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For my 9V QDX, I bought an Anker Power Bank with PD output. This can supply 9V @ 2.2A, so around 1A in transmit from my QDX is just fine. It goes for hours of FT8 use on a charge:?
Then I bought a PD cable that has USB-C on one end, a 9V chip in it, and a 2.1mm/5.5mm connector on the other end, which goes directly into my QDX.
This worked great for me so far, and I like that I can use the power bank for other items when traveling.?

Nate
N8BTR

Andrew,

Welcome to the wonderful world of CW! I've just jumped back in this year after a 20+ year hiatus.

The QMX (mine's not a +) is a fabulous CW machine.

Good job getting your voltage at 12v or less. It sounds like you have all the pieces put together.

As long as you don't transmit (don't plug in a key), I don't think there's any possibility whatsoever of hurting it. Listen away with any random antenna connected.

I've been using a home-brewed EFHW for 10/17/20/40 on the vast majority of my pota activations. I cut it to be as resonant as possible: under 1.5:1 on most deployments. I use it without a tuner. With each new antenna installation I do use the QMX's built-in SWR check to verify everything is where it should be. Occasionally this has prompted me to re-adjust how the antenna is hung or how taut it is. Having the built-in SWR protection is nice, though occasionally I turn it off when windy conditions give me little transients that trip the protection.??

With nearly 1000 QSO's so far this year, the QMX is doing terrific: no issues. It is a durable little machine with only a little care.

Early on, I had several local friends encouraging me to step past my anxiety and throw out some calls. I highly recommend Parks on the Air (pota.app). It's usually very scripted, and people are out there wanting to hear from you.?

This was an encouraging primer:

But the most fun way to get started is to find a local buddy and do a joint activation. The encouragement and advice is invaluable.

GL es 73 de Todd W2TEF

Success (so far). I replaced IC503 and now have a nice 5v TTL level signal out on both sides. BS170s not installed yet. Waveform attached.
This was on 20m. I tried 6m and it was bit lower amplitude at 4v. But still much better than before.
The IC501 and IC502 XORs also have a nice clean output now.
Onward..

--
Randy, N4OPI

I have been watching patiently as my position in the wait list lowered from 800+ down to the 40s only to receive an email today from Hans advising the unit has shipped.? During that time, been reading a lot of the threads on various issues and concerns regarding the device.

So being a first user of CW (currently learning through LICWC), I am a bit intimidated/worried of doing something wrong and damaging my soon to be received QMX+.? I have already prepared my 12v (actually it delivers around 13.8v) Bioenno battery to put out 11.6v via a step down voltage regulator. Had it set to 12v, but cautiously dropped it down a bit.? I also have an EFHW 10/20/40 from Packtenna as well as their 29' random wire EF antenna.? For the random wire antenna I also built a TennaDipper II to use with a manual Z-match tuner as my Elecraft T1 may provide too high of a SWR during tuning.

So for now, I just want to be able to tune and listen to CW with the goal of first understanding what I am hearing before I attempt to make my first contact.

Any suggestion on how to proceed and setup the QMX+??

I will be working from my backyard and have preset mounting tubes for the CF mast to work with the EFHW and 20' of RG-316 coax.

I've put the PSU Test Process information into the wiki where it should be more accessible.? I changed it to say that the linear? VDD may be between 3.0 and 3.3V. Comments about the voltage as read by the MCU aren't relevant to tests done on the boards stand alone, that needs to be elsewhere.

Interesting; thanks for bringing this issue up.?

The issue manifested itself in my shack with Log4OM logging software. The CAT control is working, but the frequency fields for a new qso in Log4OM never got copied from the top of the screen... yielding many of my log entries being recorded as 0 KHz.?

When I read this topic, I immediately changed the frequency delimeter in my 2 QMX radios to a comma, the default, from a dot, and now Log4OM records the frequency correctly in my qso logs when my QMX is connected.?

Thanks for sharing this issue!?

And thank you Hans for catching this issue and having it fixed in the next FW release for the QMX series.?

--
73
de Roy - KI0ER
Littleton, Colorado USA

On Tue, Jul 2, 2024 at 05:42 AM, <w8gu@...> wrote:

OK.? This is something that I did not understand.? I assumed that the /LIN_REG_EN (I always? use / to indicate an active-low signal) was turned on during the startup test and then turned back off when it failed.? My understanding is probably wrong.

LIN_REG_EN is active high, not active low. At start up it is pulled high by R101, the processor pulls it low to disable the linear regulator and switch to the SMPS.

One other thought.? The processor is apparently calculating the max duty cycle based on the input voltage.? It thinks the input voltage is 8.1V, but it is wrong because the linear supply is only putting out 3.01V.? The input voltage is only 7.55 volts.? I wonder if 49% is high enough for an input voltage of 7.55V.

