I know it sounds weird, but that's what my HB QMX does. I turned off my QMX when the band was switched to 10M. Next time I turned it on, the band was 10M as it was previously, but then I realized the S-meter stopped working - no single bar with or without the antenna, although the power/swr meter still worked fine on TX.

I turned on and off the QMX multiple times, toggled the S-meter and changed the related settings many times with no luck. Everything (including RX) seemed to be working fine except the S-meter, which was so puzzling.

I switched to different bands, only to observe the same symptom. Then once I turned off the QMX when it was switched to 20M. I turned it back on and tada! The S-meter came back.

So I tested it with other bands (turn off with a certain band to store it, and turn on with the band). This problem is replicated only and always with 10M. Is it just my HB QMX doing weird, or does anyone else find the same problem?

?

73,

Yoon KM6KJI

On Mon, Nov 18, 2024 at 09:18 PM, Jim VE4BWG wrote:

I am still scratching my head over how to get the QMX to transmit from the FT8CN app

I use FT8cn with my Samsung S20+ phone all the time with no issues.? It works great

I don't have to use the dongle approach, but that may be required by some devices to get their USB-C to switch to the OTG mode.

In the FT8cn settings I chose:? Control=CAT, Connection Type=USB, Rig=QRP Labs QDX

Then on the 'Calling' screen, I touch the icon in the upper-right corner to enable the transmit, and it just works.

Touching CQ will start my CQ on the next timing boundary.?

?

When trying to transmit, does your QMX turn on the little dot under the A to show that PTT was enabled? Does the other dot turn on to say it is receiving audio?? Of course if the dots turn into a line, then all is working...

One note: if I have all of the same settings, but don't plug in the cable to the QMX, the audio from the CQ comes out on the phone's speaker.?? That helps me know that I am operating the program correctly.

Stan KC7XE

On Mon, Nov 18, 2024 at 07:37 PM, Jerry Gaffke wrote:

This seems to be the first use of the acronym "ABS".

Yes, Jerry--I started using it a few weeks ago. I may have been the first.

?

Maybe the 'A' in the acronym "ABS" refers to the first character in the acronym "ATU" so ABS is an acronym referencing acronym! (A "nested" acronym?) ;)

?

(A)TU (B)attery (S)peaker.

?

I have no idea how Sardar feels about it but it just rolls off my fingers and onto the keyboard so nicely. Plus, QMX+ABS isn't bad either.

?

73,

Cal (AD8Q)

You might actually need an OTG cable off the tablet. My limited experience with interfacing radios to tablets have always needed an OTG cable.

?

73 de VE4ACE

On Mon, Nov 18, 2024 at 11:00 AM, <me@...> wrote:

Could you draft your schematics?

Sure.? Here is the idea - this addresses the issue of having 12V 'hot' on the power-in jack from the batteries, even when nothing is plugged in.? And the prior observation was that if you leave an 'off' state power source plugged in, it can drain the batteries, which you may have just charged up with that same power source.?

?

I think this would be a good option to include - and it can be ignored by those who don't need it.? It is quite easy to implement, and even to 'dead-bug' on the current design.? The general idea is to put a diode in series with the center pin of the power connector to protect it from the 'back-emf'.

?

Unfortunately, the only way to separate the power-in jack center pin from the battery voltage, while allowing the jack to be used for charging and powering the QMX+ is to cut the center pin tab where it is soldered into the board.? Then re-route the input power from that center pin, through a diode, and back to the Vin bus and batteries.

?

The attached schematics and diagrams show the idea.? This method uses a jumper wire from the center pin up to the companion board, where it connects to a diode that feeds the batteries and Vin.? When the ABS boards are not installed, just plug the jumper into pin 1 of J101, and it works like before.

?

I guess such a diode could just be directly installed between the center pin and its pad on the main board with the same effect, but it may be a bit finicky to install.

?

Hello,

?

I've been struggling with FT8CN (on my Galaxy Tab A7 Lite) and my QMX. Initially I had no waterfall, thus no receive data no matter how loud the volume I selected on the QMX. Then I found that there is a protective feature built into the sound settings in the Android system settings. Go to system settings for the Android OS. Select "Volume". This will bring you to the individual settings page. At the top-right of the page press-select the "3 vertically oriented dots". That will bring you to the "Media Volume Limit" page. Here you will select a PIN and once entered you will be able to move the volume slider ("Custom volume limit") fully to the right. Now the Android system will accept the higher QMX volume required for FT8CN to receive data and decode. Save the PIN that you set.

?

Of note: The Galaxy Tab A7 Lite has a USB-C connection and when I initially used a plain USB-C to USB-C cable, the receive function of the app was inoperative. I put that cable aside. Then without plugging anything into the tablet, I switched to a USB-C to USB dongle in combination with a USB-C to USB cable. I plugged the USB-end of the cable into the dongle and the USB-C end of the cable into the QMX. I turned on the QMX (already set to Vox off). Then I plugged the USB-C end of the dongle into the port on the tablet (FT8CN should still be off at this time). Seconds after the cable was plugged into the tablet it asked me to choose a serial port. I did that and FT8CN started up - and after having done that I had no problems with the FT8CN receive function (you may have to adjust volume on QMX).?

