Re: QMX in the K1USN Slow Speed CW contest
Thank you, Dick!?
Dosen't work for me, but might be my windows machine.?
HNY!
Simon
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Hello Juan,
there are many possibilities. ?So it¡¯s a difficult question to answer. ?Is this a QMX that you built or built from the factory? ?Is this a Rev 1 or a rev 2 QMX? ?Do you have any test equipment?
jeff
W1NC
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Hello everyone!
Please I need help. I am not undestand nothing of electronics and I want know the reason why my QMX is without audio.
I only turned it on once and I could only make one qso, then there was absolutely no audio.
Please, help me.
73, Juan LU9CYV
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QMX Bugs and Power Supply
Having recently built two QCX-minis I am once again in the building mood.
I hesitate to tackle the build of a QMX as I am seeing a lot of email on the reflector about QMX failures!
My question...have all of the bugs been worked out of the QMXs?
Also I power my QCX-minis from a Bioenno 12V 4.5ah Lithium Iron Phosphate battery which when fully charged puts out 14.46 vdc. Is there a recommended way to drop the voltage from the battery to 12 vdc so I can power a QMX with it?
Ordering a QMX to build hinges on all of the above.
BTW my 20 and 40 meter QCX-minis have never failed me.
73
Jerry WB7S
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Re: QDX Rev 5 High Band Internal Noise
Hey Phil,
Thanks for the idea. My low band QDX does not do that even without any antenna connected and the High Band does so I'm thinking it must be something else.
Recovering from the RSV that's been going around E. Texas. Not fun. Other projects been keeping me off the air much lately. Catch you on the air again soon, Lord willing.
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On Jan 2, 2024, at 08:39, phil - wb4som < mrphilmo@...> wrote:
Hey Cliff,
I had an early problem with this way back when I first got the QDX. In my case it turned out that the BNC connector was not making real good contact on the center pin. A little bit of squeeze solved it.? You doing OK? Haven't seen you on 20m Olivia in a while.
Phil
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Jindra,
At the moment the QMX will not work with fldigi. There is an issue that was created when firmware 007 was released that prevents it from working. Hans is aware of this and hopes to resolve it.
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Hello,
is there a known setup for RTTY using fldigi and VARA setup?
I have had success with JS8Call, although TX signal required unusually high level setting (around -1? to -2 dB, while with TS-590S or G90 it was somewhere in the range -17 dB or lower) - but I suppose the higher the input level the lower the risk of including unwanted noise in the transmitted signal).
However, with VARA and FLdigi I had no TX output. FLdigi uses flrig to control the transceiver (which is perfectly OK), when I switch to TX it seems QMX is switched, too (sound in headphones disappear) but there is no output even when I set transmit level to 0 dB.
Is there anything else I need to pay attention to?
73 Jindra OK4RM
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Check the thread started by Hans-Wilhem on 12-27-2023.
Andrew,
Check the mux bias voltage at the junction of R401, R402 and C406. It should be close to 2.5 volts. If it is significantly different, it is highly likely that IC402 has been damaged while the TX was being tested.
The mux may have fallen victim to a problem with the T/R switch, for which a diode mod has been proposed.
That mod has been discussed in this thread and in a referenced thread. If you need to go that route, install the diode before replacing IC402 and powering up again.
JZ KJ4A?
On Tue, Jan 2, 2024, 7:15?AM M1CJE < andrew@...> wrote: Hi, Looking for troubleshooting suggestions/help please.
I have built the QMX and all is working fine except there is no received signal.? The audio stages appear ok as I can hear my own signal and the volume control works properly.? Tx on 12v is around the 4 watt mark.? The audio filter diagnostic tests show levels around -80 to -100 on all bands. The RF filter and Image sweep tests show similar levels.
The build manual says I should have a connection between pin 7 of IC402 and the L401 windings but this is not there so could this be the problem, but looking at the drawings I can't find the traces and on the schematic it is shown as not connected.? The other connections all test ok.
Any helpful suggestions appreciated.
73, Andrew - M1CJE
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My qmx got out to a park yesterday too.? Made a bunch of cw contacts on 20 all across the us.? A buddy brought along an ATU-10 which worked great with it.? I didn't hear cw clicking that other folks are reporting but I'm also using a very crappy speaker that produces a bunch of undesirable noise so maybe it is but I don't notice. Bigger problem for me is it regularly added extra dits (or was it dahs, don't remember) and I'd have to make a bunch of corrections. It was aggravating but not so much I didn't want to keep at it, still a fun easy to use rig.?
I also hooked it up to a pi zero 2 running digipi.? Was unsuccessful getting ft8 contacts in the logs, but for digipi reasons unrelated to the qmx. One thing I found odd was the audio setup was much different than what I was expecting, audio device names didn't match what was in the manual. I played with it and found a combination that worked but audio out was tricky. Not by it now to get a screenshot but maybe will soon.?
73, Jason KO4NDP?
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Andrew,
Check the mux bias voltage at the junction of R401, R402 and C406. It should be close to 2.5 volts. If it is significantly different, it is highly likely that IC402 has been damaged while the TX was being tested.
The mux may have fallen victim to a problem with the T/R switch, for which a diode mod has been proposed.
That mod has been discussed in this thread and in a referenced thread. If you need to go that route, install the diode before replacing IC402 and powering up again.
JZ KJ4A?
On Tue, Jan 2, 2024, 7:15?AM M1CJE < andrew@...> wrote: Hi, Looking for troubleshooting suggestions/help please.
