Re: Output low-pass filters measurement with NanoVNA
#qdx
Andrey, the location you are injecting the signal into the filter is the middle of the filter and the filter is not even in the circuit unless the rig is on and 80 meters is selected, and if not transmitting, the other filters probably aren't turned "off" completely either. All this leads to bad VNA readings. If you want to test this 80 meter filter itself you will probably need to lift the cathode ends of D1 and D4 and connect the VNA leads to the two holes where these diode leads are removed from, and ground as well obviously. Good luck .. 73 ... Ron
Out of a NanoVNA Test board kit I connected a small adapter PCB that I can plug in LPFs and BPFs and test with a NanoVNA.? I also jury rigged a couple of connectors to 2 test cables that I plugged into the NanoVNA and the LPF, BPFs and they also tested OK with the NanoVNA.? So, if things are not looking good measuring the LPF in circuit, I would disconnect the coupling cap to the filter and tack solder in an input from the NanoVNA to the LPF eliminating impedance mismatches and test again knowing that only the LPF is what you are testing.
73 wt1v
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Re: Recommended DC Power Supply for QDX Transceiver?
I've been using PSUs for a while and have been very pleased. They come with two sets of DC screw terminals and the output voltage is adjustable - handy if your output voltage is controlled by the input voltage (that is, no volume pot between them) :-) As my setup is all 12V (nominal), the 12V units work out for me quite nicely. They're also cheap enough that I can afford to do stuff like devote a single PSU to that QRP Labs 50W amplifier that I should soon be using for FT8 (might only be a 3-6db wattage increase, but that can make a difference...), thus allowing all of the PSU's resources to be devoted just to the amplifier (as opposed to the transceiver + amplifier).
Regards,
Charles Johnson
KF4AYT
PS I'm typing this on my iPad and I can't seem to test the link above, but a Google search of 'Mean Well LRS' should do the trick if the above link doesn't work.
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Hi all,
?
Next monday, November 28th is the regular QCX Challenge, see all info on
?
If nothing comes in between, I will be QRV at 1300 and 1900, on 20m & 40m
?
73 es GL,
Luc ON7DQ
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Re: Output low-pass filters measurement with NanoVNA
#qdx
Out of a NanoVNA Test board kit I connected a small adapter PCB that I can plug in LPFs and BPFs and test with a NanoVNA.? I also jury rigged a couple of connectors to 2 test cables that I plugged into the NanoVNA and the LPF, BPFs and they also tested OK with the NanoVNA.? So, if things are not looking good measuring the LPF in circuit, I would disconnect the coupling cap to the filter and tack solder in an input from the NanoVNA to the LPF eliminating impedance mismatches and test again knowing that only the LPF is what you are testing.
73 wt1v
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Re: QDX firmware 1_06_004 beta
?re SPLIT es 'fox-s'
Lack of articulation on my part
????? the WSJT-X fox ; >(? I've??'never' been there
I should have said?
?? ...when the ((CW)) fox calls? "CQ UP 1...
Which implies he is running split
CW tip ...
A wise ole fox starts from the top of the pileup es works down
73 73
John
N3AAZ
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Re: QDX firmware 1_06_004 beta
On 24/11/2022 13:27, Cliff wrote: For Wsjtx, yet it isn't needed. Not all people live in FT8 land either. Cliff, Perhaps I should have asked Hans why he seemed reluctant to add split/extra VFO. I must be missing something. Or, why do you think it is necessary? 73 Alan G4ZFQ
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Re: QDX firmware 1_06_004 beta
Anyone using QDX on Top Band ?
72,
Bill, N4QA
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Re: QDX firmware 1_06_004 beta
Hans,
Your the Best!?
A nice surprise to explore for the QDX.
Thanks?
James
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Re: Recommended DC Power Supply for QDX Transceiver?
I have two of them, very reliable! It is 12V/30A (but small)? and will power my KX3/KXP100 (and QDX!!) no problem!
Also my QDX's are 9V builds and I use this:?Mini MP1584EN DC to DC buck converter. No issues with it - Search Amazon?Mini MP1584EN comes as a 6-pack for under $20.
