On Sat, Sep 28, 2024 at 01:13 PM, Hans Summers wrote:
I spent some time researching compression techniques and … CESSB. … SmartSDR software by Flex Radio Systems, Apache labs ANAN series and the Elecraft K4.
Hans, this is amazing news! I have a K4, and my experience with CESSB parallels your vision… The result is almost like having a linear amplifier — about 2 db virtual improvement for those hearing my signal. It has to be experienced to be believed.? 73, Randy K7RAN
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Re: Is there documented process to fully test QMX+ ?
Added info - We finished assembling the QMX+. ?When performing the ADC I/Q test we observe no I phase present on all bands(flat line). ?Q phase looks fine. ?Looking at the possible trouble shooting issues it would indicate faulty pre-amp or defective PCM1804. We do not currently have an oscilloscope available. ?We are wondering if it is a component we installed that may be the culprit. ?
Based on another thread, we rechecked the trifilar and tested for 2.7 volts on pin 1 and 7 on IC405 and IC406.?
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Thank you
Sam
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On Sat, Sep 28, 2024 at 08:08 AM, Peter HB9EBE wrote:
As far as I am concerned, I found Hans' update pretty complete, and would rather prefer that he can devote his energy to working on the next FW version rather than updating us. We know there are no show stoppers. Let's let him work!
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Peter HB9EBE
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Peter, had you prevailed, we wouldn’t have learned so much today.
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Re: QMX+ test ADC I/Q shows one phase missing
We also removed the trifilar and retested, then reinstalled.
Sam
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Re: QMX+ test ADC I/Q shows one phase missing
Hi Jeff -
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We finally got a chance to measure the voltage.? Yes, pins 1 and 7 does have 2.5 volts.? Not sure if you have any thoughts from here.??
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Thank you
Sam
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Re: Macbook Terminal Program - How to go back in QMX+ Terminal Menu
To enable Control-S and Control-Q enter
(you need Control-Q to exit menus):
stty -ixon -ixoff
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Pierre
VE3HQZ
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Re: #QMX Loaded FW 27, Now Dead?
#qmx
On Sun, Sep 29, 2024 at 03:46 AM, Todd Howell wrote:
In the meantime, any thoughts on the ADC voltages? Should those be 2.5v and 1.65v respectively?
Yes but there are some possible situation with the observed results, situation with wrong working SMPS. Maybe failures are inside the SMPS or between the SMPS and the controller
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E. g. Q108 doesn't switch on or L101 is broken but there is a low voltage at VCC coming from an other voltage rail across the circuits at the mainboard. This would show a to low VDD to the controller but not 0 Volt. The controller would increase duty cycle until the limit but without a result. This would fit to your observation
I'm going from memory but I want to say both ADC lines are in the 240mv range.
But ADC_3V3 around 240 mV doesn't fit to the screen shut from Diagnostics (3.50 V).
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So the two steps in my last post may bring more clarity.
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73 Ludwig
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I have been living this year for three months in a territory in a state of civil war - New Caledonia - with several total failures of internet and telephone. With my Hermes Lite 2 and my QDX Hi-band, the JS8 mode with JS8Call were my only "emergency" mean of communication with the world outside and with only 5 to 6 Watt output I could chat on bands from 40M to 10M with stations at nearly 10,000 miles. YES JS8 is an excellent mode even if it is not very much used. Note that I use only FT8 softwares to check the actual propagation as this FT8 mode is much more in use than JS8.
73 - Pierre - FK8IH
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Re: #QMX Rev4 v27, kit just built not working
#qmx
On Sun, Sep 29, 2024 at 12:48 AM, WV0H wrote:
Okay - I have the QMX transmitting now! I think there was a function set to disable the transmitter. (by default ????) but I toggled that setting in the terminal mode and now it transmits!!
Hello Myron, good news. Please tell which Parameter did you toggle? And this solved also the QMX freezing?
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73, Ludwig
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Exciting stuff, Hans.? Your updates are rabbit-holes into new worlds of knowledge HI. Thanks for them, and keep up the great work ;)
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HPE CU SN
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72/73 de Enzo M0KTZ
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Hans
What a magnificent introduction for your doctoral thesis?
72 73
John
N3AAZ
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Sweet update.?
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Im planning on buying 2 x QMX +.
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One build standard ,the other for experiments. Standard will be for digi modes and re learning CW . I appreciate the CW decode feature for backup!
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The experimental build ,I? may use the 10w PA for SSB,one of those N7DDC atu 100 tuners,Maybe In built in Battery etc. I will destroy something in the process ,but Its not a $2000 ic 705 (price in AUD $) so experiments are permitted!
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Just saving a few more pennies as I want to get everything in one go ,as I imagine postage to Australia will be a fair bit, if I were to break up the purchase into a few deliveries.
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Thanks. Brendan? ?VK2 QRM
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I know from time to time modes such as FT8 and JS8 rate a mention. I will take this opportunity to push at least one of these modes back to the front of mind.
The QRP Labs gear can already do WSPR and this mode is great, but for tracking a moving object the resolution is limited to a 4 digit grid square or with inherent risks the extend mode can be used to get 6 digits.