I have built the QMX and all is working fine except there is no received signal.? The audio stages appear ok as I can hear my own signal and the volume control works properly.? Tx on 12v is around the 4 watt mark.? The audio filter diagnostic tests show levels around -80 to -100 on all bands. The RF filter and Image sweep tests show similar levels.
The build manual says I should have a connection between pin 7 of IC402 and the L401 windings but this is not there so could this be the problem, but looking at the drawings I can't find the traces and on the schematic it is shown as not connected.? The other connections all test ok.
Any helpful suggestions appreciated.
73, Andrew - M1CJE
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Re: QMX HI Band Rev 2. Immediate current limit on startup
An alternative to a milliohm meter is to carefully unsolder and lift individual pins on ICs that connect to VDD. ?When the short goes away, you have your culprit. ?This is tedious and not easy. ?I use a drop of low temp solder on the pin then carefully lift with a tiny thin blade. ?Wear eye protection though!
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Hi Andrew,
I think this mistake was due to some changes in this sections of the circuit between Rev 1 and Rev 2. Now pin 9 of IC402 is connected to T401.
vy 73 de Klaus, DG8RCN
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I believe the pin 7 of IC402 mistake is actually supposed to be pin 9 of IC402.? It has been corrected in the latest versions of the manual.
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73, N4TVC, Randy
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Hi, Looking for troubleshooting suggestions/help please.
I have built the QMX and all is working fine except there is no received signal.? The audio stages appear ok as I can hear my own signal and the volume control works properly.? Tx on 12v is around the 4 watt mark.? The audio filter diagnostic tests show levels around -80 to -100 on all bands. The RF filter and Image sweep tests show similar levels.
The build manual says I should have a connection between pin 7 of IC402 and the L401 windings but this is not there so could this be the problem, but looking at the drawings I can't find the traces and on the schematic it is shown as not connected.? The other connections all test ok.
Any helpful suggestions appreciated.
73, Andrew - M1CJE
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VARA cannot work with the QMX as it is not one tone at a time. RTTY should be OK.
Gary
W9TD
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Re: QDX Rev 5 High Band Internal Noise
Hey Cliff,
I had an early problem with this way back when I first got the QDX. In my case it turned out that the BNC connector was not making real good contact on the center pin. A little bit of squeeze solved it.?
You doing OK? Haven't seen you on 20m Olivia in a while.
Phil
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C525 is a thru hole ceramic capacitor part. Digikey should have them.
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Hello Razvan
On QCX if you wish to change the center frequency you must do so with hardware component changes since it is analog. You can also change in the configuration menu, the CW offset to match the new center frequency.?
On QMX the filter is not currently adjustable either (though it will be in future firmware updates); currently you are able to change the sidetone frequency and the CW offset frequency in the menu. You can choose a CW offset frequency between 600-900Hz. This will still be inside the 300Hz bandwidth?CW filter of QMX currently.?
On Mon, Jan 1, 2024 at 9:41?PM DL2ARL < dl2arl@...> wrote: On Mon, Jan 1, 2024 at 05:20 AM, Hans Summers wrote:
Which is normal because QMX uses DSP filtering.
?
...is it possible to set the center frequency for either of the QxXes?
Happy New Year to all of you!
73 de Razvan dl2arl
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Thanks!!! On Sat, Dec 30, 2023, 4:22?AM Philip Green G0ELM via <philip.r.green= [email protected]> wrote:
Hi,
Looking at the rev1 parts list all those filter capacitors are stated as 50v ?ceramic 0603 size, can usually get them with 1% tolerance and dielectric COG/NPO. They are not tantalum, they are used for higher values and are polarised for power supply decoupling .
Phil G0ELM
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Re: QMX 10-20m LPF0 problem?
Hi Jo! My QMX high band had initially also around 3W output which I found a bit meagre. I tried LPF1 and then I had too much output to feel safe (I think it was 6.7W). I went back to LPF0 and fiddled a bit with compressing and separating the windings of the toroids and got a bit more power. I found that separating the winding was the way to go and then I realized that maybe I should remove one turn on each toroid. I did so and noted that this was worse. Back to the original numbers of turns and a bit more fiddling, and after a while I was able to get 3.9W which I found decent. So I stopped. In the real world the difference between 3.0W and 3.9W is very small but this is a hobby where you kill time in a pleasant way. Try to compress and separate the windings. I don't think there is anything wrong with your setup other than that the tolerances of your components may play you a game.
Another thing I did was to replace the CB-band with 30M and run it through LPF0. I got 3W output on 30M and the current consumption looks fine. I was happy about that. I don't know how much of unwanted overtones that passes through the filter, and right now I don't really care. I may check that later some time. Maybe someone knows how good the LPF0 cut for 20M works on 30M...? And if there are other implications to ponder about when adding 30M like that.
Good luck, Jo!
Anders
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I've been catching up on my YouTube videos and just published a September POTA activation using my QMX and a modified PAC-12 antenna. I also used a KN4YB bug, which was a little scratchy at first. Not my best bug work, but the rig performed fantastically with one DX contact on an otherwise difficult propagation day. The QSB was very deep!
If you are learning CW, be sure to toggle the CC button to see the decoded CW.
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72/73 de Steve, K9NUD
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Juan
Randy, N4TVC
M1CJE
Gary W9TD
Chuck ke9uw
K9NUD-Steve