This will be correct while the linear regulator is enabled. Once it is disabled and the SMPS enabled VDD will be whatever the SMPS supplies.? However if the Vref for the ADC is VDD then the value of VDD measured by the processor will always be 3.3V regardless of what it actually is.

What will happen is that ADC_3V3, which is used to measure VDD, will always be 50% VDD because it is defined by the voltage divider R110 and R112, both 22k. The processor will read ADC_3V3 using VDD as the reference, then double it to get VDD.

I hope, and expect, that this is incorrect because the regulator can't regulate itself.? Perhaps Hans could comment.

As for my PSU test process, I'll update it based on these discoveries, and see if I can get it into the wiki where it may be more easily accessible.

I've learnt a lot about the subtleties of diode voltage drops and MOSFET operation from this.

Chris, G5CTH

It makes no sense to me, but following David's advice, I used the command line amixer cset numid=3 100% from the command line and now it works. ?\_(ツ)_/? .

Thanks for the help!

73s,

Jim
KE4MKG

Hi Mark - so I tried the alsamixer and it shows the QDX as having a zero setting and I am unable to adjust it:

Think you are right on the money here, just don't know what to do next.?

Sincerely,

Jim
KE4MKG
?

I'm using 8 Ikea NiMH 2500 mAh batteries with mine. I just exceed the recommended 5W output on 30 metres when the batteries are fully charged, but I don't run data modes, so I'm not too worried about popping the finals...

I've been operating at the kitchen table for the last few weeks, as the basement shack is too cold with the air conditioning running. I've had 2 QMX-to-QMX QSO's with W2TEF on his park activations...

I like the specs on the UPS power supply mentioned by Jared, tho. Will look into that...
va3rr

I have been using a battery backup for Wi-Fi routers. Something similar to this -
Mini UPS Battery Backup 37Wh Uninterruptible Power Supply for Router, Modem, Security Camera with Input 9V DC Output 9V DC Max.3A (No Charger)

I normally found them at about half this price, which is why I'm using it.?

For those that chose to go down the 9v pathway - I’m curious what energy source solutions you are using for field/POTA/SOTA type operations.

Very odd behaviour... How does it behave with earlier firmware installed on the radio??

Ronan
MM0IVR?

Look into TN? 0110? (Microchip N channel mosfet)? type 92 plastic case? ?from? Mouser or? digikey.? Probably hard to find on ebay.? ?Check pinout - different. These have diff capacit.? parameters and are harder to drive with the QMX drive cct above? 14 Mhz .? THe have Vdg of? 100V not 60V and are MUCH harder to kill. Several people have used them .?

John Z used the in a Qcx? I believe.? If you are targetting? 10mtr band ignore. If 60 and 40 mtrs a re your thing then it's a goer.? The actual? power out on these bands may increase marginally.? you can carefully lap a small flat on the back of the using wet sandpaper and? a glass underlay to the sand paper.? This to increase heat transfer? as they go into the PCB upside down c/w the BS 170.? If you don't look? after them thermally obviously you will pay price in shorter life.

obviously all subs to the basic design are at your own risk. Always start up at? 7V? and current limited after any major changes.?

you? canna mix and match the two TTL gate drive mosfet models.

I've got AGC's fitted to all my QCX's, 3 minis and 2 classics. They're pretty much essential.

As for the TCXO, my minis have them fitted although they've never really been used for WSPR where that would be important. For CW use, you're fine without.

Good to hear people are still opting for the QCX kits. They're solid performers and amazing value.

Ronan
MM0IVR?

On Tue, Jul 2, 2024 at 04:42 AM, Peter HB9EBE wrote:

/g/QRPLabs/message/119189

Need to try that !

On Tue, Jul 2, 2024 at 11:37 AM, Danny Bower wrote:

Yes very possibly. I should note for completeness this is on my QMX+

In the case of QMX+ LPFs this could be even more unpleasant situation:
3.5 x 5 = 17.5
3.5 x 7 = 24.5
7.0 x 5 = 35.0
7.0 x 7 = 49.0
I hope this will be solved in due time.
--
73 Bojan S53DZ

Hi,
there is for me a really annoying issue with the SWR and LPF scans.? It is connected with the DISABLE/ENABLE band settings and the SWR scans.? When all the bands are not enabled than the SWR scans are outputting garbage.? It only helps to enable them all and do a power cycle.? But in case you have to disable one band or two (as for example 160m) then it is dangerous to do the SWR scan there since the scan begins automatic at 160m band and not at the lowest enabled band.? I think it calls for top priority.
--
73 Bojan S53DZ

Hi Ludwig
Attached is a file with the pix inserted.? The file names explain which each is.? I hope they're helpful.
Regards
Greg

There has been a lot of history of? ?disgusting people buying? 2n7000 and relabelling them as BS170.? The pin out is different. Most of such people live in? ?PRC others in Vietnam.... as Marisa? Tomei said? IT's a FACT !

TEF