Re: Learning things the hard way - Triple checking
On Sat, Dec 7, 2024 at 04:30 PM, Hans Summers wrote:
I don't like the use of needles which can risk damaging the PCB which could make things worse.?
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Hans Hi
Steel needles are not for punching through the solder filled holes
It is for; you heat the pad, then insert the steel needle through the melted solder gently, solder won't stick to the needle, when solder cools down, you pull the needle out, you have a perfect hollow hole :)
I perfected this technique changing BS170s :)
73 DE muhsin TA1MHS
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On Fri, Dec 6, 2024 at 06:58 PM, Lasse wrote:
Had to turn off SWR protection in the radio to get the tuner to work but it doesn't seem like this was a problem.
I find my ATU 10 tunes up perfectly well with the QMX set to 'Tune Mode'. I use 12.03v supplied by a Nitecore PD powerbank.
? ? ? ? ? ? ? 73 de OE6FEG
? ? ? ? ? ? ? ? ? ? Matt
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Thanks for the kind words.?
It was fun to fiddle. And I believe does usefully reduce the internal thermal loading.?
I'm also working on a mod for a QDX where the same fan is mounted internally,. It's attached horizontally, with super glue,? to left side of the LED end plate near the? top cover. Plenty of room right over the open area on the main PCB at the 'top left'. Its wired to an additional input barrel power jack that is mounted on the other end of that side plate above and to the left of the LED..?
I'm currently powering it with a really inexpensive, dinky 5V Power bank so I can easily turn the fan on and off without glitching my main INIU Power Bank delivering 9V from the primary USB C output port via a 9V PD trigger cable. That battery has lasted for hours and hours and is still at 50% charge.?
Relatively easy easy to implement.? But since the case isn't opened up fully on the one side with the bottom of the main PCB getting air flow like the QMX mod, finding a good combination of cooling holes has been challenging and requires more eval. Delta temp drop times are longer.?
And I may need extra case or two for future trials :)
GREG
On Sat, Dec 7, 2024 at 5:23 PM, Karl via groups.io <karlshumaker@...> wrote: I think that is a super mod! You prolly gave Hans an idea!
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73
Karl
KI4ZUQ
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Re: It was dark as a pitch, with the p turned upside down, so I had to compromise, using a few alligator clip leads.,...
QSL, Mike and thanks !
I just finished working 10m thru Top Band using the QMX-Plus. The Magic Band wasn't open here today :0(
Nite all !
72,
Bill, N4QA/4 in OKI
Attached is m y old Elementary School ( Go, Riverlawn Rams ! )
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Re: It was dark as a pitch, with the p turned upside down, so I had to compromise, using a few alligator clip leads.,...
Hi Bill,
That is a fantastic picture of you and your dad. It¡¯s a real treasure. He had to be proud of you following him into ham radio. The six-shooter and truck are fun. Those have to be fond memories. I enjoy POTA hunting. I will look for you. I am mostly on 20. 72¡¯s
Hi, Mike.
No tuner but the Oak Hills Research WM-2 QRP Wattmeter indicated equal forward and reflected power (? about three watts ) so I imagine VSWR was very close to Lazy Eight !
72,
Bill, N4QA/4 in Oak Island, ( OKI ) North Carolina USA
ps,
The attached photo is of my dad, Mel, W4MAI ( SK 2004 ) and me at Christmas when I was 2 years old. Notice my six-shooter and pickup truck.
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Re: QMX+160-6 ceased powering up
#QMXplus
Thank you SO much for all your help, i really appreciate.
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I can measure current on the 12V input.? I have a digital oscilloscope also.
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Anyone else wants to pitch in ??
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Thanks,
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Sly VA2YZX
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Re: QMX+160-6 ceased powering up
#QMXplus
Well, I guess it is good that D109 is really working.? That removes one more variable
I wouldn't jump to the conclusion that it's one of the major ICs yet (because I'm stubborn: it could be one of them, but they are normally less likely to fail, so I usually try everything else first).
But I also don't know what else I can have you try that only requires a DMM, and not difficult part removal.
