Hi Will
I also found this article on the ARRL website. It is bit beyond my ability but the group might find it insightful.
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The article is about Controlled Envelope SSB (CESSB). It's a different topic to the EER method of SSB modulation.?
But on the CESSB topic, the article is *THE* definitive article describing what CESSB is and why it's important. But note also that for QMX I developed a completely different way of achieving CESSB which has slightly higher performance and other significant advantages.?
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I also found this article on the ARRL website. It is bit beyond my ability but the group might find it insightful.
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Re: How to pre-order/order a QRP Labs QMX+
Hi Pete
QMX+ stock in the website was incorrectly at zero because I had failed to adjust it for the recent new batch of 1000 new QMX+ kits. I've updated it. So you can order now.?
73 Hans G0UPL
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Is there a procedure to pre-order a QMX+ that is no longer available in stock?
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If so, where might I find instructions to do so?
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Pete/wa4hei
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Re: 43pF capacitor missing
Reinhard, I think you need C522. It's important for harmonic supression.
Please check if C522 is hidden somewhere. I read about a part was hidden in the hole of a rotary knob.
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If it's realy not in the bag you may ask QRP Labs.
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73 Ludwig
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Re: QMX and SSB, will it work with MFSK?
Describing the signal from a microphone as baseband SSB is an interesting take.
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Synthesizing SSB amplitude and frequency/phase from baseband audio is different than EER implementations of the past.
How about "SEER", for Synthesized Envelope Elimination and Restoration?
A look into the future of SSB transmission.
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Jerry, KE7ER
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On Mon, Jan 27, 2025 at 09:01 AM, Hans Summers wrote:
It's different but not as substantially so as may appear at first sight. You can easily consider the signal coming from the microphone to be baseband SSB. When that is run through a Hilbert Transform, resulting in I and Q signals; taking the arctan of I / Q gives the phase angle and the magnitude of I and Q is given by sqrt (I^2 + Q^2). You could quite easily consider that the baseband SSB is being stripped into phase and amplitude information. Mixing up to the operating frequency, is done by using the '5351 and application of phase shifts at each sample, by frequency offsets. I'm not sure that the implementation difference is sufficient to warrant a new name ;-)? "EER" is fine by me!
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Thanks Paul,
now I've found your test points.
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l (BS170 gate) is ok.
m (BS170 drain) is wrong. It's because the PA voltage is nearly 0.
j (PA voltage before L502) is nearly 0 V but should be 1 or 2 V below the supply voltage.
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The same question like Stan wrote before. Is your QMX in Practice mode oder did protection kick in? If not, something may be wrong around the solder joint to L502 (point j) (like Stan wrote before) or around Q507. Please check voltage at S, G and D of Q507. It should be
- at source around supply voltage,
- at gate around 2 V below source and
- at drain around 1 or 2 V below source.
BTW how did you start transmitting?
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73 Ludwig
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Re: QMX 60-15M won't turn on... potential solution
Don's method works well. Here is another option. I use miniature test hooks - see exampleattached. I do NOT hook them or remove them from a live circuit. I power down, then hook up to whatever measurement point I am interested in, then power back up to do measurements. Before removing or moving them, I power down again.?
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73, Dan? NM3A
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https://www.amazon.com/dp/B09TPBS7YF/ref=sspa_mw_detail_0?ie=UTF8&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams
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Static wrist strap. You'll need to throw a lot of heat, quickly,? into component leads that go to ground. I always recommend stripping toroid wire leads using the 'solder blob drag method' before soldering to the PCB.?
Follow the assembly manual closely. Though, you might want to dig up the instructions for the slightly different assembly steps for the LCD display. I used that suggestion since it made good sense. Made it much better aligned and easier to get the pins well soldered without possible bridges?
GREG
On Mon, Jan 27, 2025 at 10:29 AM, Paul Harker via groups.io <Paul.r.harker@...> wrote: My QMX¡Á kit arrived today, and I'm almost ready to go. Other than brewing a fresh pot of coffee, are there any tips or hints regarding this particular kit?
?
?
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Re: How to pre-order/order a QRP Labs QMX+
Basically you order a QMX+ and then select assembled rather than kit. ?There will be a few months wait, though, as they have a long list of assembled gear orders. ?It takes some time!
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Show quoted text
On Jan 27, 2025, at 9:18?AM, Fred Murray <fredmurray919@...> wrote:
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Is there a procedure to pre-order a QMX+ that is no longer available in stock?
?
If so, where might I find instructions to do so?
?
Pete/wa4hei
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Re: Almost random swr spikes
Both Pacific Antenna and Elecraft have nice QRP dummy loads. Both also have test points for measuring voltages with a DMM that can be plugged into a simple formula to show Watts Output.? Greg?
On Mon, Jan 27, 2025 at 10:00 AM, DH8WN@... <DH8WN@...> wrote: On Mon, Jan 27, 2025 at 02:37 AM, Nico Smith wrote:
I don't have a dummy load or an inline swr/watt meter.
Nico, when building a TX it's a good idea to use a dummy load for testing.
You may use something like the QRP Labs dummy. It's not only a dummy. Connecting a DMM to a special connection you are able to measure the rf power.
