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QMX+: low RX sensitifity @ 6m / 22 dB noise floor / 1500 Hz wistle
8
Hello, I recently build QMX+ and noticed a huge noise floor and wistling a 6 m. Therfore I measured sensitifity using a signal generator. Band [MHz] Sens [dBm]@Noise+10dB Noise [dB] 1,85 -100,0 0 3,65 -106,0 0 5,35 -107,0 6 7,07 -107,0 0 10,14 -110,0 2 14,23 -107,0 1 18,1 -103,0 4 21,04 -99,0 9 24,9 -97,0 7 28,1 -103,0 5 50,5 -79,0 20 Method: injection of signal Rx frequency + 1,1 kHz Mode: Digi Noise: signal detected by WSJT-X Sens: Noise floor + 10 dB Noise floor is increasing by frequency, but at 6 m wistling and digital noise make RX unusable. Output at 6m is about 2 W at 9V Vbat (12V Version) 1,5 kHz wistle starts at 20 m and is increasing by frequency Using wsjt-X i evalating waterfall diagram: (QMX+ at 50 Ohm) AVE:1, cumulative Noise [dB] : signal by WSJT-X signal in waterfall diagram AU QMX+ freq [Hz] freq [Hz] freq [Hz] freq [Hz] freq [Hz] freq [Hz] Frequency [MHz] Noise [db] Noisefloor 500 1000 1500 2000 2500 3000 1,84 0 0,2 0,2 0,2 0,8 0,2 0,2 0,2 3,57 0 0,3 0,3 0,3 0,7 0,3 0,3 0,3 5,3 1 0,5 0,5 0,5 1 0,5 0,5 0,5 7,04 5 0,8 0,8 0,8 1,1 0,8 0,8 0,8 10,1 1 0,5 0,5 0,5 0,5 0,5 0,5 0,5 14,1 1 0,5 0,5 1,3 2,8 2,1 0,5 1,5 18,1 5 0,8 1 1,8 2,3 2,1 1,1 2 21,1 7 1 1 2,1 2,6 2,1 1,1 2,1 24,9 7 1 1,2 2,7 2,8 2,7 1,3 2,5 28,1 7 1 1,2 2 1,5 1,5 1,2 2,2 50,3 22 1,8 2,5 3,8 4,2 3,9 2,8 3,8 At higher bands 1,5kHz signal is constant and independent from RX freuqency. At 6m additional audio signals are appearing. 6m RF Filter seems to be ok. Any suggestions to detect cause? vy 73 Michael (DF6TV)
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QMX+ First 1000 QSOs Impresions
3
After initial hickups after assembly, i deployed my QMX+ as base/main rig. 3 months have passed making QSOs with it and the following is the statistic, all FT8 Worked QSO: 1004 Worked DXCC: 86 CQ Zones: 20 ITU Zones:27 Continents:5 Longest contact: Fiji 16231km Other than that i made contacts with few Australia 15400km and New Caledonia 15900km away from my QTH All results on 20M with 3.2W and under the roof dipole. Overall very happy with how this rig performs, nothing can beat the price range vs performance it provides. Bad weather here is over, time to deploy some new antennas for this bad boy, and improve the statistics :)
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Jeff Moore W1NC - QMX Rev. 1 Repair
3
The QMX Rev. 1 that I had assembled some time ago recently stopped working after making many CW and SSB contacts with the beta SSB firmware. By-the-way, the calibration went nicely. No issues there. It would turn on with no display but wouldn't turn off. Certain the CPU was dead, I was contemplating chucking it in the spare parts box and just continuing on with my QMX+. However, I decided to send it to Jeff to see if he could salvage it, and I'm glad I did. Jeff discovered the CPU wasn't dead and was able to get it working again in perfect order. His turnaround time and explanation of findings was great. If your QMX goes down I highly recommend Jeff to get it working great again. If it's beyond your repair capability, he's got the experience, tools, test equipment, parts and talent to make it happen. Thanks again Jeff. 72, Randy NR5N
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PTT over CAT - WSJT-X vs fldigi
#fldigi
#QMXplus
#ssb
#wsjt-x
I just updated to the new SSB firmware on QMX+ Rev. 3 and was hoping to try out MSK144 mode in WSJT-X. (Probably not enough power to be heard by anyone, but still.) I have found the PTT over CAT control to be inconsistent when in USB mode. Usually the first TX works and then the rest briefly trigger then un-trigger PTT. (DIGI mode still works just great.) Looking at the CAT monitor doesn't show anything odd (no early RX; sent) and it's not triggering SWR protection or anything. PTT over CAT in USB mode in fldigi---also using Hamlib, same Kenwood TS-480 config---works fine. As far as I can tell, the only difference is that WSJT-X is sending either 'TX;' or 'TX1;' depending on the configuration; while fldigi is sending 'TX0;' which for some reason is more reliable in convincing the QMX+ to transmit. Is anyone else having this issue? Any suggestions or ways to convince WSJT-X to send 'TX0;' instead? TNX 73 de Tim AF0CQ