?

I am still scratching my head over how to get the QMX to transmit from the FT8CN app. I think I have run out of things to try and I am open to suggestions.

--

Jim

VE4BWG

The good news is that the LPF sweep looks great, and so does the diagnostics page.? So hopefully your transmitter section is all OK.

The bad new is that all of the receive related scans are bad, and generally show 'noise'.? This includes the RF scan, the IQ scan, and the image rejection.? Since these are all bad, it could really be anywhere along the receive path: L401, T401 (trifilar), and the PCM1804.

?

I would start by examining carefully the trifilar toroid, and make sure you paired the wires correctly, and that they are all soldered in well.? Reheat the joints to make sure the enamel burned completely off the wires.? Same for L401A (it does 20M).? If you are very confident in those, it may be the PCM1804.? The only way I know to measure for sure is using an oscilloscope and signal generator as mentioned last time.? Or you could just replace the PCM1804 and see if the problem goes away (but that is quite a fine-pitched chip to replace, so take care and practice on something else first, or get someone else to do it for you).

?

Stan

This seems to be the first use of the acronym "ABS".

My best guess is that it stands for "Antenna tuner, Battery, and Speaker".

Is that correct?

?

I suggest you put ABS at the start of the subject for every thread that pertains to this.

Makes it easier to find discussions about it.?

And perhaps for some, easier to ignore.

?

Anyways, looks like a fun project.

You're making good progress.

?

Jerry, KE7ER

?

?

?

On Sat, Nov 9, 2024 at 11:16 PM, Cal (AD8Q) wrote:

Hello All,

I have built my QMX Mini (high band) and I configured T501 for 9 volt operation. ?
I want to re-configure - actually build a new one - for 12 volt use, and preserve the original.?

My question is about the T501 core material. ?Is it #43 mix or #73 mix? ?I have searched out the bino core in DigiKey Canada and the only bino core that fits the description of BN43-202 comes as #73 mix.

?Is this (#73) the correct core mixture for the T501 transformer?

Advice?

Thanks,

Dan VE7CTN?

?

On Mon, Nov 18, 2024 at 06:07 PM, Tisha Hayes, AA4HA wrote:

Cal and Sadar, thanks for all if your hard work on this.

You are welcome, Tisha! I'm pleased you've found the new PCB group buy thread. Things are really coming together now!

?

73,

Cal (AD8Q)

Here is a new Digikey BOM link. It contains the second CD4066BE and its socket for potential future feature expansion.

?

Assuming that it continues to load the Digikey page (it does now), don't use the old link. It's well worth the extra dollar for these two parts to enable new features, if they are released, so use the link above in this post.

?

Again, I will also post a smaller Amazon BOM and some notes, re-written from my similar post on the original thread, but I will probably not get to it here for a couple of days or so.

?

73,

Cal (AD8Q)

On Mon, Nov 18, 2024 at 05:54 PM, <me@...> wrote:

not really. The second one U6 is for controlling bypass button on ATU. It can be omitted or soldered later. 750 ohm resistor is more important.

Good to hear, Sardar!

?

I'll post a link to my corrected Digikey BOM. Unfortunately, deleting the saved cart that I used to generate the old link does not seem to affect the operation of the link. Neither did revising that cart, which I tried before I deleted it. The old link does have the 750 Ohm resistor, though.

?

The other good news is I found my DIP sockets, but I don't think I'll have time to play with the bypass button or ATU code for awhile anyway.

?

73,

Cal (AD8Q)

Thanks for any help and insight.??

PK

Finished my build completed all indicated checks more than once. On initial transmit into a dummy load saw about 4 watts on a very inexpensive MFJ QRP Meter. ?Within seconds it appeared to drop to zero. Went and got a better wattmeter from a friend and measured 1/2 watt this evening. ?Windows PC, all LED indications are as specified. ?Hooked up a small vertical and saw a good signal on my main station and it is decoding as expected. Checked 20 and 40 meters. ?Obviously something got off on the construction (one would think). Inspected the board for solder traces ect and could see no obvious issues?

?

any idea on what my next steps would be. ?If one or some of the PA transistors are bad they would be ez enough to replace, but, something obviously caused a failure and at this point I have no clue,

?

TIA for any and all responses

?

KX4BE

I have a new QMX+ and I'm trying to configure it for Digital and CW.? I'm using the same settings that work in my QMX.

?

I can receive Digital signals but not transmit.

?

In CW mode, I can neither receive or transmit.

?

Does anyone have a quick rundown of the correct menu settings?

?

73

?

N2JHR

?

--Jim

The above thread was recent with many soeaker examples?

Cal and Sadar, thanks for all if your hard work on this.

--

Tisha Hayes

AA4HA

I'm using a cheap radio as a speaker for the QCX-mini.

You can also record. It is a model called RETEKESS V115.

Mitsu JK1PDR