Re: To socket or not to socket, that is the question!
On 09/05/2025 08:55, Bruce Akhurst via groups.io wrote: move the socket contact surfaces very slightly It's less of a problem with turned pin sockets than with the cheaper flat contact type. Early Apple II computers (1978-1982) used to suffer from chip creep. I used to fix them for the local computer shop in my Saturday/holiday job. Normally first procedure was the "high G manoeuvre". Place Apple II on workbench, remove lid, remove expansion cards, lift front of computer about 10cm above desk with rear sat on bench. Drop. After the bang as it hit the bench, reinstall expansion cards, power up and most times normal operation was restored. More electronics based fault finding took place if this failed. ;-)
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Re: To socket or not to socket, that is the question!
I am confident that the surface area of the socket, the tight fit of the leads in the socket and the force of the lead bend against the socket ensures that there is a positive connection that won't degrade in time.?
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Well perhaps you are confident. ? Like tektronics R&S and many other professional equipment makers in the 70¡¯s who moved to sockets and were then subject to a huge failure rate after a few years. ?Literally the first place to start diagnosis was a few known ¡®bad sockets¡¯?
This was not about some small sample of misused equipment. ?I was sat in the repair dept ?! ?
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You missed my point. ? Perhaps if your devices stand free and run cool in their sockets (not a description of PA BS170s) they will be fine?
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¡ but if thermal expansion or other forces move the socket contact surfaces very slightly in every thermal cycle and while carrying significant current they will degrade.?
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Re: QMX+: low RX sensitifity @ 6m / 22 dB noise floor / 1500 Hz wistle
Hello Dan,
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firmware Vers 2 is installed,
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Several resets to factory serttings didn?t solve the problem. Wistle is still present.
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During reset I hear the 1500 Hz wistle in my headphones.
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vy 73 Michael
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Re: QMX+: low RX sensitifity @ 6m / 22 dB noise floor / 1500 Hz wistle
Hello Don,
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in USB and Digi 1500 Hz wistle is dominat in audio, but also in LSB and CW wistle is present.
At 6m band additional digital noise is present.
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vy 73 Michael
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Hi Guys,
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the SSB modus for the QMX is awesome. Even with a small Magnetic Loop antenna.
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I?m Using a microphone of the QRP-GUYs from California, USA. At the Antenna connection (bnc) I also use a LED SWR bridge from the QRP Guys. So I can tune my magnetic Loop antenna with full power about 4 Watts with 11V Supply(3 Watts keep in the bridge resistors..lol, 1 Watt will be used for the measurement) . When the LED goes out, I can switch into the operation mode. I NEVER switch of the SWR Protection off (SWR3 in the Menue of the qmx).
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Has anybody an idea, if the internal microphone can be activated in the nearer future or will there maybe have to do any hardware change ?
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enclosed my? video? :) :
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By the way, I?m using a DC-DC converter to reduce the voltage to 11-11.5V . And yes, it doesn?t make any noise, believe me, Its a quality module from an european electronic supplier and not a cheap piece of sh.. from Temu ! Im using toroids around the voltage supply cables (lpf).
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Have much fun with the QMX. YOu really did a great job Hans ,
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72 de Matt, DL1SER
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Hello. While I await my QMX+ to arrive so I can experiment, I joined this Group and searched for a few topics that come to mind, but did not find much information. The users here are very knowledgeable about the QMX+ and I am hoping others will provide some insight to these questions. Thank you all in advance:
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1. Can the QMX+ be controlled by Thetis??
2. If yes to question 1, do "Radio Model" profiles for the QMX+ exist in Thetis?? I only see Hermes and ANAN profiles.?
3. Will the developer kit allow the addition of an Ethernet connection?
4. If yes to question 3, will it also allow PoE?
5. Could the QMX+ be powered by USB-C?
6. Could WiFi be added to the QMX+??
7. Can the QMX+ be operated remotely over the Internet?
8. Can a USB microphone connected to the PC be used with the QMX+?
9. It appears that the QMX+ makes use of some form of pre-distortion. Can this be used with an external amplifier (e.g., Mercury Lux)? The Hermes Lite 2 has an additional SMA connector for Pure Signal. I don't see one on the QMX+.??
10. Any heat concerns with high-duty cycle modes (e.g., FT8)?? The Hermes Lite has a heat sink shim that dissipates heat via the enclosure. I did not see anything like that for the QMX+.?
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I really like my Hermes Lite/Hermes Lite 2+ but appreciate the wider band coverage and some of the intelligent engineering present in the QMX+. I look forward to experimenting, but hopefully others further along in this journey have already sorted out answers to the above questions. Thanks in advance for any replies.?
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73,
Frank - KG9M
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Re: QMX+ First 1000 QSOs Impresions
On Thu, May 8, 2025 at 03:57 PM, N4REE - Bob wrote:
"under the roof dipole."
Any antenna is better than no antenna ?
Since it was harsh winter here and climbing roofs etc. was not option that was the best solution. Band conditions were good so after a month of usage it was not strange to see more than dozen DX stations in waterfall at the same time.?
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Re: To socket or not to socket, that is the question!
I lost a final after about an hour of WSPR at full power.? I chose to socket mine as insurance against future misadventures.? ?I am confident that the surface area of the socket, the tight fit of the leads in the socket and the force of the lead bend against the socket ensures that there is a positive connection that won't degrade in time.? To date I have done three SOTA outings and a POTA outing and have not had any adverse effects. Hopefully I won't lose another final.? If I have to replace one on the lower portion I think it will be a tighter fit to get a socket in there.? Will burn that bridge when I get to it.
