The power reduces as the input voltage does -?
IIRC the ¡®raw¡¯ supply runs the last few op amps on RX, the backlight and the PA.
The limit is around 7V into the 5V regulator which is more like 7.5 at the input jack, ?the backlight and OP amps are still just about OK at that level ?
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SOTAbeams, a company in the UK, sells a "Milliwatter extreme" that is a 5 watt, 50 Ohm attenuator, with a choice of 10 dB or 17 dB attenuation. The device attenuates the transmission, but bypasses for reception. I have used mine for WSPR tests and it worked well for me.
This solution is not going to help with extending battery life, though.
Ian VE6IXD
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Re: QMX if Vaudeville Still Existed
Winding a toroid is more like this...
https://youtu.be/MYP1OBZfFK0?si=OF3Iifb3XMsnPK_K
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I run my qcx+ at 8v with 1 watt out for wspr. somewhere between 8 and 7 v the rig display starts to fade on tx. My mini will run down to 7v but is still doing 1 watt at that point.
I too would like to run it lower if anyone figures out how it can be done.
--
regards,
Bryan, N0LUF
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QMX if Vaudeville Still Existed
Wind a Toroid? ?Slowly I turn, step by step, inch by inch¡.
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Re: QDX version 1 voltage regulator mod?
On 26/02/2024 11:05, Alan G4ZFQ via groups.io wrote: (I also run a U3S at <100mW for 17-10m, don't think more is needed.) I did not mention my 5th QDX, a V5M for experimenting. It is on a breadboard with a 317 regulator for the PA. I was running at ~1 Watt 5 volts on the PA. I've just tried 2024-02-26 12:12:00 K9AN 3 6483 -28 EN50wc 14097012 17 G4ZFQ ~60mW with 1.2 volts. I claim the lowest power from a QDX with 4 good BS170s:-) 73 Alan G4ZFQ
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Re: 10W HF Linear Power Amplifier
#10W_PA
What should be the resistance between +12 and ground? I have open circuit which is obviously not good, and the PA is not working. Maybe I have fried a mosfet while soldering since I had a nasty solder bridge that took some heat to fix?
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Re: Really trivial bug on GPS display QMX
Hi Paul M1CNK
> I spotted a really trivial bug in the GPS display from terminal? > on the QMX in version 1_00_016 of the firmware
> The month is a month out - took the following snap on 17th Feb,? > not Jan.? The UT Date is out by a month.? Really not an issue? > but mentioned in case the code is used elsewhere.
Thanks for the feedback, I have corrected this for the next version.?
Hi Robb K5RAB:
> Another nit... if I recall, there was something about? > December.? I think it said "Dev" instead of "Dec" or something > Obviously I can't check now.? But can you check on it Hans?
I checked, and you are right, a typo! It had "DEV" instead of "DEC"... so I have fixed this for the next version too.?
73 Hans G0UPL
I spotted a really trivial bug in the GPS display from terminal on the QMX in version 1_00_016 of the firmware
The month is a month out - took the following snap on 17th Feb, not Jan.? The UT Date is out by a month.? Really not an issue but mentioned in case the code is used elsewhere.
73
Paul
M1CNK
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Morning,
That¡¯s for the information, really appreciate it. Have a great day.?
73
On Sunday, February 25, 2024, 11:58 PM, w6csn@... wrote: John, I broke a couple of the leads on the switch side of the encoders during assembly. I fixed it by replacing the missing lead with a thru-hole component cutoff (like the ones used on the display). Just be careful not to short the board end of the lead to the metal body of the encoder with a solder bridge.
The encoder leads clearly aren't designed to be bent back 180 degrees as they are in this application.
Also, I recommend to take the advice in the assembly manual to ¡°shore up¡± the center lead on the 3-lead side of the encoder using a cutoff, since it now has a longer distance to reach the board than the others.
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Re: #qmx filter testing and adjustment
#qmx
Hi Eric,
assembly_1_02a.pdf on page 36 shows a picture of L401 with "an example of the wire spacing we have found to work well,"
Maybe this could help.
73, Ludwig
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Re: #qmx wrong inductances for LPF?
#qmx
On Sun, Feb 25, 2024 at 11:05 PM, @Ludwig_DH8WN wrote:
The harmonics suppression was at least 56 dB so more than ok.
One additional Information: at least 56 dB up to 35 MHz at least 59 dB around 42 MHz at least 61 dB above 50 MHz So it's fine according to regulations.
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Re: QDX version 1 voltage regulator mod?
On 26/02/2024 09:45, Stephen Farthing G0XAR JO92ON97 wrote: I built my QDX vsn 1 from the first batch for 9 volts. Steve, Like Evan I've built mine for 12 volts, run them at 7.5 volts. As I only want 1 watt for WSPR I also have 2 or 3 diodes in series with L14. 4 version 1s, run this way obviously no problem, no PA mods. I run with WSJT-X, one on a Raspberry pi. (I also run a U3S at <100mW for 17-10m, don't think more is needed.) Has anyone tried using the QDX with a microcontroller for WSPR? Do you want RXTX? I guess the WSJT-X functions could be put in a micro, I do not remember anyone doing that as a separate project. 73 Alan G4ZFQ
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Re: QMX 1_00_017 TX indication persists after transmission on new LCD driver version.
Hi Andy
Thanks for the feedback, I added your observations to my bug list to investigate.?
