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Re: QMX and SSB -- how?

 

The STM32F446 microcontroller has two 12 bit DACs. A DAC output is used to control the amplitude of the transmitter output; it's not done with PWM. The current firmware only uses that to control the rise and fall times of CW transmissions.

The uSDX already?does SSB using this method. The QMX should be able to do a much better job of it: more powerful?microcontroller and finer control over the signal amplitude. (The uSDX uses PWM for that.) We will have to wait and see whether it will be good enough to satisfy Hans.

On Fri, Sep 1, 2023 at 10:33?PM Stephan Ahonen KE0WVA <stephan.ahonen@...> wrote:
It's pretty intuitive if you think about what an FM signal looks like in IQ representation, and what an AM signal looks like in IQ representation. You can take any signal in IQ space and determine its FM component and its AM component. The QMX can rapidly retune its oscillator thousands of times a second, and it can PWM the transistor feeding the PA, to recreate the FM and AM components respectively. This will be pretty kickass if it can be pulled off with this hardware.

Re: QDX - protection of BS17O PA

 

Thanks all for your comments. I decided to solder a 1N4148 diode in parallel to L14.
Additionnally I always tune my EFHW antenna with a transmatch fed by a NanoVNA until it's perfectly tuned.

And to be sure I missed nothing I ordered with my QDX kit a lot of 10 BS170!
73 - Pierre - FK8IH
Re: Dire need of a part

 

Dear Karl,
You can add my name to that pool of "lifetime supplies"? I pretty much have them and don't mind sharing.? Pretty soon I will have 200 0805 47jH inductors to add to the Millons of parts I have

Take care and have fun,
73 Dave WA5DJJ?
Re: FT8 for U3?

 

Hi Jim,

Yes. I am using a simple command line in Linux on a RaspberryPi 3+ to sent individual FT8 (and WSPR) messages. I'm not using WSJT-X for this application, so no pull down menu.

-Bob? KA5MIZ

On Friday, September 1, 2023 at 10:09:53 PM CDT, Jim Cooper <jtalert@...> wrote:


On 2 Sep 2023 at 2:53, Robert Rabin wrote:

> However, I suspect that the messages
>? could be ambiguous and conflict with those from existing balloon
>? transmissions. For this reason, I've considered FT8 instead.

are you aware that even the 'custom' data field
in FT8 can contain NO MORE than 13 characters,
including any space characters?

and generally such custom data fields are
entered manually and manually selected from
a drop-down menu if there are more than one
FIXED data fields.

Have you read the WSJT-X User Guide ?

w2jc






Re: FT8 for U3?

 

On 2 Sep 2023 at 2:53, Robert Rabin wrote:

However, I suspect that the messages
could be ambiguous and conflict with those from existing balloon
transmissions. For this reason, I've considered FT8 instead.
are you aware that even the 'custom' data field
in FT8 can contain NO MORE than 13 characters,
including any space characters?

and generally such custom data fields are
entered manually and manually selected from
a drop-down menu if there are more than one
FIXED data fields.

Have you read the WSJT-X User Guide ?

w2jc
Re: FT8 for U3?

 

I've been interested in including observations from a weather station (such as air temperature, humidity and air pressure) in the WSPR message as is done with high altitude balloons. I've considered encoding the weather observations using a scheme similar to what is described in the link below. However, I suspect that the messages could be ambiguous and conflict with those from existing balloon transmissions. For this reason, I've considered FT8 instead.
??




On Friday, September 1, 2023 at 08:23:28 PM CDT, KK4ITX John via groups.io <jleahy00@...> wrote:


As a BIG fan of WSPR for such efforts I can’t imagine why you wouldn’t use it? I could even help on the US side on some schedule, IMO WSPR is the very best mode for this.

John?
KK4ITX?
Florida?

?Each mistake is a learning opportunity.?

On Sep 1, 2023, at 12:25 PM, Nigel ZS6RN <zs6rn@...> wrote:

?No stress Hans, 100% understood re your todo list ?
73

Re: GPS disciplined oscillator.

 

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I did extensive testing of the ProgRock2? reporting the results and starting a thread
?ProgRock2 as a GPSDO and an anomaly
?in message #101344.? I saw essentially the same thing that did Alan G4ZFQ .

The attached jpg shows the set-up.? The video can be seen at
?

73, Sid? W7QJQ
Radio Welling


Virus-free.
Re: QMX and SSB -- how?

 

It's pretty intuitive if you think about what an FM signal looks like in IQ representation, and what an AM signal looks like in IQ representation. You can take any signal in IQ space and determine its FM component and its AM component. The QMX can rapidly retune its oscillator thousands of times a second, and it can PWM the transistor feeding the PA, to recreate the FM and AM components respectively. This will be pretty kickass if it can be pulled off with this hardware.
Re: FT8 for U3?

 

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As a BIG fan of WSPR for such efforts I can’t imagine why you wouldn’t use it? I could even help on the US side on some schedule, IMO WSPR is the very best mode for this.

John?
KK4ITX?
Florida?

?Each mistake is a learning opportunity.?

On Sep 1, 2023, at 12:25 PM, Nigel ZS6RN <zs6rn@...> wrote:

?No stress Hans, 100% understood re your todo list ?
73

Re: QCX mini 40M T1 winding #qcxmini #t1 #40m

 

PS Steve KM9G of Temporarily Offline Ham Radio dives deep into toroidal tedium in
Apologies if this is not new info.?
Todd KE7AJZ


--
?
?
Re: QDX - protection of BS17O PA

 

Ted,

Looks good as long as there are no shorts and you still use the "washer and nut" to force the flat sides of the BS170s to make good thermal contact.

73 Kees K5BCQ
Re: QDX - protection of BS17O PA

Ted
 

On a similar note, here's a simple heat sink that should work well for any of these "finals clamped under a washer" resigns:??
Re: QMX pre-assembly USB-C question

 

Excellent, Brian. That is exactly what I was talking about. Especially use liquid flux to improve the solder surface tension "wicking" between the 16 pins and the 16 via barrels as Tisha mentioned.

73 Kees K5BCQ
Re: #QMX #BPF problems with fault finding #qmx #bpf

 

I wound the Trifilar using tricolors to make it easier and not having to use an ohm meter:)

A lot of left over wire from Elecraft kit building.
Re: #QMX #BPF problems with fault finding #qmx #bpf

 

Trifilar not tricolor. Autocorrect is not electronic savvy.
Re: #QMX #BPF problems with fault finding #qmx #bpf

 

C406 is a quick way to check the tricolor windings. If it’s not 2.5v then likely the tricolor (maybe an IC but less likely). If it’s good then the tricolor may still be bad and that’s when I rewind it just to be sure.

-Mike/w1mt
Re: Dire need of a part

 

This may be a good time to suggest we pool our "lifetime supplies" of various parts especially the small and smaller SMD parts that can sneak off with one stamp!
--
73
Karl
KI4ZUQ
Re: #QMX #BPF problems with fault finding #qmx #bpf

 

I have a similar problem Marek, TX is OK but in my case no receive at all, and all the graphs flat line.
I'll? be watching this space with interest.

Paul DJ0CU G4ADF
Re: #QMX #BPF problems with fault finding #qmx #bpf

 

I had a QDX with similar poor plots traced to an issue with the T401 equivalent?
Re: QDX - protection of BS17O PA

 

QCX mini has a class E pa different than QDX which has class D PA with two sets of bs170s. In qcx mini one 1N4756 zener diode will do the job. In qdx we need two of them.

73

Barb WB2CBA
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