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Re: Simulation of #QMX Filters + planned 6m in QMX #qmx

 

Peter,?
I recall some discussion about this in QDXs maybe in the past...and some thought that the impedance is NOT 50 ohms, and/or, not acting like it on that input.......?
Keep us posted with what you are able to do.... I've figured out that one could cover all bands 160-6 with the 6 band setup screen as far as generating the signals.... but the filtering for BPF and LPF would require a whole separate set of filter boards....And thus the QMX+ :-)
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-Nate?
N8BTR
Re: mic test doesn't scroll up

 

When I use screen in Linux, sometimes the terminal window is slightly out of shape and the mic tests does what you're describing.
Re: Simulation of #QMX Filters + planned 6m in QMX #qmx

 

Hi Peter,
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Here is an LTSpice XVII simulation for the QDX High-Band filters. I've included a PDF printout in case you don't have LTSpice.
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73
Evan
AC9TU
mic test doesn't scroll up

 

This probably some configuration with my terminal emulator.
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When running the mic test I get the bottom row. However, it does not scroll up. So I don't see the history covered on the beta firmware page.
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I've tried a factory reset. I'm wondering if anyone has this issue and knows how to resolve it.
Re: New Build, No Flash Drive found #build #building #qmx

 

Hi Russ and Stan.? thanks for the support.? I do seem to have proper resistance between VCC adn VDD and ground.? I have ordered new boards (and in fact a whole new QMX kit just in case).
I also detected a poorly connected leg of the binocular T507 transformer.
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Hoping I didn't cook the entire radio, but will have to wait for the new boards.? I have successfully built the QCX mini and the (tr)uSDX, so crossing my fingers that I didn't fall apart on the QMX
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Thanks again for your answers.
JD
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

I agree that would have been easier... but it's done now LOL... I agree, if I need to do it again, that's the plan.
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I am happy to report that the quadruple BS107 transplant seems to have been successful :)
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Running the calibration now... hoping for the best.
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73,
Joel W9JFK
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

When I use my Hermes Lite 2 or a Tiny SA it appears that my audio goes way beyond 3 KHz on USB for example both above and below my center frequency. However checking on a remote WebSDR I see what looks like a clean well defined SSB/USB signal and all my audio reports have been good.
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73,
Jim AC9YY
Re: Simulation of #QMX Filters + planned 6m in QMX #qmx

 

Today I soldered the original BPF configuration into my QMX 20-10.
Preliminary I bypassed the 20m LPF, and I left out the two other LPFs.
I configured all bands to use the LPF bypass and can sweep through the BPFs through all bands.
Everything works fine as I am used from the QMXs, but not as simulated ;-)

The band pass filter is much steeper than my simulation!
=> My assumption is wrong: I can't use the 10m BPF for 6m.
Maybe my configuration for the simulation is wrong?
- Did I use the right impedance (50 Ohm)?
- Is my circuit for the simulation correct??
I understand the BPF like this:
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RX IN ------ L ------ C ------- OUT
GND ---------------------------- GND
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Is this too simplistic? Is T401 to be seen as essential part of the BPF?
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73 Peter DL4PJ
Re: Qmx Ssb intermittent transmit.

 

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Try tightening up the ring contact on the 3.5mm jack. ?If you reach in with a very small barrow blade screwdriver you can bend that contact out to place more tension in the plug for a more reliable contact.

That fixed my intermittent on the QMX. ?On the QMX+ I installed Kobiconn jacks (Mouser) on the rear panel. I used the TRRS jack for even more retention of the plugs.

Dave WI6R

On Mar 25, 2025, at 08:26, Petrov Sergey via groups.io <irtish71@...> wrote:

?The same with me. Smtm you need to press PTT twice to start tx.

16:35, 25 March 2025, "Howard Lamhut via groups.io" <howardlam@...>:
蚕惭齿…
I have the SSB software installed version three and made one contact with good audio reports.
The only thing that is strange is sometimes the radio does not go into transmit when I press the PTT in Ssb mode. In CW mode it works every time 100%.
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--
Sent from Yandex?Mail for mobile

Re: QMX+ Rev.3

 

I just wound L506 with 42 turns....only because the solitary yellow core was already used making L403 !
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

I wouldn't worry to much. Hans wrote regarding the calibration "The results are markedly different by band, this is normal. " and "Some phase error measurements do have weird glitches."
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73 Ludwig
Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804

 

Finally got a 14.074 mhz signal into the QMX+ at about 17 mv. My Rigol DS1102E scope may be insufficient for this task but I can display the 17 mv signal at the BNC? but nothing at pins 1 and 7 on either IC405 or 406. So my problem? is likely back towards the BNC...
--
73
Karl
KI4ZUQ
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

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Hi Guys!

I managed to install the 1_01_003 SSB Beta on the weekend and just took a few screenshots to provide another data-point for a High-Band QMX.
Calibration was ok, but 20m and 10m look a bit suspicious. I still need to build / adapt an external microphone.

All snapshots of my initial build and the SSB calibration on my Google drive:

If the link gets filtered out, i give you the 20m picture inline here:

10m looks similar

17, 15, 12, 11m more normal, as there is a dip with a clear minimum visible in the graph.

No idea if my results are good, bad, normal, abnormal. Just providing another set of measurements for you and Hans.

73 de Tobias DL3MHT
QMX SSB

 

First success yesterday with SSB on my QMX+ on 40m. Worked GB70RS at around 64 miles. He said the audio sounded good but to be careful of chewing the mic!
73
Tony
G3OVH
Re: QMX+ Initial Power Up Display Shows Only Boxes

 

Hi Don,
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I just finished my build of the QMX+. I have completed two other successful QMX builds.
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So, today I applied power as suggested and wound up with the square box display. I figured it was the interface between the display board and the main board. I got the iron hot and reflowed as many joints as I could. After eliminating 99% of the possible I went back to the inside top header. So looking straight on from the front, over the top edge, start counting from the left to the right and pin #5 is the one. After I got the solder to flow from the pin to the pad?? --->? new QMX+ is on the air.
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Hope that helps.
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73, Dean/ N2TNN
Re: Leaving 50-watt amplifier in-line but off

 

Hi Jim,
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I do not believe the PIN diodes have enough bias (reverse and forward) to allow the external transmitter to work.? It should be easy to install a relay that bypasses the amp altogether.
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73
Evan
AC9TU
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

Dear all.
on my QMX, Rev2, 80m-20m, the diagrams for the ‘phase error vs DAC’ do not correspond to Hans' example. I have performed a factory reset. I have adjusted the band configuration: start, end and centre. See screenshot. I have disabled ‘20/80 BPF TXswap’ in the menu.
I would be grateful if someone could post the band configuration for a QMX 80m-20m as an example in this forum.
Stephan, DD6DO
Updated Wiki Page: QMX QMX_plus SSB settings #wiki-notice

Group Notification
 

The wiki page QMX QMX_plus SSB settings has been updated by @Ludwig_DH8WN <DH8WN@...>.

Compare Revisions
Re: Can't get SWR sweeps to be 1:1 with dummy load

 

Back on the air :)
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I chose in the end to just replace ic 402 and 403, and everything seems to be working fine now.
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I'm still not sure what exactly killed the chips. The limiting diode and the receive switching fet seem to be functioning correctly, but it's certainly fixed for now.
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Thanks all!
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Greg,
N1TR?
Re: Qmx Single versus double click volume.

 

I actually removed the knob completely and it did not solve the issue.
so I have confirmed that there is no travel issues due to the ?knob restricting its ?movement.
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