Re: QMX SWR measurement is not correct while using with PA
Plenty of PA's have inputs nowhere close to? 50 ohms resistive.? ? ?What does the nanovna see looking into the PA ( for interest as impedance will likely change markedly? with input power level )
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SSB Cal problems with QMX (not +)
I have been running firmware 1_02_000 on my QMX+ with good results on CW and SSB (haven't tried Digi yet) since the release of that firmware. So yesterday, I updated my original QMX with 1_02. The update went fine, and operation on CW was great, but I can't get all the SSB calibration procedures to look right. This is an 80, 60, 40, 30, 20 QMX, built for 12v (same voltage as my QMX+).?
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The cals failed to complete on 80, 60, and 30. On 80 and 30, I get an error message saying "Change over 30 degrees" from the phase error cal and it stops at about dac=~1100 to 1300. I got a similar error on 60m, but this cal ran successfully on 3 subsequent runs.?
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On the USB IMD sync, the final table in the upper right says 80m:15, 60m:74, 40m:23, 30m:62, 20m:26. In addition, 80m and 40m responses were almost flat - 80m ~140, 40m~100.
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On the LSB IMD sync, the final table in the upper right says 80m:74, 60m:74, 40m:29, 30m:15, 20m:26. In addition, 40m and 30m were almost flat - 40m ~280, 20m ~ 250. Also, for whatever reason, the y-axis max on 80m was ~7000000, and the y-axis max on 60m was ~1000000, both 1000 times higher than all other bands.
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On the ADC I/Q tests, the curves looked about the right shape (compared to samples in the oper. manual), but the upper left and lower left numbers were not very symmetrical. ?
80m? 42183/-42067
60m? 52338/-52457
40m? 55808/-56412
30m? 53881/-54284
20m? 36459/-35947
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Mic test works fine.
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PA Mod test looks good.
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Diagnostics look good on all bands with the following RF outputs.
80m 4.0w
60m 4.3w
40m 4.4w
30m 3.7w
20m 5.4w
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All tests with dummy load with Diagnostics showing SWR around 1.1:1
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Any comments or suggestions are welcome.
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73,
Randy, KS4L
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I realized it. I hope he can provide me with one...
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Re: QMX receiver went deaf
Ludwig,
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Q508 was checked based on the values you gave and did not show any issues.? I did not check d516.? The failure may have occurred from severe rf feed back as right before failure I had qmx connected to a large ldmos amp and could hear feed back in the speaker and see it on the waterfall.? I will use better isolation next time I try that.? For now I will be doing js8 call and ssb both at qrp.
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Ryan?
KK6DZB?
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Re: QMX+ printed assembly manuals
I seldom print anything out these days. I keep all of my schematics and PDF manuals in the cloud, so I can access them anywhere with a laptop, phone or tablet. When building my QMX+ a few weeks ago, I just scrolled through the manual as I completed steps. I can zoom in/out, search for words or terms, etc.
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One of the best moves I've ever made was to put a dedicated laptop in what passes for my shop (one wall of my garage) on a raised stand above my grinder, so it's not occupying scarce bench space.? All of the resources of the web are right where I need them while working. Not sure of a part spec or pinout? It's a google search away. While working, I can listen to music or monitor the HF bands via my SDR server upstairs. If a wanted FT8/FT4 DX spot turns up (my smartwatch lets me know!) I may even work them remotely right at the bench, connecting to my station upstairs over VNC.
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Re: Dreaded dead transmit from SSB Calibration routine
On Tue, May 20, 2025 at 06:28 PM, Robert Dale wrote:
Yes, they¡¯re all ~3.0v
Robert,
this would be wrong. There are rectangular pulses with 0 V for low and 5 V for high and duty cycle 50 %. Your DMM should read the mean value of 2.5 V. If realy 3 V IC503 could be wrong. This could result in a wrong switching of the BS170.
