Re: New kit: QDX - QRP Labs Digital Transceiver
I saw mention made of MFSK as a mode and I wonder how many realize MFSK can be used to send images. Yes, images!
I've been a fan of Kim Elliott's (KD9XB) program carried over shortwave, "Shortwave Radiogram"??Each week the program is carried by WRMI and WINB with 30 minutes of MFSK text and images. Here's a couple of examples of both great and so-so decodes I've received lately.
? ? ?
These were transmitted in MFSK64. The program usually alternates between MFSK32 and MFSK64. Other modes are demonstrated; Olivia is used from time to time.
It would be interesting to see the results from a QDX transmission!
--Al
WD4AH
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Re: QDX 80M getting 9W out?
My guess is that the MFJ is being ¡®a bit¡¯ generous.? The only way to be really sure is to measure with a scope or a known-calibrated (at the frequency of interest) meter. ? Mike WM4B ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Retired Doc
Sent: Monday, November 8, 2021 4:40 PM
To: [email protected]
Subject: [QRPLabs] QDX 80M getting 9W out? ? Just wondering if anyone else is getting 9W or thereabouts on 80M with 12.2V and drawing 970mA and I have the 3:2 windings.? That is way higher than the graph on page 4 of the manual.? After tuning it up I transmitted twice but then stopped b/c I was not sure if that was too much power??? I am reading my power forward on a MFJ 991E
On 20M and 40M I am getting almost 5W with 12.2V and drawing 670mA, I have made upwards of 15-20 Qs with those settings on those two bands.? I have not tried 30M yet.
I don't plan to use 80M until I know that much power is safe,
Thanks,
Kent KC9LIF
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Just wondering if anyone else is getting 9W or thereabouts on 80M with 12.2V and drawing 970mA and I have the 3:2 windings.? That is way higher than the graph on page 4 of the manual.? After tuning it up I transmitted twice but then stopped b/c I was not sure if that was too much power??? I am reading my power forward on a MFJ 991E
On 20M and 40M I am getting almost 5W with 12.2V and drawing 670mA, I have made upwards of 15-20 Qs with those settings on those two bands.? I have not tried 30M yet.
I don't plan to use 80M until I know that much power is safe,
Thanks,
Kent KC9LIF
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Re: receiver module questions
I have just finished building it inc. The polyphase module
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Now got to link all the bits together and test it
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Peter
M0PWX
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From: Karl-Heinz Pischke
Sent: 08 November 2021 19:09
To: [email protected]
Subject: Re: [QRPLabs] receiver module questions
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Hi Peter,
since I am interested in the receiver module (keyword: WSPR-"Transceiver"), I would be curious to see what you can report in terms of sensitivity. I would be happy about your message here.
Karl-Heinz, DL6MEE
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Suat,
The RF sweep is measuring the total response that includes the transmitter/receiver LPF.? I would contend that most, if not all are the measurement is the response of the LPF.? The bandpass aspect of the L12/T2 combination is wide, so not sure of the impact to the RF sweep report.? IF you want to make a change to the frequency response you would need to redo L2, L3, L4, L6, L8, and L10 toroids, though by the looks of your screenshots they look fine to me.? The 20 meters curve is different because it is tweaked to take into account the use of it on 30 meters.
Note:
L12 and the trifler wound T2 are part of the Reciever circuit and not used during transmit.? L14 and T1 are used only during Transmit. and do not impact the receiver.? They also are not very frequency dependant.? The 3 low pass filters are used on both receive and transmit, one at a time through the PIN diode switching network.
Above are my interpretations of the schematic and descriptions that I have access to.? They could be wrong and I am ALWAYS open to polite feedback and open discussion.? I am still learning.
73
Evan
AC9TU
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Yes, and the signal is injected through a 100k resistor (ok, well, it has a fraction of a pF parallel capacitance too ) so it will act as a "current source" when feeding the low-z antenna input. The injected voltage will be (almost) proportional to the impedance seen by the resistor and this can vary quite wildly if there is an antenna connected (instead of a known stable 50 ohm dummy load/termination).
73 SM6LKM
Alan G4ZFQ wrote:
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You will see different results but they will be wrong.
You must use a dummy load, any signals or noise received will give false readings.
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Re: On the TX signal, 5V tolerant I/Os and Pull-up resistors
Fred,
Fred,
At first, I did think that the TX line out of the STM32 was at fault and reported the symptoms in the other thread.? After Hans posted the way that the PTT actually works I went back and change to the Raspberry Pi and found that the TX line DID work.? So you were not incorrect, just not informed on the latest news on the other thread.
So I apologize for any confusion that I might have created.? In my defense, the total logic on how that line is set was not explained before.? It was after the explanation from Hans and the RPi test that I confirmed it was not an output pin failure.
Thank you for the suggestions.
73
Evan
AC9TU
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On 08/11/2021 18:36, Suat Alper Seyhan wrote: Instead of connecting a 50ohm dummy if I try it again connected to good/resonant antenna may I expect to see different results? You will see different results but they will be wrong. You must use a dummy load, any signals or noise received will give false readings. 73 Alan G4ZFQ
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Re: receiver module questions
Hi Peter,
since I am interested in the receiver module (keyword: WSPR-"Transceiver"), I would be curious to see what you can report in terms of sensitivity. I would be happy about your message here.
Karl-Heinz, DL6MEE
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Interestingly the tone seems to be much louder relative to the band noise when using headphones over a speaker. Perhaps the impedance of the audio device you have plugged in is effecting this? The radio is almost unusable when using headphones, but with a speaker I can barely tell a tone is there.
