Re: Using .33mm/AWG#28 for everything in the QMX+?

#130436

I recently finished a qdx and did this as well. All good. Good results.?

Re: Using .33mm/AWG#28 for everything in the QMX+?

#130435

Mine was recently completed and tested. Used .33 wire exclusively and everything works great.

--

Wayne S.
KF7RCM

Question about bands for "50W Amp for QCX-series"

#130434

What is the? highest? frequency for the 50 watt amp ?

?

When the 50 watt amp came to market it was when the QCX was out.

I have built the QCX and the documentation says it can do "single band, 160, 80, 60, 40, 30, 20 or 17m"

?

Since then Hans has come out with the QMX - of which I have built both the high and low band version.

?

I have recently finished the 50 watt amp.? The lowpass filter section matched the needs of the QCX.

I have been using the amp with my low band QMX.

?

My question :? Can I use my 10meter QMX with appropriate lowpass filter with the 50 watt amp.

?

Can someone explain what is the limiting factor?

?

I very much appreciate Hans'? qrp-labs.com? I have learned a lot.

?

stan? (ag5vh)

?

QMX mid band build - Continuity between A and B points

#130433

Hello fellow hams,

?

I started my QMX build today. I followed all the steps and I did all the checks mentioned in the instructions.

Also checked every solder joint before proceeding to the next one.

?

After building, checking and soldering T501, I checked the continuity between the A and B points as per manual.. and there is continuity.

?

Any advice on how to troubleshoot? Any probable suspects?

?

Thank you!

?

Pedro F4JAW

Re: QMX+ Low Image rejection at 160m,

#130432

Hello Trevor

If you look closely at it with some optical magnification you'll see that there already are thermals. And they're on all layers. Just that with 6 layers and thermals every 90° that means up to 24 thermals per ground point.?

73 Hans G0UPL

On Thu, Sep 26, 2024, 16:42 Trevor Shackleton via <trevorshackleton=[email protected]> wrote:

Show quoted text

Thanks Hans,

Great kit with excellent support. I look forward to the firmware updates in due course, appreciating that they take time to develop and test.

As an aside I do wonder if you considered adding thermal reliefs on the ground plane connections (on all layers). From experience they make reliable soldering (and a better chance of successful rework) much easier. I would have thought that the tiny increase in inductance would be insignificant at HF.

73 Trevor G6PSZ

Re: QMX+ build: so close, and yet....

#130431

I'm pretty sure I did add that jumper....but that doesn't mean it's right :-D I will check it!

Show quoted text

On Thu, Sep 26, 2024, at 10:37, Greg McCain via groups.io wrote:

I think Ian was asking about the jumper wire on the main PCB that has to be installed to get the RF signals in and out of the BNC connector.

It's described in the assembly manual on the same page as the 'Wind and install transformer T501' instructions.?

Greg

Re: Production seems to have slowed significantly

#130430

Thanks for the reply Hans.

I just really hope I get it before the snow hits, and in Canada that could be tomorrow for all we know hehe.

Damn labour laws .. Can you tell all employees all hands on deck until I get my order shipped, and also stop innovating until then ?

I never take leave(unless forced), because when I come back there's just too much work waiting for me, and I've forgotten how things work (Kind of like a vacation hangover).

?

These were my observations.?

The average change of my position between August 7 - August 28 (21 days) was ~ 14 per day
The average change of my position between September 6 - September 26 (20 days) is ~ 7.27?
That's close half of August's output so far...

Re: QMX+ build: so close, and yet....

#130429

I think Ian was asking about the jumper wire on the main PCB that has to be installed to get the RF signals in and out of the BNC connector.

It's described in the assembly manual on the same page as the 'Wind and install transformer T501' instructions.?

Greg

Re: Still no output on QMX

#130428

Re: Using .33mm/AWG#28 for everything in the QMX+?

#130426

I’m taking Hans at his word that “… we'll switch to 0.33mm for everything.“ Even though the photo in the assembly manual shows the thicker wire used for the single turn in T507, I used the same 0.33 mm and assembly was easier.?

I am at the point of switching tips and temperature to work on the back panel connectors, so I have a while to go before I can apply power and see how well my build works. It sure looks neater than my last one!

?

Joe KA1ZNA

Re: QMX+ build: so close, and yet....

