Here are my output values by band. I did a little squeezing and expanding with the Low Pass Filters but didn't gain much. I'm not sure if these are typical or not.
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BAND??? Output Watts
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160???????? 4.8
?80????????? 4.2
?60????????? 3.4
?40????????? 3.6
?30? ? ? ? ? 4.1
?20? ? ? ? ? 3.1
?17? ? ? ? ? 3.2
?15????????? 3.8
?12? ? ? ? ? 3.5
?10? ? ? ? ? 2.5
?? 6? ? ? ? ? 2.3
--
73, Rick
VE7TK
Website:
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Re: QDX: Troubleshooting high output power
Ok, I found that L4/L10 weren't soldered well.? Now I think I'm getting closer to right thing regarding the diodes, but still not sure they are quite right.
Running 9V, I am getting 7.2V across the diodes of the "off" bands and 0.67v across the diodes on the "on" bands.? However, the RF sweeps are still way off and it is still just transmitting for less than a second if that.
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Hi All. Back in 2020 I mistakenly ordered a Si5351 that was pre-programmed for a fixed frequency and it did not work in a QCX I was repairing. I had to order the correct one that was not programmed. Since then I've only used the un-programmed versions, both Si and MS5351 depending on what was available.
Ron
Far as I know, the MS5351M has no documentation for its internal registers.
The only documentation for those registers is what was written by SiLabs for the Si5351.??
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The MS5351M is not available from US distributors, you have to get them from China.
(EBay doesn't count.)
?
I defer to Hans on the question of whether a factory programmed variant of the Si5351?
is suitable for use in his products.?
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Jerry, KE7eR
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?
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On Sun, Oct 13, 2024 at 01:23 PM, Bruce Akhurst wrote:
So as the original ones or the MS version are currently widely available and will likely be purchased and changed to trouble-shoot (not further confuse the issue) why would you even bother wondering
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Re: QMX article in the QST
Thanks - colors did not reproduce correctly in the specs on the left side of P38. Here's a version with correct colors.
-Steve K1RF
------ Original Message ------
Date 10/13/2024 5:53:04 PM
Subject Re: [QRPLabs] QMX article in the QST
Here's a fair use copy of the review only:
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Re: Why not provide a MP3 of an actual MCX+?
Hi Chuck,
I think I have the same feelings as you when it comes to CW. ?I had two Yaesus, with cw filters- different machines, and I just could not have a pleasant experience with either of them on CW.
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I went to a couple of older Elecrafts and had an ¡°aha¡± moment. ?Easy to listen to the code, and I was not fatigued after a few minutes.
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I have a QMX+ running v.27 as well now.
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All I can say is Wow! ?How did Hans do this? ?I A-B¡¯d the K2 with the Qmx+. ? The QMX+ is punching way above its weight on receive!
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73,
de Chris W3PB
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Matthew,
My 12 volt QMX draws plus or minus 200 mA at first, then drops to 95 mA once the switching power supplies are working.
Is your current limit set high enough to allow the initial inrush current? I had my power supply set too low at first, around 140 mA,
and the voltage would drop dramatically as the current compliance kicked in. I thought there was a big short at first.
Since the radio wasn't actually running there was no USB connection, either.
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For transmit I need to have the supply current set to 1.1 A or a bit higher.
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Best of luck,
David N6AN
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Re: QMX article in the QST
Here's a fair use copy of the review only:
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Re: Why not provide a MP3 of an actual MCX+?
Interesting that you call IC7300 as "WARM" when many like to?
complain about the hiss.? I have one and it has with the
gain up a lot of HISS compared to my TT Triton.
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Myself I find the Q(C/D/M)X kits audio very good to my ears
when below overload levels.? When at overload levels they
are like many to my beat old ears.. distorted.? Not their fault
just my lack of applying the volume control.
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--
Allison
------------------
Post online only,?
direct email will go to a bit bucket.
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Far as I know, the MS5351M has no documentation for its internal registers.
The only documentation for those registers is what was written by SiLabs for the Si5351.??
?
The MS5351M is not available from US distributors, you have to get them from China.
(EBay doesn't count.)
?
I defer to Hans on the question of whether a factory programmed variant of the Si5351?
is suitable for use in his products.?
?
Jerry, KE7eR
?
?
?
On Sun, Oct 13, 2024 at 01:23 PM, Bruce Akhurst wrote:
So as the original ones or the MS version are currently widely available and will likely be purchased and changed to trouble-shoot (not further confuse the issue) why would you even bother wondering
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Why not provide a MP3 of an actual MCX+?
What a great persuasive writeup on the QRP Labs site for the QMX+.?
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Since Audacity graphical output is used in the presentation,
why not attach the actual MP3 file?
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With my present degraded hearing I find CW audio output from
the QCX et al kits unpleasant and very hissy. Not warm at all
compared to (say) a 7300 or 710. I am reluctant to buy further kits.
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Would it be possible to prepare a preview listening experience?
?
Chuck w8mqw
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Something is pulling down on the 3.3V supply so the power-up sequence cannot complete.? That is why IC101 is getting hot - its output is shorted (or nearly shorted) to ground by something.? Or maybe it was defective in the first place, but that's not very likely.
Note that the general power-on process is this:
1 - pressing the power-on button turns on Q103/Q105, which puts the voltage from the input jack on the +12V rail
2 - this +12V goes to the input of IC101 which creates the initial 3.3V VDD voltage via D103, which is also connected at the top of D109.
3 - this VDD voltage powers on the CPU, which then sets up the switching power supplies, and turns on VCC via Q108 and switched VDD via Q111.? The CPU then turns OFF the IC101 3.3V (i.e. changing from the linear 3.3V supply to the switched one).? This all happens in about 1/4 second if all is working well.