Do you have a way to measure the current that is being drawn, before and while you press the 'on' button?? It would be interesting to know, but may not lead directly to the problem.? My next step would be to use an oscilloscope to look at some signals to ascertain which of my #1 or #2 hypothesis (of the previous post) is correct, if either, and then, based on that answer, to selectively start lifting parts legs to find what will change the behavior.?
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Other than that, I am out of ideas for right now.? Maybe someone else can think of something.?
Stan KC7XE
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Re: QMX - Any progress on key clicks please?
Here is the video of my popping QMX.
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72
Myron WV?H
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I think that is a super mod! You prolly gave Hans an idea!
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73
Karl
KI4ZUQ
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Re: Diagnostics fail with no BS170s installed
#qmx
Thanks for the feedback.
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I've got 10 MS5351Ms on their way from China.? Not holding my breath.
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I had a? bit of a fright using the protocol analyser on my scope, Was setting up I2C analysis and decided to try a larger sample depth - and it hung up.? I still had a display on the screen but no trace and none of the buttons worked.
Looked up the copious and incomprehensible hacking descriptions on EEVBlog and managed to get the USB control working and tried the SCPI commands. Some worked but others caused it to hang.? One I tried was PRIVate:FACTORY:RESET.? This also appeared to hang.? I left it for a while, then came back and it had healed!? Screen display, buttons working and so on.? Phew!
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All I can suppose is that things were running very slowly because of the large sample depth and leaving it alone gave time for it to work through to a reset command.
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Chris
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Re: QMX - Any progress on key clicks please?
Hans knows the issue and the fix.? It is on his list and not forgotten.?
He removed most of the pulse shaping on the sidetone while addressing a different issue, which resulted in the 'click' part of this problem.? He just needs to restore that shaping.
The DC bias 'thump' issue is in hardware, and requires the larger bias capacitor we have described, or a Vin source that can't droop during tx.?
Stan KC7XE?
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Re: QMX - Any progress on key clicks please?
Hi Myron,
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Further up this thread, Hans has indicated he¡¯s aware of the issue and it is on his list. It has affected me too since the beginning of my QMX revision 1. ?The issue has been raised in the group from time to time, but not many users have complained of it. I think that has slowed down the process to find a resolution. Hans has indicated he¡¯ll look into it once the SSB development is complete. In the interim, I intend to apply this cap fix.?
John
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Re: How many Turns to take off a Toroid?
Hello Steve
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Yes I agree it is optimized for 15m, but not intentionally, as you see both of the QMX+'s show 15m the best. I tried to optimize all three bands? in that LPF set, but it wasn't easy. I am tempted to have another go at it to see if it can be improved on 17/20.
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But glad you are happy with yours.
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73
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Ian G4GIR
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----- Original Message -----
Sent: 07/12/2024 18:23:14
Subject: Re: [QRPLabs] How many Turns to take off a Toroid?
Ian,
My LPF plots are very similar to yours. Here is my current power output. I removed some turns on the 40m and 20m toroids.
160m - 6.0 W
80m - 5.3 W
60m - 4.9 W
40m - 4.9 W
30m - 4.5 W
20m - 4.6 W
17m - 2.7 W
15m - 2.4 W
12m - 2.2 W
10m - 3.7 W
6m - 3.0 W
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The only band I am disappointed in is 15 meters and the 2.4 Watts.? My LPF plot is very similar to yours, so how did you get 5.3 Watts out of that band? When I optimized the LPF for 20 meters, the power actually went down on 15 meters, but the LPF plot for 15 meters doesn't indicate the cause for the decrease in power.? But I think your 20-15 meter LPF is optimised for 15 meters as your 20 meter power is less than mine.
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As far as the procedure for modifying the toroids, I studied Hans' YouTube video on optimizing the QCX+.
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The more I understand this radio, the more I like it. I now think my radio is 100% normal.
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Steve, W2MY
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Here's some pics of a cooling mod I did on my HB QMX.? It involved spacing the bottom cover away from the main PCB with small nylon standoff which opens up the sides for airflow.?