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73 Ludwig
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How to pre-order/order a QRP Labs QMX+
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Is there a procedure to pre-order a QMX+ that is no longer available in stock?
?
If so, where might I find instructions to do so?
?
Pete/wa4hei
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Re: Almost random swr spikes
Its always nice to have a bunch of 1 to 5w resistors around. Especially the old carbon ones. couple of 100ohm resistors in parrallel for 50ohm load. A bunch of 20 1000 ohmers in parrallel. Or even incandescent ( getting hard to find) headlamps and turn signal bulbs in par/ser configurations. Even a bath of salt water or carbon rods from batteries. The possibilities abound. Or just a dummy load off amazon ?
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Lots of good lighting and a magnifier. Be sure to scrape the magnet wire well. Take your time!
On Mon, Jan 27, 2025 at 10:29?AM Paul Harker via <Paul.r.harker= [email protected]> wrote: My QMX¡Á kit arrived today, and I'm almost ready to go. Other than brewing a fresh pot of coffee, are there any tips or hints regarding this particular kit?
?
?
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T501 is a big pain for me when I built mine.
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Many thanks for this post Stan.? I found it while searching for SWR and it seemed to feature exactly my problem.
I am unsure if all is now well but the SWR graph has gone down from a peak of 10 to about 2 as a result of re-soldering T501 which looks like a good start.
73,
Rod, M0JLA
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Dave and Paul,
Take your time! Be careful about static discharges, especially this time of year. Also scrape the wires of the toroids thoroughly before trying to solder them in place.
Have a bit wider solder tip for those ground points¡..it takes quite a bit of heat to get the solder flowing¡.6 layer board and Han¡¯s extensive ground planes. Many of the issues that people have had are due to poor soldering (I found it a humbling experience).
Read the assembly instructions carefully and take your time. As careful as I thought that I was, I stupidly soldered ALL of the controls on the front panel board on the WRONG side!!! Talk about depressing. I fortunately was able to undo this unnecessary mess. Moral to the story¡..DON¡¯T push it if you are tired or distracted
. The assembly is not rocket science snd I am certainly NOT a rocket scientist but I am definitely more humbled as a result.
Len KJ9E
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Re: QMX and SSB, will it work with MFSK?
Hi Jerry
> When saying that the QMX has a new method of SSB > modulation, we should acknowledge the history behind it.
Yes, correct. It isn't new (and I've never said it was new). As you said, Kahn's 1952 IEEE paper was the "new" proposal of EER (Envelope Elimination and Restoration". In amateur radio use the two examples I've studied (which aren't the whole list), are: - Polar Explorer, a 500W (if I recall) SSB transmitter described in a QEX 2017 article and which I saw demonstrated at Dayton Hamvention in 2018).
- uSDX / (tr)uSDX by Guido PE1NNZ (and many contributions from others) as you mentioned.
I think Guido PE1NNZ's uSDX code is the leading example that has popularized EER and is substantially as followed by QMX/QMX+. The implementation is in many ways quite similar but QMX has a highly linear amplitude modulator and much more powerful processor than uSDX, which is what delivers the much higher performance in QMX.?
> The approach Guido and Hans have taken is significantly > different than anything before. > The frequency and amplitude information are generated > mathematically, not stripped from a traditional SSB exciter. > Somebody will have to come up with a catchy name for this > since it is no longer Envelope Elimination and Restoration. ? It's different but not as substantially so as may appear at first sight. You can easily consider the signal coming from the microphone to be baseband SSB. When that is run through a Hilbert Transform, resulting in I and Q signals; taking the arctan of I / Q gives the phase angle and the magnitude of I and Q is given by sqrt (I^2 + Q^2). You could quite easily consider that the baseband SSB is being stripped into phase and amplitude information. Mixing up to the operating frequency, is done by using the '5351 and application of phase shifts at each sample, by frequency offsets. I'm not sure that the implementation difference is sufficient to warrant a new name ;-)? "EER" is fine by me!
73 Hans G0UPL
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Great photo: it looks like you have fun times in store!
Personally, I would stay away from the coffee: you want steady hands for that soldering iron!
Enjoy!
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Read AND re read the manual a few times and then watch all the videos by the gurus. ?You will still have questions but there are those out here to answer your questions. ?And remember the first instruction from my old experienced college professors: ?THERE ARE NO DUMB OR STUPID QUESTIONS! ?There are just those too timid or shy to ask.?
Having the courage to ask a pertinent question that others were too afraid to ask (even if it IS in the fine build instructions but you did not see it¡. You will on the next reading) is so important and if you don¡¯t ask you will never know.
Build on my friends. ?The best lessons I have to teach my younger or newer fellow hams I learned by mistakes and sometimes assisted by the smell of the magic smoke. Be the REASON someone smiles today.
Dave K8WPE
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Show quoted text
On Jan 27, 2025, at 10:29?AM, Paul Harker via groups.io <Paul.r.harker@...> wrote:
? My QMX¡Á kit arrived today, and I'm almost ready to go. Other than brewing a fresh pot of coffee, are there any tips or hints regarding this particular kit?
?
?
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Will Grocott M0LGW
Joe AI5DD
Todd W2TEF
David Wilcox K8WPE