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QMX Build Not powering up. IC101 gets hot
2
Hi all, I completed my QMX build, and it won't power on. I took my time and was very meticulous. Or so I thought. When I power it on with the left encoder, nothing happens but I notice that IC101 gets slowly warm then hot if I don't pull the power. I can have the power connected but IC101 doesn't get warm until I press the left encoder. I can also connect it to my laptop and see it, but I don't dare leave the power connected for long. Has anyone seen this or have recommendations on where to start troubleshooting? Many thanks Aaron
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PIN diode bias current unstable
36
#qmx
Hi all, I built my Rev 1 QMX kit a while back and got bitten by the shorted diode on the SMPS board. After fixing that, the QMX works very well. However, in the hardware diagnostics screen the PIN diode bias current is all over the place. If I put the rig into transmit with the dummy load the current goes from about 17mA to about 70mA and everywhere in between. Any idea if this is an issue and where I should start looking? TIA. Jason
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Use original IC after Firmware Update
2
Hi, I try to upgrade the firmware of my gcx mini, and mess up the fuses. after I corrected it to avrdude -c usbasp -p m328p -U lfuse:w:0xF7:m -U hfuse:w:0xD1:m -U efuse:w:0xFC:m It shows the use original ic on screen :( Is there a trick i can do, to bring it back to life? Regards Andreas / OE9ROE
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SSB firmware and QRP Labs
7
Hi All, At 63 my mind id blown at how fast and cooperative these projects are going. I do not have the balls or knowledge to dare install a Beta firmwhere on my QRP QMX, but I am eagerly waiting for the official release. Thank you all! Rgds, a.
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Scripting language?
5
Hello! I just upgraded my QMX+ to the current official version with SSB. Got good reports on the 40M swap net. Woohoo! I was using it with my "Tiny Linear" project, which is a 70W amp crammed into a too-small enclosure, with a switchable LPF salvaged from a defunct Yaesu 756-Pro radio, and a cute little touch screen in the front. I am beyond impressed... clean SSB out of a digital PA. I'm thinking of integrating the QMX+ ( or the QMX - I've got one of those too ) into another project: my "Medium Linear". This is a pair of MRF300's in a wraparound case from a Heathkit Single-Bander. No, I didn't cannibalize an actual Single-Bander - the case was a flea market buy. A QMX or plus integrated into the Medium Linear would turn it into an integrated 400W transceiver. But to do that, I need to get at least the band info out of the QMX+. Given that the software is closed-source...and encrypted, I have no reasonable way to figure out how to do that. Yeah, there are select signals on the card, but the LPFs are shared between bands. My linear also shares LPFs, but possibly different ones. Hans was going to implement some sort of scripting language. Maybe that could leave the back burner now that SSB is real? - Jerry, KF6VB
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Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
91
#ABS
#ATU
#PSU
#QMXplus
Hi, I have released a version 1.2 of the solution. Please refer to the readme front page file at the git repository with details: https://github.com/AC8L/QMX_Plus_Autotuner_Internal_Battery_Speaker/ While I am writing this note - a group buy with 35+ participants is happening for this same version 1.2 - organized by Cal (AD8Q) and Stan (KC7XE). -- 73, Sardar (AC8L, 4K6SA, VA3DUA).
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How would one use a ProgRock2 in a Colpitts crystal oscillator? A crystal is essentially an LC circuit, while the ProgRock outputs a square wave. Can the ProgRock2 simply replace the crystal? If so, will the Colpitts circuit turn it into a sine wave? Does the ProgRock2 start up at the last frequency used before its last power down? Steve, N9SZ
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QCX+ latest firmware hex file link
3
Can anyone give me a direct URL for the latest QCX+ mega328 firmware? I found a link to the T1_08.zip file through this board but not seeing a link to the latest (1.09a ?) TIA. Charles.