73
Terry
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Re: #qdx no transmit on 80m 60m and 40m
#qdx
Hello Bernd
Please read operating manual section "5. Troubleshooting Transmit issues" at page 44 which describes this issue and its solution.?
On Thu, Nov 24, 2022 at 5:07 PM Bernd DL2NEA < dl2nea@...> wrote: Hi,
i build the QDX Rev4 for 9V. Only on the 40m, 60m, 80m bands at transmiting the current stays at the receiving level (about 130mA) and the LED blinks in the 2 times rythm. Antenna is a dummy load.
With the build in transmitting test when pressing 't' the current increases on all bands to about 1A.? FT8 operation on 20m Band was succesfully tested.
Any idea where to start troubleshooting ?
Bernd DL2NEA
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#qdx no transmit on 80m 60m and 40m
#qdx
Hi,
i build the QDX Rev4 for 9V. Only on the 40m, 60m, 80m bands at transmiting the current stays at the receiving level (about 130mA) and the LED blinks in the 2 times rythm. Antenna is a dummy load.
With the build in transmitting test when pressing 't' the current increases on all bands to about 1A.? FT8 operation on 20m Band was succesfully tested.
Any idea where to start troubleshooting ?
Bernd DL2NEA
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Re: QDX firmware 1_06_004 beta
Thank you very much Hans. I really appreciate it.?
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Show quoted text
Hello Cliff
> Any chance of enabling the Split and second VFO operations?
I am still far from convinced of the need for this, but I will enable it to keep the troops happy.? Hans,
Any chance of enabling the Split and second VFO operations?
Hi all
Here you can find a version 1_06_004 beta:
The version contains the following changes: - When bias mA is 5mA, disable PIN diode forward bias SMPS system completely (results in around 4mA default bias current).
- Change default 80m Frequency min to 3200000.
- Add "Night mode" parameter to configuration screen - when enabled, it makes panel LED very dim, by defining the GPIO pin with internal pullup to light the LED. It's dim but if the QDX is on a shelf in front of you and not in too bright lighting, it will be visible.
- Now successful TX is a 1Hz pulsating indication, the LED current actually follows a 1Hz sinewave; meanwhile the spacing between the 2 blinks in "audio insufficient" error reporting mode is now 0.2 seconds, wider spaced for easier counting
- Changed minimum TX freq from 300kHz to 75kHz (to allow 2200m operation). Note: receive quadrature for 2200m is not done yet.?
- Changed length of band name in the Band Config screen to 4 digits (to allow 2200m operation)
- Bug fix: Qn; CAT command return string length is now longer to fit larger numbers
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Re: QDX firmware 1_06_004 beta
Alan,
For Wsjtx, yet it isn't needed. Not all people live in FT8 land either.
73,
Cliff, AE5ZA
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Show quoted text
On Nov 24, 2022, at 06:07, Alan G4ZFQ <alan4alan@...> wrote:
On 24/11/2022 11:51, John Kirby wrote:
Split (mode THANKS) works very well when the fox calls "CQ UP 1" (1 kHz for example) John,
According to the manual WSJT-X has two ways of working split without the radio contributing. Basic no split changes the audio frequency, not always ideal, but "Fake it" tunes the radio.
73 Alan G4ZFQ
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Re: QDX firmware 1_06_004 beta
On 24/11/2022 11:51, John Kirby wrote: Split (mode THANKS) works very well when the fox calls? "CQ UP 1"? (1 kHz for example) John, According to the manual WSJT-X has two ways of working split without the radio contributing. Basic no split changes the audio frequency, not always ideal, but "Fake it" tunes the radio. 73 Alan G4ZFQ
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Re: QDX firmware 1_06_004 beta
?
Split (mode THANKS) works very well when the fox calls? "CQ UP 1"? (1 kHz for example) keeps the pileup off the fox so all hounds (troops :>) can hear the fox
72 73
John
N3AAZ
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Re: Recommended DC Power Supply for QDX Transceiver?
