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Re: Output vs. frequency behavior QCX 30m
开云体育If you are trying to operate on both 30/40, the answer is likely that the
output stage, which is a class E amplifier, needs to operate reasonably close to
its optimum resonant frequency.? The series tuned part of the circuit (C30
and L4) can’t be tuned to a “compromise” frequency without degrading one or the
other or both frequencies.? Although broad enough for a single band, it
just won’t work that well if you are away from the resonant frequency because
its efficiency depends on its switching point of the output fets occurring at
near zero current.? As soon as its resonant frequency is moves
significantly away from it’s optimum single band frequency, the three output
fets will experience much higher current at the switching point and end up
dissipating a lot of power, reducing the output power.?
-Steve K1RF
? From: VK5EEE
Sent: Wednesday, December 13, 2017 9:03 AM
Subject: Re: [QRPLabs] Output vs. frequency behavior QCX
30m ?
73
Enno, I too find the same as you. I don't know the answer. It sure works on both 30/40, which also is unexpected, after all I was trying to make mine work on 20/30 ! I would like to have higher power output but have not found the way to do it but I've not been trying very hard. I console myself that the difference is only maybe 1dB. A doubling of the power would only be 3dB. I'm pleased though that it works even better on 40m, which was surprising. However the little extra power on 40m, in practice, remember of course that on 30m any antenna is going to perform better generally for any given height, than on 40m, so in reality of on air practice, I think no disadvantage in the slightly less power on 30m, aside from the fact it is only around 1dB in my case, e.g. getting 2W instead of 3W, or 3W instead of 4W, depending on the voltage. So I'm happy with it. I'd like to find some cheap PA that would be a separate kit that would take power up to say 10W or so but could not find any such from searching eBay. |
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Re: DVM/RF detector header Question
I also seem to remember some other folks getting low RF output because a toroid underneath the LCD screen would contact one of the tabs holding the screen in place. ?I bent the mounting tab flat against the LCD board on mine. ?I would do it to yours too just to be safe.?
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R: Re: [QRPLabs] Boxing the QCX
Fabrizio Menghini
开云体育Good info. I bought it in UK, shipping time is short than Thailand. For EU country there are import tax+vat too from Thai (not for UK). Best regards Fabrizio Inviato dal mio dispositivo Samsung -------- Messaggio originale -------- Da: John Payne <payne0j@...> Data: 13/12/2017 15:51 (GMT+01:00) A: [email protected] Oggetto: Re: [QRPLabs] Boxing the QCX For what it's worth, Tayda has the Hammond 1590BB painted for
$6.99.?
No affiliation or pecuniary interest, just trying to help. W4CWZ On 12/12/2017 10:16 AM, Jonathan
Bresler wrote:
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Re: New Year's Eve Operation
Here's a comparison between two power supplies running FSKCW on my U3S (Single band, w/ 5W PA kit outputting 2W TPO). Top image is with a switching supply (Radio Shack 19A). Bottom image is with homebrew 3A linear supply with KD1JV's regulator circuit. (). Linear looks not as ragged with a lot less noise.
?Switcher PS:??? Linear PS:? ? ??? Cheers! --Al WD4AH |
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Re: Boxing the QCX
开云体育For what it's worth, Tayda has the Hammond 1590BB painted for
$6.99.?
No affiliation or pecuniary interest, just trying to help. W4CWZ On 12/12/2017 10:16 AM, Jonathan
Bresler wrote:
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R: Re: [QRPLabs] Boxing the QCX
Fabrizio Menghini
开云体育Martin thanks very much. 73 IZ0HCC Fabrizio Inviato dal mio dispositivo Samsung -------- Messaggio originale -------- Da: Martin Waller <martin@...> Data: 13/12/2017 13:34 (GMT+01:00) A: [email protected] Oggetto: Re: [QRPLabs] Boxing the QCX Hi Fabrizio, ? I’ll put together some images, notes, etc and share them on GitHub… I’ll let you know when it’s there. ? Martin ? From: [email protected] [mailto:[email protected]] On Behalf Of Fabrizio Menghini
Sent: 12 December 2017 19:33 To: [email protected] Subject: Re: [QRPLabs] Boxing the QCX ? Thanks Martin! ? I think the alu box needs 6-10 days for Italy delivery... ? Do you have the drlilling sheet for lcd and qcx pcb? ? Many thanks Martin. ? P.S.sorry for my basic and school level english...? ? Regards ? Fabrizio
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Re: Output vs. frequency behavior QCX 30m
I built mine for 30m and had similar low power issues. I took 2 turns off the LPF inductors and now I get 3.5W on 30m and 4.8W on 40m on a 13.8V supply. It was about 2W on 30m and 3W on 40m before.
I also suspect reducing the number of turns on L4 will even this out. I'll try this soon aim for 4W on both bands. The rx works very well on both bands though is peaked on 30m as per the 30m build instructions. Steve MW0KST Sent from my iPhone |
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Re: Output vs. frequency behavior QCX 30m
73 Enno,
I too find the same as you. I don't know the answer. It sure works on both 30/40, which also is unexpected, after all I was trying to make mine work on 20/30 ! I would like to have higher power output but have not found the way to do it but I've not been trying very hard. I console myself that the difference is only maybe 1dB. A doubling of the power would only be 3dB. I'm pleased though that it works even better on 40m, which was surprising. However the little extra power on 40m, in practice, remember of course that on 30m any antenna is going to perform better generally for any given height, than on 40m, so in reality of on air practice, I think no disadvantage in the slightly less power on 30m, aside from the fact it is only around 1dB in my case, e.g. getting 2W instead of 3W, or 3W instead of 4W, depending on the voltage. So I'm happy with it. I'd like to find some cheap PA that would be a separate kit that would take power up to say 10W or so but could not find any such from searching eBay. |
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Re: QCX CW TRANSCEIVER problem.