JS8call being more of a conversional mode offers a wide range of Directed and Undirected messaging, catching my eye is the ability to send grid squares with up to 10 characters? and have them appear in APRS. This is done over two 15 second messages rather than
the 4 minutes it takes in WSPR. I quite like this option as it levers off a well established and stable APRS network plus as the focus of APRS is the location of the object rather than the signal path it displays a bit cleaner on the maps
I realise HF APRS is doable, but transmit power requirements and lack of interest has prevented any new development in years. Whereas modes like WSPR have continued to see developments with a range of modern designs available for everything from a radio in
the shack to a balloon being accommodated. ?Given there is no need for two way messaging a product like the U3S would be ideal as it already has the GPS, Band Switching in a compact form, of course the QMX would also be a great platform (or maybe better) with
the higher transmit power.
Whilst not mention in the documentation for the APRSIS CMD usage, JS8call will not only pass APRS messages, but any correctly formatted "APRS" transmission which includes the Telemetry transmission.
73,
Warren, vk3byd
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Re: Is there documented process to fully test QMX+ ?
Up until the 21st century, radio manufacturers would include a theory of operation at the beginning of a service guide. Unfortunately, I am unfamiliar enough with the QMX circuit to even troubleshoot my own problems much less assist in this endeavor.?
I totally empathize with your situation and can only offer that we dig in and build something.?
Tomorrow, I plan on printing out the schematics and mapping out various points with voltage and resistance measurements. (The hope is to gain an idea as to why my PA is stuck in overload.)?
If someone did this with a working radio and published it, the value would be immeasurable and graciously welcome as a point of reference.?
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Thanks for your post Hans, your development of the QMX+ is awesome! My main transceiver is a Hermes Lite 2 but I built also a QDX Hi-Band and I'm mainly active on JS8 mode, realizing 10,000 miles QSO with only 5 Watt, I write real QSO, being able to freely and actively chat, not exchanges of reports like what is automatically done with FT8.
Well, if you need to have suggestions for another kit I would like to find a multiband Power Amplifier with the qualities of both your QCX 50 Watt monoband amplifier and your 10 W linear amplifier and with the necessary Low Pass Filters and some kind of Ultimate relay-switched LPF kit with components fit for the higher power, the switching could be automatically controled by the QMX+ as you already said there is plenty of spare memory in it.
About the power, as I wrote above 5 Watt already allows nice QSO but when I started building transmitters, in the 1960's? I remember I bought a beam tetrode ATS25 (military version of the 807) and I have kept it in my "museum" and at that time we were totally satisfied with 30 Watt output.
More simply I could just build a QMX+ and a QCX 50 W amplifier set on my prefered band (30 or 20M) and that would be a nice set for CW.
73 - Pierre - FK8IH
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Re: Macbook Terminal Program - How to go back in QMX+ Terminal Menu
Bill,
CTRL-A, then Q works on my Mac.
73 John M0JBA
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On 28 Sep 2024, at 23:04, William Hurley via < whurleyjr@...> wrote:
I have been able to successfully connect to my QMX+ using the native terminal program in Mac OS Sonoma. ?However, after selecting a sub menu item, I cannot go back to the main menu. ?I've tried CTRL-Q but nothing happens. ?My only option is to use Command-Q to log out completely and then log back in to the main menu. ?Do any of you Mac users know how to return to the previous menu item using the Mac terminal program?
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Thanks,
Bill K4GDR
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On Sat, Sep 28, 2024 at 09:13 PM, Hans Summers wrote:
One has to do *something* to establish the appropriate gain for the transmit chain from microphone to antenna. I do not feel that just having a manual gain setting and relying on the operator to speak in level tones at a fixed distance from the microphone, is really going to be a sufficiently "good" system. And since 5W of SSB is not exactly gigantic, it doesn't have the relative SNR advantages of narrow bandwidth modes like CW and many digi modes; so SSB needs all the help it can get. The key aim is to increase the average power level relative to the peaks, without causing clipping and splatter. There are several things that can take place in an SSB transceiver:
- Some kind of automatic gain control which is similar to what's done on receive
- Actual compression, in which quieter speech is amplified by a larger amount than loud parts of the speech
- ALC -? Automatic Level Control in which the PA itself acts to limit the amplitude to prevent clipping; in the case a quite sophisticated delay-line look-ahead system could be used.?
CESSB replaces the need for ALC and increases average power. Inevitably ALC will REDUCE the gain to an extent that SSB peaks don't cause clipping; effectively it increases dynamic range not decreases it so arguably it's the opposite of the compression we want.?
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Hans,
Just don't forget about audio equalizer..
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Just kidding! ;)
pz
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now it seems that QMX SSB performance will exceed what was possible with QSX. Which is a very interesting concept to put it mildly (actually I find it mind-blowing).?
Indeed. Nicely done Hans. I've been busy with Life Stuff these last few years and haven't been following as closely but I have a QMX+ kit sitting on the shelf waiting to be built. Perhaps its time to get building.
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I also want to say how much I appreciate the clarity of your writing. You've taken an enormously complex concept and made your audience feel smarter for understanding it. That's not easy to do.
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--
Ryan Flowers - W7RLF
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Re: #QMX Rev4 v27, kit just built not working
#qmx
Yes, I have run everything I can find in there.?
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On Sep 28, 2024, at 8:22?PM, Greg McCain via groups.io <gamccain50@...> wrote:
? Have you run the suite of diagnostics test available in a Terminal session??
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Greg
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Re: QMX+ build: so close, and yet....
Found my issue. Not enough enamel had been stripped off one the the single turn legs on the T501 xfmr. So check your T501 solder joints Michael!
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Randy K7RAN
Pierre Robillard VE3HQZ
Pierre - FK8IH
WV0H