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I figured its ugly sweater season so . . .? perhaps my butt-ugly mod will be looked at with kind eyes. :)
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The 'yellow' bits were cut out of 2mm ABS modelers plastic sheet. There is a piece behind the proto board to provide insulation from the case.?
The fan is a 25 x25 x 10mm, 5V mini fan that I found on Amazon. It draws just 28ma and is very, very quiet, both acoustically and electronically.?
The cool air is drawn in right over the PA transistors. ?A 4 pack was about $10 US.?
The USB A connector and proto board were sourced from Adafruit. The USB connectors were cheap. Their 1/4 size proto board is a bit pricey but oh so useful.
The side support legs of the USB connector were bent to fit down across 2 holes each on the proto board and soldered down.
I only soldered in the two power leads of the usual 4 as I obviously did not need to pass data.?
If you look closely at the inside view of the bottom cover you can see that I mounted the fan and proto board to the side of the bottom cover with screws and nuts which provided good mechanical support. The large, yellow cover on the side next to the fan was simply super-glued to the side of the case bottom.
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I power the fan with a separate USB A to 2.5 mm power plug.? If I use the same INIU Power Bank in its USB A output port that I use for providing power to the Q, I found that it was necessary to plug in the fan cable first and then the 12V PD trigger cable on the main USB c output port for the main power intp the Q.? Otherwise, there is often a glitch that drops the power to the Q.?
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Not related to cooling, but you may notice that I replaced the power in jack with a panel mounted 2.5mm power socket that I carefully connected to the main PCB power pads with flexible, 18 AWG, insulated wire runs. No chance of loose connector related power issues.?
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I have measured the temperature of the exhausting air dropping back to the 'receiving condition' temperature occurs with a TX duty cycle of around 25% on WSPR.
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I have also done simulated dummy load runs of FT8 CQ's that last about 6 minutes before WSJT-X stops the CQ'ing because of "No Response" and found that the exhaust side air temperature rises about 4-5 degrees, then drops back to the 'receive condition' temp after about 3-4 minutes.?
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All my testing was on my benchtop at about 23 - 25 degrees ambient. The temperature probe is just a simple thermocouple nichrome wire. Probably not dead accurate, but I was only interested in relative changes.?
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YRMV ....
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73 GREG KI4NVX
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Re: How Does Voltage Get to the Finals?
#QMXplus
Steve,
The turns ratio of T501 from primary to secondary is higher if you build the radio for 9v instead of the more typical 12v.
That higher ratio means a 9v build running on 9v has about the same power out as a 12v build on 12v.
The turns ratio of T501 is the only difference between a 9v build and a 12v build.
The first thing to blow if you exceed the recommended power supply voltage (9v or 12v, depending on build) is the BS170 finals,
as they will be working too hard.?
Everything else in the radio should be fine at a somewhat higher power supply voltage.
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The modulator at Q507 can be used to reduce power, such as when adjusting an antenna tuner.? Q507 is a linear voltage regulator that adjusts the voltage to the BS170's as a function of DAC signal coming from the STM32F processor.? It can only reduce the voltage to the finals, it cannot increase the voltage to the finals above that of the 9v or 12v power supply that you provide.
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Jerry,? KE7ER
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Re: How Does Voltage Get to the Finals?
#QMXplus
On Sat, Dec 7, 2024 at 10:59 AM, Steven, W2MY wrote:
2) Why are there so many warnings about not going above 12 Volts (I assume for the 12 Volt supply), but no warnings about going over 9 Volts for the 9 Volt supply?
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Exceed the limits of the BS170s and they expire more readily.? Higher voltage is
more power also when there is SWR issue higher current.
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For 9 or 12V the transformer ratio is used to limit power at a given voltage.
The voltage to the final is not the same for 12 or 9V.? If that were the case
there would be no need for different transformer.
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3) Is everyone else getting 7.5 Volts to their finals regardless of input supply voltage, or do I have a problem?
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Nope!? But it is controlled by the MPU DAC output.
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--
Allison
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Post online only,?
direct email will go to a bit bucket.
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Re: QMX - Any progress on key clicks please?