Hello,
Under certain conditions or procedures, while in DIGI mode? the LCD appears to freeze the power and S meter output after a transmit cycle, indicating that a transmission is still occurring, even though the radio is in RX mode (based on the expected sounds of the band on the audio output)?
A second transmit cycle will usually remedy the the issue - it's purely cosmetic and the radio seems to operate fine. It is however disturbing to look at the display and see a transmission in progress when the ears and waterfall say otherwise.?
UNFORTUNATELY, and I apologize, I am not able to reliably reproduce this bug feature, except that I see it on 17M and 20M, DIGI mode (not CW)? on WSJT-X, because that's where I usually operate. This did not happen with 1_00_014. No updates to WSJT-X have been made.
Have others encountered this? And can YOU reliably reproduce it? How?
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Re: QDX version 1 voltage regulator mod?
Steve,
I still have my Rev 1 QDX running.? It is built for 12 volts, but I run it between 8 to 10 volts.? That, to me, supports Hans's statement.? The one mod that I suggest is adding a 1n4148 diode across L14 to prevent the end-of-transmission spike observed on the QDX.??
The AMS1117 regulators have a low dropout voltage, so you can run it at a lower voltage than the 7805 replacement.? It should be good down to just above 6.2 volts.? That gives you a lower power option than the replacement with a dropout at 7 volts.
73
Evan
AC9TU
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Any French compulsive kit builder reading this board ?
Hello all,
With my club, we are organising a "conference" for QRPers : I would want somebody to talk about kit building. Anybody here willing to make a small presentation ? It doesn't have to be fancy, just good enough to convince people that you can homebrew your kit without being an HF engineer !
Avec mon club on organise une rencontrer pour les amateurs de QRP ( ). Je cherche quelqu'un qui accepterait de parler de montage de kit. Pas besoin d'une pr¨¦sentation super ¨¦labor¨¦e, je voudrais juste convaincre les OMs qu'on peut faire sa station soi m¨ºme sans ¨ºtre un ing¨¦nieur de haut vol!
73,
Yannig - F4IUJ
PS : I hope that the slightly off topic subject is OK!
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Re: QDX version 1 voltage regulator mod?
Hi Steve
Replacing the voltage regulator wasn't necessary. It IS necessary to make sure you fit the 10uF electrolytic capacitor across the 12V supply voltage. If that was done, the AMS1117 should be fine. And even more so, considering that you are using a lower voltage?9V supply.?
On Mon, Feb 26, 2024 at 12:45?PM Stephen Farthing G0XAR JO92ON97 < squirrox@...> wrote: Greetings from England,?
I built my QDX vsn 1 from the first batch for 9 volts. Tested it and tried it out then put it aside. Now I want to use it for WSPR. I saw a video which recommended replacing the voltage regulator and taking the output from the higher voltage regulator to the lower voltage regulator. Is this really necessary ? I will probably be running it with less than 9 volts as 5 watts output seems a bit excessive.?
Has anyone tried using the QDX with a microcontroller for WSPR??
I ordered the latest version for the higher bands yesterday. I¡¯m looking forward to building it.?
73s Steve G0XAR?
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QDX version 1 voltage regulator mod?
Greetings from England,?
I built my QDX vsn 1 from the first batch for 9 volts. Tested it and tried it out then put it aside. Now I want to use it for WSPR. I saw a video which recommended replacing the voltage regulator and taking the output from the higher voltage regulator to the lower voltage regulator. Is this really necessary ? I will probably be running it with less than 9 volts as 5 watts output seems a bit excessive.?
Has anyone tried using the QDX with a microcontroller for WSPR??
I ordered the latest version for the higher bands yesterday. I¡¯m looking forward to building it.?
73s Steve G0XAR?
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I had the same problem.? You can order spares from Hans.
https://shop.qrp-labs.com/SPAREPARTS/rotary
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Re: QMX HIGH BAND NO RF OUT AFTER ANOTHER 10 hour WSPR TRANSMISSION
Good morning, I just changed firmware 16 to firmware 15 and nothing has changed, the QMX still doesn't work well, it only absorbs 100 mA in transmission, I seriously believe that the bs 170 transistors are fried, I will replace them as soon as possible with others purchased on ebay, I hope the problem is resolved.? 73
Giuseppe iu8eun
hi Michael, I don't know if it's a bug in firmware 16, but I also did a factory reset and it's the same thing, no RF output, while before it output 6W now it has a current absorption of 90 mA with the light on and in transmission 190 mA, tomorrow I will try to load the previous firmware again to see what happens.? Thank you very much 73
Giuseppe iu8eun
My guess is that this is a firmware bug.
My QMX Low Bander does the same thing if I leave it on over night.
Hans is making great progress though with all the updates:)!
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John, I broke a couple of the leads on the switch side of the encoders during assembly. I fixed it by replacing the missing lead with a thru-hole component cutoff (like the ones used on the display). Just be careful not to short the board end of the lead to the metal body of the encoder with a solder bridge.
The encoder leads clearly aren't designed to be bent back 180 degrees as they are in this application.
Also, I recommend to take the advice in the assembly manual to ¡°shore up¡± the center lead on the 3-lead side of the encoder using a cutoff, since it now has a longer distance to reach the board than the others.
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Bruce Akhurst
Burt Wizeman
Vojislav [YU4HAK]
Don Karon