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I re-did the L12 quite carefully but pretty much nothing changed on the rf filter sweeps. Either I did the same mistake twice or there is something else going on. I was only looking to shape of the graph but when I now look in to numbers all the numbers are quite low compared to screenshots Hans shared. Instead of connecting a 50ohm dummy if I try it again connected to good/resonant antenna may I expect to see different results?
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Re: On the TX signal, 5V tolerant I/Os and Pull-up resistors
Well that's good news I guess.... I thought you said that the TX line from the processor was not functioning at all... I guess I misunderstood.
As bad as it potentially sounds for Hans, in reality we are just helping him improve the product.? ?I am starting to think these issues are not "permanent damage" type of issues, so they can be worked through.
I am glad it at least works with a RPi for you, though.? That's not a horrible limitation by any means.?
Now that you mention this... maybe Windows vs Linux needs to be mentioned with these issues from now on...? ?
Fred W0FMS?
On Mon, Nov 8, 2021, 10:50 AM Evan Hand < elhandjr@...> wrote: All,
Just as a reminder the TX signal on my QDX is working fine.? The issue was the secondary check that the MPU does for a valid tone to set and not a failure of the I/O output.? For some reason, my Windows PC does not get along with the QDX.? My Raspberry Pi 4 seems to work.
Now if I can just keep from shorting out the finals again, I can find out why the output is low.
73
Evan
AC9TU
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Re: New kit: QDX - QRP Labs Digital Transceiver
Regarding Olvia, I'm CQ'ing on 7.0714 dial (8/250), recorded it with another receiver, played the WAV in fldigi and it did decode! So I'll keep trying, see if I can make a QSO.
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See the last page in the manual ( Page 106 in current version)? All of Hans' manuals contain detailed revision status.
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Is it possible to get a summary of the revisions to the manual? I printed mine yesterday in anticipation of today¡¯s arrival and now see there¡¯s a revision posted today.?
Don
W6CZ
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Re: On the TX signal, 5V tolerant I/Os and Pull-up resistors
All,
Just as a reminder the TX signal on my QDX is working fine.? The issue was the secondary check that the MPU does for a valid tone to set and not a failure of the I/O output.? For some reason, my Windows PC does not get along with the QDX.? My Raspberry Pi 4 seems to work.
Now if I can just keep from shorting out the finals again, I can find out why the output is low.
73
Evan
AC9TU
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Bob,
Maybe try another PC if you have one.? As my posts in other threads have stated I am having issues with one of my Windows PC.? The Raspberry Pi seems to work fine.
The lack of current draw when in TX mode to me is an indication that the tone is not getting to the MPU.? Do you have the power setting in WSJT-X all the way up?? You cannot overdrive the audio, as it is only looking at the frequency.
73
Evan
AC9TU
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Thanks Evan
?? I put the QDX in its case. The USB cable has ferrites on both ends. I also coiled the excess length and tied it together.
For these tests I'm transmitting into a dummy load and using 9 volts power, so I only have 2.4 watts out (T1 is 3:2).
? I still saw the same behavior. Flashing led with power output on 40 and flashing led but no RF out on 20, 30 and 80 with no current draw on those bands above receive.
? My low band antenna is a lazy (drunken?) sorta vertical 57' long that runs from the remote tuner at the corner of my garage to the top of a nearby tree. There is a buried radial field of wires out to the edges of the yard. Since I use a remote tuner there is close to 1:1 on the coax leading in, but I also have several turns of coax through 6 FT240-43 torroids. There's also a box with relays that switch in a loading coil for 160 m so the antenna can be tuned easily and it disconnects and grounds the antenna when power is off.
? Good luck with your low power problem.
--
? 73
??? KD8CGH
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Re: Roots of Hans's supply chain issues
Love that movie!
Roy WA0YMH
Well, it?reminds me of my favourite "Snatch" movie line... "Never underestimate the predictability of stupidity".?
73 Hans G0UPL
On Mon, Nov 8, 2021 at 6:17 PM Mike Perry, WA4MP < editor@...> wrote:
> I don't think there's any great conspiracy or powerful forces directing it - but this is just the way the world system has been evolving. Thousands of individual decisions that make sense on a micro level, add up to make big consequences.
Quite right. I try not to ascribe to conspiracy anything that could be the result of stupidity. I once saw a cartoon that was all too apt. ¡°Be proud of your stupidity,¡± it said. ¡°It¡¯s what separates us from the animals."
For years I¡¯ve been warning Apple on Mac news sites not to do so much single sourcing, particularly in China. Always have several sources even if some cost more, I stressed. Recently, Apple announced that it would lose $8 billion dollars due to supply chain issues. I feel like I should bill them for business advice not taken.
And those California ports are jammed in part because the state¡¯s politicians stupidly passed a law that means that few trucks older than three years meet the pollution standards. Long-distance truckers, with more business than they can handle anyway, simply avoid trips into and out of the state. Politicians make one decision, thousands of truckers respond with another. No conspiracy. Just stupidity followed by a predictable and reasonable response. Truckers know trucking. Politicians do not.
¡ªMike Perry, WA4MP
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Re: Roots of Hans's supply chain issues
There's something like the 'law of unintended consequences'. You do one thing that makes sense and all sorts of things happen that you didn't expect.?
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73, Dan? NM3A
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Mike Besemer - WM4B
Retired Doc
Peter M0PWX
Fred Spinner
N3MNT
Bob Benedict, KD8CGH