I have had those leading-edge audio thumps since the beginning of my QMX (v27 FW) as well and wondered if it was going to be fixed but it doesn't even look as though its on the list to get fixed. To me it's a big problem and would welcome a software change rather than hardware fix. I will post a YouTube video demonstrating the symptom when I have a chance.
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72
Myron WV?H
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Re: How Does Voltage Get to the Finals?
#QMXplus
Steve, the power to the finals goes through Q507 to L502 and then to the center tap of the primary of T501. The two ends of the primary winding of T501 then go to the drains of the finals. Look at the schematic to follow it per the above. The schematic label is "+12v" but that implies?+9v if that's the supply you are using. There will be some voltage drop along the way, but the voltage at the finals will be a little less than whatever the input voltage is set to.? Also, the DC voltage you measure at the drains of the finals will be affected by the RF at those points. You would be better measuring that at the T501 center tap or at the drain of Q507. In the photo it appears you are getting 6.0 watts output, so I don't think you have a problem.
The warnings?about over voltage apply to both voltage levels used.?
73 .. .Ron
On Sat, Dec 7, 2024 at 11:59?AM Steven, W2MY via <stevenpituch= [email protected]> wrote: One thing that I haven't figured out yet is how the power gets to the finals. I don't understand how a 12 Volt supply is equivalent inside the radio to a 9 Volt supply.? Yes there is a transformer that is wound differently for either type of supply.? But is the voltage delivered to the finals the same whether the supply is 12 V or 9 V?
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The reason I am asking this is that I choose a 9V supply.? I use a 4 cell lithium ion pack (16.8 V) and I have a voltage regulator to bring this down to 9.00 Volts.? When I go into the Putty diagnostics, the voltage at the finals is always shown as 7.5 Volts, regardless of the band.? I checked and the voltage supply stays a constant 9 Volts during key down.
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So my questions are:?
1)? Is the voltage to the finals the same regardless of the voltage (9 oe 12) chosen for the power supply?? ?
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2) Why are there so many warnings about not going above 12 Volts (I assume for the 12 Volt supply), but no warnings about going over 9 Volts for the 9 Volt supply?
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3) Is everyone else getting 7.5 Volts to their finals regardless of input supply voltage, or do I have a problem?
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Thanks for all the help.
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Steve, W2MY
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How Does Voltage Get to the Finals?
#QMXplus
One thing that I haven't figured out yet is how the power gets to the finals. I don't understand how a 12 Volt supply is equivalent inside the radio to a 9 Volt supply.? Yes there is a transformer that is wound differently for either type of supply.? But is the voltage delivered to the finals the same whether the supply is 12 V or 9 V?
?
The reason I am asking this is that I choose a 9V supply.? I use a 4 cell lithium ion pack (16.8 V) and I have a voltage regulator to bring this down to 9.00 Volts.? When I go into the Putty diagnostics, the voltage at the finals is always shown as 7.5 Volts, regardless of the band.? I checked and the voltage supply stays a constant 9 Volts during key down.
?
So my questions are:?
1)? Is the voltage to the finals the same regardless of the voltage (9 oe 12) chosen for the power supply?? ?
?
2) Why are there so many warnings about not going above 12 Volts (I assume for the 12 Volt supply), but no warnings about going over 9 Volts for the 9 Volt supply?
?
3) Is everyone else getting 7.5 Volts to their finals regardless of input supply voltage, or do I have a problem?
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Thanks for all the help.
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Steve, W2MY
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Re: It was dark as a pitch, with the p turned upside down, so I had to compromise, using a few alligator clip leads.,...
Hi, Mike.
No tuner but the Oak Hills Research WM-2 QRP Wattmeter indicated equal forward and reflected power ( about three watts ) so I imagine VSWR was very close to Lazy Eight !
72,
Bill, N4QA/4 in Oak Island, ( OKI ) North Carolina USA
ps,
The attached photo is of my dad, Mel, W4MAI ( SK 2004 ) and me at Christmas when I was 2 years old. Notice my six-shooter and pickup truck.
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Matthew Pullan
Bill, N4QA/QRP
WV0H
Karl
Ronald Taylor
Steven, W2MY