So when you press the button and only 12V comes on, usually it means the initial linear 3.3V supply (IC101) isn't getting voltage to VDD to power up the processor.?
This can happen for multiple reasons.? If you can measure 3.3V at the output of IC101, but not at VDD, it often means that D109 (the protection zener diode) is blown and shorting the VDD pin to ground.? It could also be soldering issues, connector issues, or other components further downstream.
So the first trouble-shooting step is to check D109, and everything on the 3.3V power supply board.
And if you haven't already done so, look at the Wiki on this group, it has lots of pertinent info:
And this video is worth a review, it has lots of common issues to look out for:
Good luck.
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Jerry
As the kits have never been designed/tested? for anything but the standard Si /MS 5351's they were sold with - and the earlier models were pretty tight for code space to cover other options)
- And I have never (even during the great 5351 shortage) seen it said that any 5351 version with any factory programming will work in any radio.? ? (Maybe I missed it but? . . . . )
So as the original ones or the MS version are currently widely available and will likely be purchased and changed to trouble-shoot (not further confuse the issue) why would you even bother wondering
But if someone with a working radio has time and wants to try it on all modes/bands/conditions and report back maybe its fine.? I just don't see any reason to add another variable to a tricky repair if its avoidable.??
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I have just built a QMX, but it doesn't power on and appear as a USB device.
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I have built it for 9V, and have applied a voltage of 8V from a current limited supply. Prior to depressing the left encoder, current draw is 0A. On pressing and holding the encode, current goes up to 0.3A (or even 0.47A if I increase the current limit) but immediately drops to 0A on releasing the encoder.
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If I hold down the encode, current draw remains at a few few hundred mA, and IC101 on one of the power supply boards gets hot to the touch.
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The board has been very thoroughly checked visually and using a DMM prior to first power on. All the connections on the power board are fine,?
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Any suggestions on how to troubleshoot would be hugely appreciated.
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Many thanks
?
Matthew
M0MZB?
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> 1) For some reason, PuTTY refused to work on my Win10 desktop (it had worked in the past). It recognized the QMX on a serial port but then it just "hung". Luckily, my > Win11 laptop worked perfectly and I moved on to the diagnostics.
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Found no issues with the terminal and just debugged a QMX+
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> 2) Power out ranged from a high of 5.0 watts on 160 to 2.3W on 6 metres. (This is quite acceptable for sure.)
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Beyond 15 meter I'm losing power, at 6 meter it is less than 1 watt, so I will check the filters again.
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73 PA1EJO Ernst
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Re: QDX: Troubleshooting high output power
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And started measuring the voltage on the diodes in different bands.
When I'm on 20M, D1/D2/D4/D5 are "high" (8.06V to ground when the board is running at 9V)
However, D3/D6 are at 4.7V when, according to the above post, it should be close to zero.
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Measuring the X6 test point, only "2" is at 3.3V (the other two are at 1.8mV).
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What should the voltage at D3/D6 be at this point?
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Many thanks Alan!!
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After all those toroids I REALLY needed more practice with 44 turns of #28 wire on a T50-2 core! Hi!!
--
73, Rick
VE7TK
Website:
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On 13/10/2024 18:57, Rick Williams - VE7TK via groups.io wrote: 3) The biggest problem was the image rejection on 160M. No problem! This is waiting for a firmware update. 73 Alan G4ZFQ
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Salut Nicholas
Merci pout ton cover pour le QMX.
J'ai essay¨¦ d'allonger le couvercle avec des languettes de verrouillage aux extr¨¦mit¨¦s, car le QMX glisse facilement lorsqu'il est utilis¨¦ comme support.
Mais je n'ai pas r¨¦ussi ¨¤ le faire dans Fusion360.
Pourriez-vous peut-¨ºtre mettre ¨¤ jour le fichier avec des languettes de 2 mm aux bouts, afin que le QMX ne glisse pas laterallement ?
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Cordiallement?
OZ1MIC, MIchael
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I have just finished building a Rev 2 QMX+. It was a fun build and all went smoothly ... with a couple of minor exceptions.
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1) For some reason, PuTTY refused to work on my Win10 desktop (it had worked in the past). It recognized the QMX on a serial port but then it just "hung". Luckily, my Win11 laptop worked perfectly and I moved on to the diagnostics.
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2) Power out ranged from a high of 5.0 watts on 160 to 2.3W on 6 metres. (This is quite acceptable for sure.)
?
3) The biggest problem was the image rejection on 160M. Here's a table of the results:
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Band????? Image
160????????? -3.8 (no the decimal point is correct!)
? 80????????? -37
? 60????????? -41
? 40????????? -43
? 30????????? -46
? 20????????? -50
? 17????????? -58
? 15????????? -36
? 12????????? -35
? 10 ? ?????? -38
??? 6????????? -20
?
In an effort to resolve the 160M image problem I removed L401 and rewound it! Unfortunately nothing changed. I also went into the band configuration and changed the BPF from 0 to 1 just to see what happened. Nothing changed? So it looks like BPF 0 is not there for some reason?
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The chances of me using this rig on 160 with 2.3W are fairly remote, however, it would be nice to get the image numbers to a more reasonable level.
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Thoughts appreciated. Thanks!
--
73, Rick
VE7TK
Website:
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Re: Clear SWR Protection "S" through the USB port?
FANTASTIC!
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It worked as advertised.
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Many THANKS!
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Sam,AC4OW
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Rick Williams - VE7TK
Ronald Taylor
Chris Raine W3PB
Randy K7RAN
Bruce Akhurst
Sam Hanie