#130425

I'm afraid I must say that I don't know yet! I was only using a dummy load, in my basement. I don't have an actual shack in my house -- I'm all portable, all the time -- and I reached this particular juncture at 2300 local time! :-D

It's a good question, though, and another thread to pull on. I will see if I can make time this evening to actually get an antenna up and see what/if I can hear.

Show quoted text

On Thu, Sep 26, 2024, at 09:11, Ian G4GIR wrote:

Michael,
?
Is it receiving? If not is the link fitted at the Aerial socket?
If all bands exhibit no output and all sweeps are up the swanny.
My guess is CLK2 is missing.
?
I had the same problem.
?
73
?
Ian G4GIR
?
----- Original Message -----
From: Michael - WD0OM via groups.io <wd0om@...>
Reply-To: <[email protected]>
To: <[email protected]>
Sent: 26/09/2024 05:14:04
Subject: [QRPLabs] QMX+ build: so close, and yet....

First, the good news: IT'S ALIVE.

It accepts power, it does not catch fire, and all the controls work and pass diagnostics.

The bad news: it does not pass transmit diagnostics, and all the different sweeps are wrong.

Attached is a (mercifully short) recording of the diagnostics screen including transmission into a dummy load.?

The most obvious problem is: wattage is 0!?

I'm using a buck-boost that's got the voltage at 12 (this is a 12-volt build). Idle draw is 0.115A. Draw when attempting to transmit during the diagnostic is 0.255, which seems low.

Obviously, some kind of rework will be necessary. What's my most likely culprit to start with?

Thank you all!

Michael WD0OM

Re: QMX+ build: so close, and yet....

#130424

开云体育

Michael,

?

Is it receiving? If not is the link fitted at the Aerial socket?

If all bands exhibit no output and all sweeps are up the swanny.

My guess is CLK2 is missing.

?

I had the same problem.

?

73

?

Ian G4GIR

?

Show quoted text

----- Original Message -----

From: Michael - WD0OM via groups.io <wd0om@...>

Reply-To: <[email protected]>

To: <[email protected]>

Sent: 26/09/2024 05:14:04

Subject: [QRPLabs] QMX+ build: so close, and yet....

First, the good news: IT'S ALIVE.

It accepts power, it does not catch fire, and all the controls work and pass diagnostics.

The bad news: it does not pass transmit diagnostics, and all the different sweeps are wrong.

Attached is a (mercifully short) recording of the diagnostics screen including transmission into a dummy load.?

The most obvious problem is: wattage is 0!?

I'm using a buck-boost that's got the voltage at 12 (this is a 12-volt build). Idle draw is 0.115A. Draw when attempting to transmit during the diagnostic is 0.255, which seems low.

Obviously, some kind of rework will be necessary. What's my most likely culprit to start with?

Thank you all!

Michael WD0OM

Re: QMX+ build: so close, and yet....

#130423

Jeff,

I have no doubts at all about that last part. Anything not working here is on me and my relative noviceness! The kit is great and the instructions (mostly) very clear!

T501 And L502 make sense as starting points. Thank you. Just needed a thread to start pulling on.

Michael WD0OM

Show quoted text

On Thu, Sep 26, 2024, at 05:45, Jeffrey W Moore via groups.io wrote:

Hi Michael,
?
that’s great that it is alive. ?Congratulations on that part.
?
look at all of your soldered joints under magnification and a bright light. ?Look especially at T501, the output transformer. ?If you didn’t scrape the enamel off the wire and solder those well it would exhibit this problem. ?The same for L502. ?Remember that the rig will work correctly if all parts are in the right place and soldered well. ?It’s rare that a part is defective.?
good luck
?
--
73
Jeff Moore
W1NC

Re: QMX+ Low Image rejection at 160m,

#130422

Thanks Hans,

Great kit with excellent support. I look forward to the firmware updates in due course, appreciating that they take time to develop and test.

As an aside I do wonder if you considered adding thermal reliefs on the ground plane connections (on all layers). From experience they make reliable soldering (and a better chance of successful rework) much easier. I would have thought that the tiny increase in inductance would be insignificant at HF.

73 Trevor G6PSZ

Re: 50w PA oscillations

#130421

Hi,

what is the PTT +5V line voltage when active? Does the red LED lights up bright?

I had to lower the value of the R210?in the QMX+ (just added 100R in parallel) to stabilize the PA RX/TX switching.

