Re: QMX+ with 100 amp/hour lithium iron battery
Hope you’ve got your fault protection sorted.?
Prospective short circuit will be 10kA and an auto fuse ain’t going to stop that arcing ..
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Re: QMX+ with 100 amp/hour lithium iron battery
"I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power output as discussed here." ? It generates slight RF noize. Which is annoying.?
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To: qrplabs@groups.io (qrplabs@groups.io);
Subject: [QRPLabs] QMX+ with 100 amp/hour lithium iron battery;
10.04.2025, 21:13, "Tom - AJ8X via groups.io" <tom.metty@...>:
I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power output as discussed here.
?
In hindsight, I like the adjustable buck-boost idea to solve both problems.
?
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Re: QMX+ with 100 amp/hour lithium iron battery
I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power output as discussed here.
?
In hindsight, I like the adjustable buck-boost idea to solve both problems.
?
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
This is set by the SSB drive level parameter (900 drive level is equivalent to 90%), as described on the SSB beta page.
So if I understand the description correctly, no, the modulator voltage will not exceed that set value.
Stan KC7XE
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Re: QMX+ with 100 amp/hour lithium iron battery
Thank you everyone for such prompt responses.? A buck converter is on its way!
--
Jim, W7EZN? ? 73!
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Re: QMX and power bank PD
The 12.01V is safe.
But are you saying that the voltage is dropping to 8.64V when you transmit?
This is safe, and will work, but will give you lower power-out.
How and where are you measuring this drop to 8.64V?
?
The voltage should not drop nearly that far, it should drop at most only to about 11V with a nominal 1m cable, if the battery is fully charged and can supply the current. ?The QMX will draw just under 1A at 12V during transmit.
?
This measurement suggests that the combination of your cable and your power bank can't supply a full 1A at 12V.? This should be easy for most power banks, so there may be something wrong with your cable or power bank.? But it should work with your QMX as-is, just lower power out.
?
Stan KC7XE
?
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Re: QMX+ with 100 amp/hour lithium iron battery
YES!
Mandatory.
Roger
8P6RX
Get
On 10 Apr 2025, at 13:46, "Jim - W7EZN via " < yahoo.com@groups.io target=_blank>jhowell39=@groups.io> wrote:
Just about to finish my QMX+ build and I have a voltage question.? The kit was built for 12 volts.? I have a 100 amp/hour lithium iron battery for vhf base station emmcom backup.? At full charge, its just north of 14 volts.? Would it be wise to install a buck converter in the battery box to limit voltage out to 12 volts for the QMX+?? ? Thanks in advance - I really don't want to fry this little gem.
--
Jim, W7EZN? ? 73!
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Re: QMX+ with 100 amp/hour lithium iron battery
Yes you should limit the voltage to 12V. A buck converter or just simply put some diodes in series will do the job.
--
73, de BD8BTE
op: Lun Yang
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
In normal operation the modulator voltage seems to be 90% of the main power, does the modulator voltage increase above that for the peaks of SSB?
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Re: QMX+ T507 winding direction?
If you use a binocular toroid isn't there also coupling between the two transformers?
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QMX+ with 100 amp/hour lithium iron battery
Just about to finish my QMX+ build and I have a voltage question.? The kit was built for 12 volts.? I have a 100 amp/hour lithium iron battery for vhf base station emmcom backup.? At full charge, its just north of 14 volts.? Would it be wise to install a buck converter in the battery box to limit voltage out to 12 volts for the QMX+?? ? Thanks in advance - I really don't want to fry this little gem.
--
Jim, W7EZN? ? 73!
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Re: Here's hoping for QMX+ v2
Wow! I just remember seeing the 10,000 figure on a post some time ago. That is really an accomplishment!
Jack, W8TEE
On Thursday, April 10, 2025 at 11:04:50 AM EDT, Hans Summers via groups.io <hans.summers@...> wrote:
Hi Jack et al
Thanks OM, encouraging comments :-)? I wouldn't be too concerned about Hans workload. Think about it. He has over 10,000 QCX-and-family radios out there and they all work "right out of the box". This includes the "standard" QCX, the "mini" QCX, and now the QMX.?
Gross underestimate :-)? ?To be strictly accurate: ? 21,343 QCX-series (QCX, QCX+, QCX-mini), debut August 2017 9,347 QDX-series (QDX, QDX-M), debut October 2021 8,922 QMX-series (QMX, QMX+), debut May 2023
So yeah, don't worry too much, I am used to a high workload... but rest assured: whatever new thing I develop, if and when, I will do so very quietly to avoid any pressure and stress; so you guys speculate all you like, but don't?expect any hints from me!