I hear this same sound when trying to listen above a certain frequency (from memory around 12 or 13 MHz) on my QCX which I built for 30m. It has something to do with the programming and quadrature -- Hans said he may fix that in a future update of the firmware. But not sure why you are experiencing it, and I'm sure that those who understand this issue would be able to reply and let you know what to do. A little surprised no one yet answered you here, so hope you get answers very soon.
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Re: Boxing the QCX
开云体育Hi Fabrizio, ? I’ll put together some images, notes, etc and share them on GitHub… I’ll let you know when it’s there. ? Martin ? From: [email protected] [mailto:[email protected]] On Behalf Of Fabrizio Menghini
Sent: 12 December 2017 19:33 To: [email protected] Subject: Re: [QRPLabs] Boxing the QCX ? Thanks Martin! ? I think the alu box needs 6-10 days for Italy delivery... ? Do you have the drlilling sheet for lcd and qcx pcb? ? Many thanks Martin. ? P.S.sorry for my basic and school level english...? ? Regards ? Fabrizio
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Re: Boxing the QCX
开云体育Many thanks Petr. ? Martin ? From: [email protected] [mailto:[email protected]] On Behalf Of Petr Ourednik ? Martin, it is definitely best housing I ever saw until now. Big big congrats for excellent job. I will probably copy it :) |
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Re: New Year's Eve Operation
Hi Daniel, Argo works fine under Wine. QRSS-VD is quite good but is a little more involved to get running. SpectrumLab works ok under Wine and is another good option to try. 73 Simon G0FCU. On 13 December 2017 at 12:24, Daniel Ekman SA2KNG <knegge@...> wrote:
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Re: New Year's Eve Operation
Planning to run my U3S on at least 30m FSKCW6 and WSPR, but got curious on the receiving stuff. I run Debian linux in my shack and have tested Baudline for qrss viewing. Almost everyone talks about Argo, but has anyone tried this under wine or is there better options for linux ? I've not had much luck with glfer as it uses OSS, and I haven't figured out how to make pulseaudio work with this yet. Any tips are welcome (: |
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Output vs. frequency behavior QCX 30m
Dear group,
I have built a QCX 30m (#1229). Building went straight forward. I could peak the input filter nicely with the trimmer in the mid position. However output power was a bit low: 2W with 13.6V after the diode. The LPF already had all toroids with 1 winding less than per manual. So I decided to remove one more winding. This did not had any effect at all ... ! Ian, G4GIR, noted me on the fact that a 30m QCX might as well work on 40m. It appeared the power output was 3W on 40m. The power actually almost linearly increases when decreasing the frequency. So I decided to rebuild the LPF on a separate piggyback PCB using high quality silver mica capacitors.   Toroids are wound with 0.4mm wire, 1 winding less than indicated in the manual. Caps are Cornell Dubilier silver mica (~�4 each ...). This resulted in a schoolbook filter behavior as measured with a miniVNA, see attached file. After building the piggyback PCB onto the QCX, I ended up with 3W output on 30m. That is a clear improvement. However, now I have also 1 W more on 40m => 4W out, so I still have some unexplained attenuation on 30m compared to 40m. Having ruled out the LPF now, does anyone have a clue what component could be responsible for this behavior ? I can only think of C29 or C30 (500V ceramic disc replacements are on the way). L4 is already rewound with 0.5mm wire so I really expect no issue there ... Are more builders seeing this behavior ? Any suggestions welcome. (P.S. you can easily QSY out of band by programming a preset with the desired frequency in menu 1.x, and then recall the preset and write it to the VFO) -- Regards/73, Enno, PF5X |
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Re: New Year's Eve Operation
Are you using as switched mode power supply, the logic in the U3S likes clean dc supply preferably from an analogue supply.?? Just my observations.? Cheers and 73.
On Tuesday, 12 December 2017, 13:18:57 GMT, Al Holt <grovekid2@...> wrote:
David, Thanks for your tips on setting QRSS up on the U3S! I've got mine going on 30m and over the last couple of days have been trying one FSKCW transmission after a WSPR sequence. I've attached a screen grab from a locally running copy of Argo. As you can see it's looking a little ragged and this is about the way I show up on several grabbers. I've been admiring those ops who are getting nice sharp edges to their transmissions. I'll probably be switching over to DFCW05 for the New Year's Eve event.? Again thanks for your help and running? your grabber! --Al WD4AH |
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Re: qcx problem
Joel Fournol
Hello ALAN ,
toggle quoted message
Show quoted text
I have testing with 100?h inductors,the résults is the same 73 jo f6cht. Le 12/12/2017 à 16:04, Joel Fournol a écrit?:
hello Alan i have 20mhz good and 27mhz good thanks for your hep today? i have receved encodeur sending by Hans but receiver is shudown just bf running 73 jo?l |
Daniel Ekman SA2KNG
Enno Korma, PF5X