On 24/11/2022 08:58, Vojislav [YU4HAK] wrote: I use 12v from a running computer PSU molex (yes, the horror!) I am not horrified:-) I have used the PC supply for many years, I'm so used to it I forget and you reminded me. I use a simple LF iron-cored choke and capacitors as a filter, have never been aware of any problems. In fact for the older soundcard SDRs it helps to make ground loops easier to eliminate. And also 5 volts USB, a simple filter keeps it fairly quiet. Many good modern SDRs are USB powered. 73 Alan G4ZFQ
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Re: Recommended DC Power Supply for QDX Transceiver?
I use 12v from a running computer PSU molex (yes, the horror!) But it is actually not that noisy, barely noticeable on the waterfall. It is a high quality PSU though. I also tried a standard 12V 5A?adapter and that is ok too. A pack of old 18650 batteries is of course totally noise free, but if they are not new and high quality, voltage may drop once you start transmitting. My advice is no need to go crazy with fancy noise free adapters for QDX, as its filtering capabilities are amazing.
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Re: QDX firmware 1_06_004 beta
Hello Cliff
> Any chance of enabling the Split and second VFO operations?
I am still far from convinced of the need for this, but I will enable it to keep the troops happy.?
Hans,
Any chance of enabling the Split and second VFO operations?
Hi all
Here you can find a version 1_06_004 beta:
The version contains the following changes: - When bias mA is 5mA, disable PIN diode forward bias SMPS system completely (results in around 4mA default bias current).
- Change default 80m Frequency min to 3200000.
- Add "Night mode" parameter to configuration screen - when enabled, it makes panel LED very dim, by defining the GPIO pin with internal pullup to light the LED. It's dim but if the QDX is on a shelf in front of you and not in too bright lighting, it will be visible.
- Now successful TX is a 1Hz pulsating indication, the LED current actually follows a 1Hz sinewave; meanwhile the spacing between the 2 blinks in "audio insufficient" error reporting mode is now 0.2 seconds, wider spaced for easier counting
- Changed minimum TX freq from 300kHz to 75kHz (to allow 2200m operation). Note: receive quadrature for 2200m is not done yet.?
- Changed length of band name in the Band Config screen to 4 digits (to allow 2200m operation)
- Bug fix: Qn; CAT command return string length is now longer to fit larger numbers
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Re: QCX Mini Distorted tone at low volume
Hi Michael,
As others have suggested, I wrap 10 to 14 turns of coax through an FT240-31 toroid core (based on work done by K9YC) and I locate this choke approximately 0.05 wavelengths (on the lowest band) from the feedpoint of the EFHW (based on work done by AA5TB which I also confirmed via modeling).? Doing this does a great job keeping RF off the outside of the coax shield between the choke and the radio.? Also the outside of the shield between the feedpoint and the choke acts as an adequate counterpoise so you don't need to install an additional counterpoise wire.? The choke also helps reduce common mode noise that travels from your shack up to the feedpoint via the outside of the coax shield and this therefore often helps reduce your receive noise floor.? It also makes the SWR much more stable (repeatable) as it eliminates the outside of the shield between the choke and your radio from being another variable (additional counterpoise) that would otherwise alter the SWR depending on how it's coiled up, what its touching, etc.
73,
Don (wd8dsb)?
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Re: Low Output Power on 30M QCX Mini?
Hi Derek,
I built a 30 meter QCX Mini a few weeks ago and followed the procedures in the video that EI5EM provided you the link to.? I was able to get exactly 5.0 watts out using 12.0 Vdc and I measured the power output using my Oscilloscope across my 50 ohm load.? I too had to remove a couple of turns from L3, and I not only noticed a change in output power by changing the spacing on the turns, but also how close to the toroid core my winders were.? When winding the cores I actually push each winding tight to outside diameter of the core using my thumbnail when I'm winding the core, and also pull each turn of the wire taught to the inside of the core as I'm winding it, and I even noticed an improvement in output power when each end of the winding was pressed tight to the core on its way to the point where it gets soldered to the circuit board.
It really is an amazing radio, and I'm now going to start building one for 40 and then one for 20 meters.
Don (wd8dsb)
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Ronald Taylor
ON7DQ Luc
KB9NBL
Vojislav [YU4HAK]