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Re: QMX+ MCU (? for Hans)
This type of request needs to be submitted to the support desk at qrp-labs, not this user-supported forum.
Stan KC7XE?
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Re: Here's hoping for QMX+ v2
I've had some discussions with Hans about what it would take to produce a very useful user-friendly digital communications "appliance" based on the QMX.? I think that one way to implement this would be to use a combination of a QMX and a Raspberry Pi Zero 2W running something similar to DigiPi ().? DigiPi uses a Pi connected to a transceiver, and allows several digital communications programs to then be run using a web browser (including the web browser on your smartphone) for the user interface.? My idea is to create something similar configured specifically for the QMX.? That would make it even simpler to use since it would be mostly preconfigured and it would only include programs compatible with the QMX.? It could also take advantage of features (like access to the console menus) that are specific to this radio.? Like the DigiPi, this could be distributed as custom image for the Pi that you just need to write to a micro SD card and stick into a Pi.? Unlike DigiPi, I hope that this would be freely distributed so that anyone could download a copy of it from a link at .? DigiPi is currently only available to people who support KM6LYW on Patreon.? I suppose that another version could be created that would include only the programs compatible with the QDX.
I plan to explore this possibility further.? However, I'm currently staying busy with my work on ardopcf (), so it might be a while.? So, if somebody else wants to work on this idea, that would be even better.? In that case, I'd be happy to offer further opinions about how I think that this might be implemented.
I'd be very happy to see something like this develop.?
I'm still happily using Peter's ardopcf modem program on my Pi400, with Pat WinLink client, both running UI in a browser. Works great with QMX+, very easy to use and most days except when there is a "propagation outage" I can use WinLink email via a 20m link to LZ3CB 635km away (my nearest WinLink server).?
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Tim, great idea re. the tab cutting. I have a couple of those upgrades lying around and will upgrade my QMX+ too.
Will post pics and results when done.
It will be nice to have a unit that isn't afraid of a little extra VIN. Hopefully I'll be able to run directly off of my LiFePo battery or a standard Ham supply.
--
Randy, N4OPI
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Re: Hand Mics for QMX SSB ? thank you all for the input.
Id like to thank everyone that took the time to answer my question regarding the QRP Guys mic.
Larry NA0F ?
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Re: Here's hoping for QMX+ v2
George,
Would you mind sharing the info for the 140$ PC you bought?
73! de Bekir TA2RX
10 Nis 2025 Per 18:36 tarihinde George Korper via <georgekorper= gmail.com@groups.io> ?unu yazd?:
I purchased an amazing $140 mini PC and use a USB cable. QMX + doesn't need a hardware change.?
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Re: Here's hoping for QMX+ v2
I purchased an amazing $140 mini PC and use a USB cable. QMX + doesn't need a hardware change.?
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Re: Here's hoping for QMX+ v2
I have to smile when I keep seeing requests for more power, surely the answer is in the name, “QRP Labs”.
Notwithstanding the 10W and 50W add on amplifiers, surely the radios themselves should remain true to QRP concept.
?
Unless we are going to see a new “QRO Labs” division…
Just imagine the amount of smoke likely to be generated then?
?
Best wishes to you all wherever you all live and whatever your views…
?
?
?
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Re: Here's hoping for QMX+ v2
I've had some discussions with Hans about what it would take to produce a very useful user-friendly digital communications "appliance" based on the QMX. I think that one way to implement this would be to use a combination of a QMX and a Raspberry Pi Zero 2W running something similar to DigiPi (). DigiPi uses a Pi connected to a transceiver, and allows several digital communications programs to then be run using a web browser (including the web browser on your smartphone) for the user interface. My idea is to create something similar configured specifically for the QMX. That would make it even simpler to use since it would be mostly preconfigured and it would only include programs compatible with the QMX. It could also take advantage of features (like access to the console menus) that are specific to this radio. Like the DigiPi, this could be distributed as custom image for the Pi that you just need to write to a micro SD card and stick into a Pi. Unlike DigiPi, I hope that this would be freely distributed so that anyone could download a copy of it from a link at qrp-labs.com. DigiPi is currently only available to people who support KM6LYW on Patreon. I suppose that another version could be created that would include only the programs compatible with the QDX.
I plan to explore this possibility further. However, I'm currently staying busy with my work on ardopcf (), so it might be a while. So, if somebody else wants to work on this idea, that would be even better. In that case, I'd be happy to offer further opinions about how I think that this might be implemented.
Peter LaRue
AI7YN
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Bruce Akhurst
Tom - AJ8X
jjpurdum