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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

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

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

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

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

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

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

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

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

PS Steve KM9G of Temporarily Offline Ham Radio dives deep into toroidal tedium in THIS VIDEO. ( https://www.youtube.com/watch?v=0AJriYSinWc ) Apologies if this is not new info. Todd KE7AJZ --

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

On a similar note, here's a simple heat sink that should work well for any of these "finals clamped under a washer" resigns:??

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

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.

Trifilar not tricolor. Autocorrect is not electronic savvy.

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

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

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

I had a QDX with similar poor plots traced to an issue with the T401 equivalent

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