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When Elecraft introduced the KH1 a year ago, I was immediately enthusiastic about the concept. A small and lightweight shortwave radio with an integrated telescopic antenna. This means that, weighing less than 400g, it can be used in any suitable location on shortwave. So I wanted to build something myself. I immediately began my own experiments with telescopic antennas for 7-30 MHz. This confirmed that a counterweight is absolutely necessary. This wire, which is a quarter of the wavelength long, contributes significantly to the radiated energy. So the idea arose to forgo the telescopic antenna and experiment with end-fed wires twice the length. Of course, it makes sense to stretch the wire as high as possible. But I also got respectable reports with EFHW lying on the ground or in bushes. In this place the antenna may detunes itself, so a tuner is necessary, as well as the standard 1:64 transformer (Unun). The tried-and-tested resonance circuit (Fuchs Kreis) performs both tasks. Once the antenna issue was resolved, QRP Labs brought out the QMX. The ideal TRX for my projects, and now even capable of SSB. Now all that was missing was a suitable housing with an integrated battery and a speaker with an amplifier. Then a paddle for CW as a contactless touch key directly on the device. And the QMX Carrot was finished. But it wasn¡¯t that simple, because everything had to be as small and light as possible. It now weighs 340g and measures 15x8.5x3.0 cm. I¡¯m happy with that. 73 Chris https://youtu.be/0kksiWVOtnQ
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QMX, WSJT-X 2.7.0, Hamlib 4.6.2 DLL - Odd Behavior
7
When I power up my low-band QMX, put it into DiGi mode, then start WSJT-X in FT8 mode, I get tons of decodes. If I then enable transmit, it will transmit with about 3.5 watts on 20m and my signal, as reported by pskreporter.info, covers the entire United States (at least today). However, after that first transmission my decodes stop. Even though the QMX is still in DiGi mode, I can no longer hear FT8 stations. If I then put the QMX into USB mode then I can hear lots of FT8 stations and decoding resumes, but as soon as WSJT transmits it puts the QMX back into DiGi mode, I can no longer hear FT8 stations, and the decoding stops. My transmitted signal continues to be heard throughout the United States. Any suggestions as to what I'm doing wrong? Best, Jim / K8DDV
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QMX USB device not recognized by windows
4
Hi all, I tried to update my QMX today to the famous SSB SW. But the QMX is not shown as drive in the explorer, although it has worked before several times in last year. I tried all remedies utube offers: Re-install USB device drivers, USB root, power settings, repair windows etc, nothing worked. Even 4 different PCs, win10, win 11 and laptop with linux Mint. All tell the same error message.. Did also a factory reset of the QMX and used 3 different USB cables. No success. The PC see the device, but due to missing name do not not proceed. Could it be a fault in the QMX? Has anybody any advice out there?
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Feature Request List?
30
Hi Hans, Is there a maintained Feature Request list available somewhere where we can check if what we¡¯d like to see has already been asked for, and perhaps add a vote? I know posts can get lost in the volume, and I expect that is why there was no answer on my question on having variable TX power available as a setting (/g/QRPLabs/message/143397), but I don¡¯t want to bug anyone, so if there was a tracker we could look at, it might save you getting duplicate requests or being bugged by people like me :-) Love the pre-built QMX, am going to get a QMX+ kit to have a go at¡ 73, Stefan MI0PYN
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QMX+ VOX
5
I waited for and yesterday installed the 1_02_000 firmware. I did a bit of tinkering with the EQ to get some more emphasis in the mid-range (and worth noting that when I do live sound at folk dance events, I always cut back the bass and emphasize, not too much, mids and highs to improve intelligibility of the dance leader, just as Hans suggests). And I made 4 SSB contacts on 20 meters with some Italian stations in a contest setting .... running about 75 watts with the QMX+ and my HR-50+ amplifier. Worked great. Thank you, Hans ... you are a wizard! One glitch ... I cannot get VOX to work. I'm using one of Erik Larsen's microphones, which clearly works fine in PTT mode and sounds OK. I set microphone gain using the built-in Mic Test ... goes red on just the loudest peaks. On USB, speaking into the microphone apparently triggers the VOX, but it then cycles on and off until I manage to get QMX+ mode out of USB over to LSB. LSB doesn't work at all ... speaking into the microphone does not trigger VOX. Input device is set to "External Microphone". And I'm using TRS (stereo) 1/8" mini cable between the microphone and the QMX+. Any hints will be much appreciated! Thanks - Bruce K1FFX
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Hello QRPers I would like to suggest an improvement I did in MIC circuit in my QMX+. Existing circuit is quite simple and powered from not very clean VDD. By adding two capacitors (100n, could be more) and two resistors (33k, 1k) I was able to reduce the audio noise on the other side receiver by 6 to 8 dB (simple check with Audacity peak meter on two recordings, before and after, FT-891 as a receiver). This will improve SSB signal, especially on higher bands (low band noise). I assume the same will apply to the internal mic circuit. It would be also good to use filtered VDD, same as for microcontroller ADC (from C214), but I did not wanted to have a wire across the board. Maybe a separation resistor on the microcontroller key/paddle line can also help but I think most of the noise is getting in because of dirty digital supply used for bias. I think it is worth to consider in case of next PCB revision, both QMX and QMX+. 73 Pawe? SO8FM
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#qmx #problem #troubleshooting
#troubleshooting
#qmx
#problem
Hi everyone, I've been using my QMX for about an year with great joy and happiness when suddenly my QMX stopped receiving or transmitting. I'm fairly new to radio and i am struggling to find the problem. The sweeps are all garbage on all freqs: RF filter sweep, Audio Filter Sweep, everything but the LPF sweeps. The Voltages seem good although when I press "T", the transmitter voltage shows 9.8v in red. My QMX is 12V. I have little knowledge and i need a hand from you guys, to know where to start. I zipped and attached the image sweeps. 73 Pedro - CR7BJL
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Firmware updated to 1.02_000 - QMX has changed from 60/40/30/20/17/15 to 80/60/40/30/20?
4
Hello! As the title says, I've just updated the firmware and now seeing my radio is showing as 80/60/40/30/20m rather than the 60/40/30/20/17/15 version that was built. I wondered if anyone has any ideas of how this might have occurred? Many thanks! Alastair 2E0UOE
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Image Name
Sat 8:39am
Sat 8:39am