--

73 Bojan S53DZ

Re: QMX+ Low Image rejection at 160m,

#130420

Hello Trevor

160m image rejection is a known issue and I will fix it as soon as I have done the SSB firmware update. It's not a hardware issue, it's firmware. If all the other bands are correct then you don't need to worry!

73 Hans G0UPL

On Thu, Sep 26, 2024 at 3:12?PM Trevor Shackleton via <trevorshackleton=[email protected]> wrote:

Show quoted text

Hello,

My newly built QMX+ is showing poor image rejection in the test suite, but only when for 160m, other bands look OK.

The image at 160m indicated -3.7, with both wanted and image around -16.

Looking at the Test ADC I/Q, the two signals show almost in phase when they should be 90deg apart for quadrature (other bands show quadrature as expected). The Q waveform is?

only about half the amplitude of the I waveform (again only on 160m, other bands having equal amplitude as expected).

I suspect both the above are different views of the same issue, but I am not sure where to look to further investigate the cause.

Any suggestions appreciated.

Best regards Trevor G6PSZ

?

QMX+ Low Image rejection at 160m,

#130419

Hello,

My newly built QMX+ is showing poor image rejection in the test suite, but only when for 160m, other bands look OK.

The image at 160m indicated -3.7, with both wanted and image around -16.

Looking at the Test ADC I/Q, the two signals show almost in phase when they should be 90deg apart for quadrature (other bands show quadrature as expected). The Q waveform is?

only about half the amplitude of the I waveform (again only on 160m, other bands having equal amplitude as expected).

I suspect both the above are different views of the same issue, but I am not sure where to look to further investigate the cause.

Any suggestions appreciated.

Best regards Trevor G6PSZ

?

Re: To update??

#130418

Hi Jim
Please check Firmware version history from

you have to check yourself
73 DE muhsin TA1MHS

Re: 50w PA oscillations

#130417

Hi,

I have the QMX+ connected to the RF input of PA and the PA RF output is connected to dummy load.

QMX+ & PA is powered up.?

When QMX+ goes into transmit severe oscillations occur at junction of D3, D5, R8 (something like 10v RMS here)

The QMX+ is in practice mode so no RF out. Also?+5v PTT on ring is configured in the band setup (80m)

I was under the impression that no PTT mod is required on the QMX+??

Best Regards

Jonas

Den tis 24 sep. 2024 kl 10:45 skrev Bruce Akhurst via <bruce=[email protected]>:

Show quoted text

You’re going to have to be clearer about your set up?

?

if you’re saying an unpowered or powered 50WPA connected to the QMX+ makes it oscillate (in TX) when an antenna doesn’t the first thing to check (with a VNA) is the amp input impedance

But then you say nothing on RF in it RF out (do you mean it’s oscillating when PTT active and otherwise disconnected (not entirely surprising - Put a 3dB attenuator on the open input)

Please set out the exact layout and conditions that trigger your problem?

Re: Still no output on QMX

#130416

On Thu, Sep 26, 2024 at 05:59 AM, James wrote:

Do you have an idea why there's very little output om 60M-30M and too much on 20M & 17M?

?

Also the swr on the diagnostic screen is higher than what my SWR/Power meter says. Like I mentioned before, my dummy load measures 49.7 OHMS.?

?

James, there are more than one possible reason for the shown values (e.g. T507, LPF section, cables, dummy load). It would be helpful to have some additional values. Could you show for each band:

for RX - supply voltage and current

for TX into dummy - supply voltage and current, from Diagnostics screen PA voltage, output and SWR, from SWR/Power meter output and SWR

?

Could you show some pictures,

for T507 one from each end and one from the bottom side of the PCB,
for T501 one from each end,
the whole setup with QMX SWR/Power meter and dummy and
the dummy?

?

After the QMX gets warm, I can no longer power it down unless I unplug it. Do I also have a power supply problem?

Maybe.

?

Sometimes the only way to turn it on is by shorting Q104 on the power supply board.

This points in the same direction.

?

UpDate---Display is now working.?

How did you bring it to work?

?

Am I mistaken, I think I was told that the SMPS status is only supposed to turn on when you press the "T" ?while running the diagnostics and should stay off when pressing the "P" key.?

If you mean the BIAS SMPS it should be ON for "P" and "T".

?

73 Ludwig

?