Indeed! ?I would also like to add my thanks to Jeff Moore, W1NC - he is the guy to go to. ?Like you, I had a problem (several really) with my QMX build. ?Jeff did a great job with the repair, kept me informed, and provided a detailed list of what was done. ?
This forum and Jeff are extremely helpful.
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Dave, AD8LM
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hi, may i`m wrong with some qmx+ config, but sending cw from stored messages isn?t possible without loosing some characters, as like as "cq de df4bj" may ends in "ca de dfuba" or something else. Same behavior if sending from logging programm via cat. Did i don`t have correct configs or is that an known issue?
I have installed the v1_01_003, updated from 1_00_027 on QMX+ Rev 3 , but going back to a non ssb fw doesn`t help.
any suggestions ?
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vy 72/73 de Udo DF4BJ /qrp
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QRP Labs kit shipping update
Hi all
During my absence on family vacation last week there was a major storm last Thursday, a lot of rain and thunder and lightning. After one close-by strike my colleagues?reported crackling and sparking on cables in our office, and since then we have?been without internet... the ISP say the modem is working fine (they test it from their end) but we tell them it isn't actually delivering us any internet.?
Anyway regardless of that, today I woke up and figured out how to USB tether my cellphone to the PC and share the internet to the PC. And got my shipping colleague doing the same thing via her iPhone. So 2 of our 6 QRP Labs office computers (which are the most critical two) are back online while we wait for someone from the ISP to visit. We are now working?on catching up on the shipments from last Thursday to today.?
Meanwhile after all the crackling and sparking my colleagues thoughtfully?unplugged my antenna. Full marks for effort... but the damage was evidently already done by that time: when I returned from vacation and switched on my QMX+ the thing popped and current went to several amps... I replaced the four BS170 PA transistors (one of which was visibly cracked); still not getting correct power output and performance I realized I need to replace the Q508 Tx/Rx transistor which had also apparently taken a hit. After all that, happy to say everything is back in order, the radio is working properly once again!
Meanwhile: we ran out of dummy load kits, and the 1.000 new PCB's are on the way via FedEx. They are going through customs processing in Izmir today and after that the imports normally reach me about 2-3 days later by road via the domestic courier who are the local FedEx agent. So some of you who ordered a Dummy load kit might be wondering why your order didn't ship yet, this is the explanation, please wait a few days.
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Record number of assembled transceivers shipped in March
Hi all
I have updated the assembled kits page?
In March 2025 we shipped 280 assembled transceiver orders (some containing more than one transceiver). This is a record high number. The waiting time for assembled transceiver orders is currently around 1 month.?
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On Mon, Apr 7, 2025 at 08:28 PM, james jones wrote:
I’m going to touch up all 16 of the display header pins. What a bad place for a soon to be 83 year old duffer to be soldering. Why couldn’t that bave been added to the display board before mounting?
It can be, assemble the front PCB, 16 pin connector and display using bolts and nuts between the display and the front PCB.? Solder the 16 pin connector pins to the display only.? This does the inaccessible contacts without the front panel in the way.? Disassemble and reassemble with the front panel, spacers, display, nuts and front PCB.
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You can also disassemble it when it's all assembled, remove the rear nuts then unscrew the screws, taking care that the various spacers and nuts aren't turning.? Just take your time.? I know because I also missed a soldering one of the pins.
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Chris.
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Re: SWR and PWR does not show lcd
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hi, may i`m wrong with some config, but sending cw from stored messages isn?t possible without loosing some characters, as like as "cq de df4bj" may ends in "ca de dfuba" or something else. Same behavior if sending from logging programm via cat. Did i don`t have correct configs or is that an known issue?
I have installed the v1_01_003 , but going back to a non ssb fw doesn`t help.
any suggestions ?
?
vy 72/73 de Udo DF4BJ /qrp
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Re: SWR and PWR does not show lcd
For test switch please display voltage ON.
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Re: SWR and PWR does not show lcd
I've tried your recommendations several times, and it doesn't work.
I've attached photos of the problem.
1. PWR/SWR Display ON
2. Hardware Test - My external meter indicates 2 watts and the same SWR.
3. Transmission test in WSPR mode. My external meter indicates 6 watts and? SWR 1.2.
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Re: GPS module GY-GPSV3-NEO wont change baud!
