A quality set of coil and pot trimming tools...


10-T4857

No connection, just a very satisfied customer..
73 Mike

Yesterday morning, idly running FT8 on my QMX when there was a CQ from New Caledonia, and ATNO for me.
The signal to noise was 0 to -5.? That's from half way round the world!? Tried calling but nothing so got the 7300 going and made the QSO, using about 90W. Cheating, I know but it was an ATNO.
The 7300 gave the S/N as -16 to -18.? Ran both at once in Rx and it was consistent, QMX -3 to -5, 7300 -17.? Similar antennas (EFHW and doublet side by side).

I'm not complaining but wondering why there should be such a difference, the 7300 is working nicely and this difference doesn't seem to be consistent,? I might try analysing the ALL.TXT files for the two systems to see if I can see what's happening.

Chris, G5CTH

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An even more simplistic view is that the audio signal is a single wiggly line, what you would see on an oscilloscope.? The subtle changes in that generate the multiple tones of speech, even those of a full orchestra.

What seems to be planned is to make changes to the frequency and amplitude of the RF signal to replicate that, with the appropriate modulation.? If you were doing AM all that would be needed would be to change the amplitude. For a 3 kHz bandwidth at least 6000 times a second.? For FM changing the frequency, also 6000 times a second.? SSB needs changing both.?? The challenge may be to synchronise the frequency and amplitude changes so they happen at the same time.

Chris, G5CTH

On 02/09/2023 02:46, W7QJQ wrote:

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 .

Sid,

Yes, the problem was not addressed, going into long term stability and frequency steps.
I put my Progrock to one side, I did not think I had it good enough for a HF RX or TX reference. I used a different technique and forgot the Progrock.

I only think HF. Roger is looking for a Pluto reference, that goes into the GHz range.

73 Alan G4ZFQ

As I see it, the main limitation, once you have the computing power, is the lack of linear amplification. If you had a linear amp, you would simply generate the IQ data and amplify it.?

I may have a simplistic view, and I hope to be corrected, but it seems to me that an EER method can only reproduce a single tone at a time. The code tracks the loudest frequency and duplicates. The wave shaping circuit changes the volume. ?This can not generate a true two tone signal.?
--
Colin - K6JTH?

Are there any experiences or thoughts regarding the blue vs. yellow displays? Does the blue appear less bright to the eyes? Any opinions regarding readability with old eyes? *(They both look pretty readable in the photos and videos, compared to my (tr)uSDX!

I'm about to place my QMX kit order and I've been contemplating the two display options.

Thanks and 73,
Cal -- AD8Q

A big, big thank you to Hans for a very enjoyable QDX build. Assembly and operations manual were clear and I had no problems with the assembly. QDX worked when first powered. I have made FT8 contacts on all the bands except 80M and 60M since I don't have an antenna for them. CAT control works flawlessly. What a really neat product!
Thanks Hans,
Rob, KF0BFA?

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

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?

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

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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

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.

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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.

PS Steve KM9G of Temporarily Offline Ham Radio dives deep into toroidal tedium in
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 mentioned.

73 Kees K5BCQ