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Brien - KE7WB
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Re: Jeff Moore W1NC - QMX Rev. 1 Repair
QMX+ sorry
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73 Michael N6QP
Up in Thin R
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Re: Jeff Moore W1NC - QMX Rev. 1 Repair
I totally agree. I have a Rev. 1 QMZ+ that I built recently. It had the misfortune of having one of the non-functional 1804 chips. I tried to replace myself, but made a mess of it. I sent it off to Jeff and he did a detailed analysis, a meticulous repair and then did a thorough check on the unit.
I finally had time to go out for a POTA with the device and it performed magnificently. Thank you so much Jeff for your wizardry!
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73 Michael N6QP
Up in Thin R
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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.)
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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.
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PTT over CAT in USB mode in fldigi---also using Hamlib, same Kenwood TS-480 config---works fine.
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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.
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Is anyone else having this issue? Any suggestions or ways to convince WSJT-X to send 'TX0;' instead?
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TNX 73 de Tim AF0CQ
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Re: QMX Build Not powering up. IC101 gets hot
Hello Aaron
That would happen exactly, if you haven't installed the firmware yet. Have you installed the firmware? If not please follow the steps in the manual.?
73 Hans G0UPL
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?
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Many thanks
Aaron
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Re: PIN diode bias current unstable
#qmx
Sorry to resurrect an old-ish thread but I wanted to drop in and say (1) thanks for posting as I had the same problem and (2) for me, replacing just Q516 fixed the PIN bias entirely.
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I was able to suspect Q516 in particular using a multimeter diode test across the neighboring diode, which is connected in reverse across the B-E junction of Q516. Diode test therefore SHOULD read a ~0.6V drop in both directions, but in my case, one way was an open circuit that corresponded to the diode working, Q516 failed open.
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The remaining nearby FETs and diode managed to survive my tactless de- and re-soldering (lucky, though I ordered spares just in case).
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By the way my replacement part was labeled 6B instead of 6C but it seems sufficient.
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73 Tim
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Re: Amazon Microphone for QMX ? QMX +??? Suggestions
I bought this $12 headset on a whim and have to say, I'm impressed. My plan was to cut the cord and split the wires into different connectors for mic/ptt & speaker, but it came with a splitter that already did that. So, I plugged the mic into my adapter & PTT box and the the headphones into the QMX+. Everything worked great. The earpieces measure 34 ohms at DC, so I assume they are 32 ohm impedance, a good match to the rig and sound quite good. I tuned around 40 meters and heard a POTA station in CT calling CQ, so I gave him a call and he came right back with a 57 signal report with good audio. Not bad for about 4 watts into a EFHW. He was running 10 watts and was 59 here in Los Angeles.
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QMX Build Not powering up. IC101 gets hot
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?
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Many thanks
Aaron
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Jeff Moore W1NC - QMX Rev. 1 Repair
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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Re: QRPLabs 50W Amplifier - 20V Power Supply Solution
I have found a great variety of 3D printed battery adapters/breakouts on EBay for my Dewalt 20V and EGo 56V batteries and have various fixed and variable converters which run off them.
No hacking needed but I can envision a use for the stupid flashlight I got with my Dewalt set.??
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The 56V 7.5A EGo lawnmower battery is a monster, 420W-hr (1.5megaJoules) and I have pulled 400W (the limit of my electronic load) from it no problem.
No RFI noted from the converters.
73, Don N2VGU
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On Thu, May 8, 2025 at 06:56 PM, Brent DeWitt wrote:
I just setup NaP3 and everything is working exactly as advertised.
Would you share a connection/block diagram and perhaps NaP3 setup screens?? I want to set up a panadapter with my QMXs as well. Any gotchas?
Thanks and 73, Don N2VGU
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Re: QCX-mini LCD backlight not coming on
Jeremy, if you have 5v on LCD pin 16 and close to zero volts on the drain of Q100, then you need to check continuity from LCD pin 16 to Q100 drain. They are supposed to be connected together. Having said that, it also looks to me like either the gate of Q100 is shorted to its source, or C100 is shorted. That could be checked by removing C100.
Ron
On Thu, May 8, 2025 at 6:45?PM Jeremy Ollerenshaw via <ollerenj= [email protected]> wrote: Hi Ron, Thanks again for your quick response. I checked voltages in the LCD pins and I have 5V on pin 14, 12V on pin 15 and 5V on pin 16. On Q100 I have very low voltages on all 3 terminals (0.2V on the gate, 0V on bottom terminal (possibly ground) and 0.1V on the top terminal. I have continuity of LCD pin 14 to IC2 pin 5. R100 has 5V on front end and 0V on back end, C100 has 0.2V on both ends and continuity with R100. I was able to get the backlight to come on at one point by grounding LCD pin 16, so the backlight is capable of working. Does it sound like Q100 is bad, and if so, are these easy for me to find so that I can replace it.
Jeremy
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Re: QCX-mini LCD backlight not coming on
Hi Ron, Thanks again for your quick response. I checked voltages in the LCD pins and I have 5V on pin 14, 12V on pin 15 and 5V on pin 16. On Q100 I have very low voltages on all 3 terminals (0.2V on the gate, 0V on bottom terminal (possibly ground) and 0.1V on the top terminal. I have continuity of LCD pin 14 to IC2 pin 5. R100 has 5V on front end and 0V on back end, C100 has 0.2V on both ends and continuity with R100. I was able to get the backlight to come on at one point by grounding LCD pin 16, so the backlight is capable of working. Does it sound like Q100 is bad, and if so, are these easy for me to find so that I can replace it.
Jeremy
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Bruce Akhurst
Ivica - YU1QRP
Brien - KE7WB
Michael N6QP
Lawrence KC6WOG
Donald S Brant Jr
Ronald Taylor