On 07/04/2025 18:25, Michael Pupeza via groups.io wrote: HELP! I need to change my QRP Labs GY-GPSV3-NEO module, which has the UBlox NEO-7M-000 chip on it to 4800 baud, Mike, I do not know what module you are referring to. I have just checked with a uBlox M7 and find I cannot get uCenter to permanently change the baud rate. After a cold start it goes to 9600. I seem to remember I found that before... It does save NMEA sentence configuration. In the past I have used a backup battery which will save configurations. Perhaps there is a uBlox group somewhere? Might give some clue. Although others seem to have the problem Maybe some things are stored on-chip, others in flash. 73 Alan G4ZFQ the old NMEA 0183 standard for the TinyTraker3 APRS units. I can use the UBlox u-center25.03 and everything I receive and send from it appears to work, telling me that the RS232/TTL interfaces that I try are correct. However, going into Messages View - UBX - CFG - PRT - TragetUART1 (or any other) setting BAUDRATE to 4800 and hitting the Send button makes NO CHANGE (EVER). It stays at 9600 Baud!
Is there another way to try this and make the change permanent? Perhaps there is an inhibit connection on the chip? Or some sort of authorization command? Connecting a terminal program gives me the continuous GPS strings so the module is correctly putting out my location etc., so that part is also working fine (at 9600).
I appear to be stumped! Miniature GPS units running at 4800 Baud are pretty rare and I want to resurrect my Altoids Box Pocket Tracker with one to make it truly pocket size, again.
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Hello all,
?
Long time lurker, first time poster here. I recently built a 60m-15m QMX and I am having some trouble getting good reception on 15m and 17m (see attached RF sweeps). I should mention that I am using a Rev 1 board purchased in 2023, but with a mid-band component kit from 2024. Here’s where I’m at:
- I get good power (4-5w at 12V) out on all bands, and my LPF sweeps look like the firmware manual
- 60m-20m RF sweeps look more or less like what’s shown in the manual. I use a QRP Labs 50 ohm dummy load for the sweeps.
- When I connect to an antenna, I can hear FT8 signals on 40m and 20, but not on 17 or 15
- Because the lower bands seem to receive OK, I suspect an issue with L401a, C401 or C403. However, 20m uses L401a and C401 and is OK, but 17 also uses those and is not good.
- I reflowed solder on all 3 taps for L401a and the capacitors, with no change. I’m pretty confident I’ve burned off all the enamel at the junctions at this point. I get continuity at all the points shown in the Rev 1 manual (plus at pin 6 of IC402, which I think makes sense because I’m using all 4 connections for L401 instead of just the 3 with the low band version)
- I did a factory reset, with no change
- I’ve counted the number of turns on 401a more times than I’d care to admit, and keep coming up with the same number I’m supposed to have (24 turns, tapped at 15)
- I confirmed that C401 and C403 are the correct values printed on the component, and don’t appear to have any physical damage
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Trying to figure out my next steps, but coming up a bit short. All I can think of is to replace capacitors, and possibly re-wind L401a. Or, even less ideally, replace IC402. I don’t have an oscilloscope (or any real expertise to use one), so my ability to diagnose is somewhat limited. Before I start swapping out components, is there anything else I should try looking at? It’s been fun building this kit and I have managed to iron out quite a few kinks along the way by reading posts on this forum. However, this one has me stumped.
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Thanks in advance
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Alex, N7ADH
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Re: QMX+ no power output, low SMPS bias current
On Tue, Apr 8, 2025 at 06:51 AM, Stan Dye wrote:
- when you measured the output, did you have a dummy load attached?? hopefully so, unless your scope has a 50-ohm termination option turned on (but most inexpensive scopes don't have an internal 50-ohm termination).
- when you measure, are you measuring ms would be 100mW).?? So please first confirm your measurements.
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Please do not measure the output of a QMX using the internal terminator of an oscilloscope, you have a good chance of magic smoke coming out of the oscilloscope.
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Re: QMX+ no power output, low SMPS bias current
I believe it said to 'solder' it under the board, not 'put' it under the board, which would mean soldering on top.?
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Re: QMX+ no power output, low SMPS bias current
I have successfully used the 330 ones from this Amazon kit:
It is best to use a hot air station to remove/replace, since the contacts are underneath.
