I recently assembled a QMX. Fired up at 7v limited to 200ma. Loaded the firmware. The transmit on all band is great with 4 to 5w. This is a 60 to 15m model.
The problem I have is it is mostly deaf. Only if a station is like S9+20 will it exceed the noise level and be able to be heard.
I am posting various sweeps here. First the swr sweep for 40m looks good to me.
Then the RF 40m sweep looks good to me also.
Then the 40m lpf sweep, again I see no issues.
Now the image sweep. This compares favorably to the manual so I believe this is good as well.
Now the AF image sweep. This is similar to the manual, but my lsb is only down -40 and not -60 like the manual shows. I am not sure what would cause this.
Lastly the ADC sweep that Hans just created. I see the I and Q 90 degrees out of phase so I believe that proves my tri filar torroid is fine. The sweep however is not clean like the example. There is significant noise, at least it appears that way to me.
Please if anyone can help. I have my suspicions it is the PCM1804, but I am not an engineer.
Thanks everyone.
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If I understand you correctly, you're looking for the WSPR freqs for each band. Page 35 of the QMX operating manual lists them--or did you already know that? In any event I usually aim for a frequency somewhere between the extremes. For example on 20m I usually use something like 14.097.140. Beacon mode works perfectly provided all the parameters are set up right. Hope this helps. Mitch NK3H
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Re: Another QMX+ got onto the air
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Thanks Hans, for adding the links :-)
Small update on my QMX+.
Like all the cases from QRP-Labs, I really love the QCX+ / QMX+ case. But when you the have QCX+ or QMX+ case it on a desk, the ergonomics aren't that good. Just try to turn the tuning dial and you feel what I mean.?
But luckily I already solved this problem with my and with my experience on the I desiged to re-design the original QCX+ tilling feet so, the they could be used with strong double sided tape.
I used this tape from or if the link is broken, google for "hxres tape".
 ?
I have very good experience with this tape, it's strong like hell, but this is the first time I tried it for the tilt feed on a case of this size (used it also for the QMX-mini but that case is smaller). So success is defiantly not guaranteed.
The height of the 3D printed tilt-feed is the same as the rubber feet supplied with the QMX+ case. So no wobbling whats so ever.?
 ??
Now the ergonomics is much better when using the QMX+ on the desk. For now I leave it stand on the work bench for a day and if tomorrow morning the case is still in this position, the tape is approved for this job :-)
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73 Lex PH2LB?
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Thanks Karl. You are running the QMX via wjst ?
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Dan Reynolds
M0RON
Donald S Brant Jr
va3rr
David Perry