I have an inexpensive hot air station, and mask off all nearby components (on both sides of the board) with aluminum tape or kapton tap to hold them in position while I do the hot air work, otherwise they may blow out of position, because their solder may also liquify.
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Re: QMX+ no power output, low SMPS bias current
Looks like the L501 is broken.? Guess I'm ordering parts, and trying again.
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Re: QMX+ no power output, low SMPS bias current
First a couple of basic checks on your measurement setup -
- make sure your scope and probes are set up correctly: most scope probes have a? 1x and 10x option, and it needs to match that same option on your scope, otherwise the readings will be incorrect by 10x
- when you measured the output, did you have a dummy load attached?? hopefully so, unless your scope has a 50-ohm termination option turned on (but most inexpensive scopes don't have an internal 50-ohm termination).
- when you measure, are you measuring peak-to-peak voltage of the sine wave, or an RMS value?? Most scopes report both; peak-to-peak is probably best for debugging
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If the above are done correctly, you are seeing very low power out of the QMX, but real power.? 4W out should be about 40Vp-p, but Tune SWR default is 50% voltage, so about 20Vp-p.?? The 5Vp-p you measured would be 62 milliwatts (5Vrms would be 100mW).?? So please first confirm your measurements.
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If they are correct, it means your BS170s are not amplifying the signal much, if at all - or maybe all your LPFs are turned off due to no bias current, so the signal isn't coming out.
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Most often we don't have a bias current problem, but Jeff has noted that sometimes the L501 gets broken (one of those 330uH coils), or C504 (the big tantalum capacitor) fails.? So you could check those two items.? Also check that L504 and L514 are soldered in properly and not cracked (since I understand they are a bit fragile) - and that your diodes are not soldered in backwards.? Any of these could cause havoc with the bias current.
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Stan KC7XE
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Re: QMX+ no power output, low SMPS bias current
In a spirit of double and triple checking everything, I rechecked continuity for my connections on T507 and T501.? T501 had intermittent continuity between two of the primary windings.? After reflowing the connections, I am now getting a signal out of the BNC connector when I hit Transmit and the SWR has stabilized going into the dummy load at close to 1.0 (except on 6m, which is fluctuating between 2 and 4).? However, I am still getting the extremely low SMPS bias current, and Diagnostics still reports 0W output.? The power meter on the dummy load is showing a little power output (possibly as high as 5W for 160m and 80m, but going down for successive bands).
?
?
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Re: 750 Hz Square Wave from #QMX Speaker while Transmitting
#qmx
#beacon
I suspect that the QMX hardware is generating the steady fixed volume 750 Hz square wave and outputing it through the earphone jack only during beacon transmissions.
This only occurs when the QMX is left in USB or LSB mode during the QMX's built-in beacon transmissions.
This report is merely an observation. There is no apparent malfunction as the transmitted beacon RF is a clean single frequency signal.
AD5DZ also reported observing 750 Hz square waves /g/QRPLabs/message/139807
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Re: Release of version 2.0 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
#PSU
#QMXplus
#audio
#ABS
#ATU
Looking to start a very limited group buy in ZL for the boards only. The other components including hardware etc. Can be selfpurchased from Digikey for about NZD 70 WITH FREE SHIPPING The cost for five boards from JLPCB at today's exchange rate is approx NZD 470 including shipping from China making it approx NZD 92 each.
The order will include the ATU and audio board,? battery/speake board,, front and rear pcb panels.
The cost should cover domestic
shipping from my qth to non rural NZ.
We have three hands up and looking for two more to make it cost effective.
Any ZL QMX+ owners Looking to join please contact me
73
ZL1REY
USPS Shipping fee is US$50.55 to Austria.? I'm not sure if there is any customs fee; I think not, but maybe some.
But that is high enough that it negates the savings of a group-buy, so it would likely be more cost effective to order items directly.
Unless what you value is the convenience...
Stan
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Re: QMX shutting off at 10.5V
Chris, Ludwig,
?
Thank you very much for your returns, now it starts to make sense to me. I won't have time to troubleshoot before this weekend as I am away but I am looking forward to the debugging. Right now I would put my money on something pulling down the 3.3V power supply but I could be wrong of course! I just hope that it isn't the microcontroller.
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73,
?
Yannig F4IUJ
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Udo Die?elberg DF4BJ
Carol KP4MD