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73 Ludwig
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Re: QMX SWR measurement is not correct while using with PA
Hi Sergey,
It all depends on the design of the PA. Normally you won't use SWR protection in your transceiver if a PA is attached and working. Only if the PA is in pass-tru mode it could make sense. Then the QMX SWR measurement should be the same as the direct antenna connected. If the PA is active, its input impedance should be close to net 50 Ohm, if it is properly designed. With such a PA attached and active, switch off the SWR protection. It makes no sense. If the PA has its own SWR protection, use this. Otherwise, you may add a Power/SWR meter between the PA and the antenna to get reliable SWR data.
Jakob
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Re: Dreaded dead transmit from SSB Calibration routine
Ludwig,
Yes, they¡¯re all ~3.0v
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Recently, I sent my Rev 1 QMX, which I had problems with? the right encoder, and not able to load the new firmware. Mr Moore, troubleshoot the radios, and fixed the issues he found, then did a complete test of all the features, and clean any possible cold solders, or spaltters of solder. Then provided a detail report of what he did, and parts that needed to be change. All of that for just a small donation.
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Thank you very much Mr Moore, and looking forward to have lots of fun with my improved QMX.
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Ed Cortes
K4BQN
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WAIT.. . You have to get a new cpu from Hans.? It has a special Bootloader in its prom.
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Hello Ludwig and Michael,
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I followed your advice; IC503 is OK. After testing several ICs, I decided to unsolder the CPU, and now I have no shortcuts between VDD and VSS on the board. The CPU was broken. I will try to solder a new one.
Thank you for your help,
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74, Nico F5MDY
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Re: QMX receiver went deaf
On Tue, May 20, 2025 at 03:53 PM, Ryan Wesolowski wrote:
The basic trouble shooting you have written should go in the wiki especially the voltage values that should be seen at ic402 and ic403.
Ryan, good to know your QMX is back.
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Yes, that's my plan to put more information for debugging in the Wiki. Some steps are done. It's a question of time and energy to write more.
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Did you check Q508 and D516? In case of not enough isolation to much rf from the TX may go to the RX. See. A not working or not connected D516 would be bad.
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73 Ludwig
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Re: Dreaded dead transmit from SSB Calibration routine
Hmm, I haven't tried this yet, the only dummy load I have is a bird termaline 5w, wondering if that's up to the job?
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Re: QMX receiver went deaf
Ludwig,
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Replacing ic402 and ic403 has corrected the issue.? The receiver is no longer deaf and passed all hardware tests.? Thank you for the help.? The basic trouble shooting you have written should go in the wiki especially the voltage values that should be seen at ic402 and ic403.? Now I wish I know what caused the failure as I don't want to replace them again.??
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Ryan
KK6DZB?
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Re: U3S andLPF Relay Sw board
You just cycle through the menu hitting the <Menu> button without hitting the <Edit> button will show you each setting in order.
There are 2 possibilities:
?? FRAME
?? TxS => TX windows to show
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?? If you enable multiple TX windows, but your FRAME is too short, it cannot cycle through them.? I think this causes an error as well.
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?? Do you have enough "windows" set?
?? This screen defined the windows
XW x2 Tn Iv TxS
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0???? 0??? 0?? 0?? 11
The 11 means I can enable 11 windows (or Band settings).??
I am transmitting on 6 bands, but I place and RX between each TX even though I don't have any RX modules.? There is no need to place an RX after the last one as my FRAME setting will set the time before the next TX window.
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Also, make sure any #J window setting does NOT have lines through them.? That means the setting is disabled,
I have never tried forcing a TX, so can't speak to that.
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Rob KB8RCO
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Re: QMX+ printed assembly manuals
I printed it in black and white only. When in doubt I checked the colour photos on screen, enlarging them if needed.
20 May 2025 Sal 15:17 tarihinde Richard Dyer via <rdyer39= [email protected]> ?unu yazd?:
Me? Printed and 3-Ring Binder with tabs for assembly/testing and users manuals.?
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Re: QMX+ printed assembly manuals
Me? Printed and 3-Ring Binder with tabs for assembly/testing and users manuals.?
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Re: QMX+ printed assembly manuals
I do not print the whole manual. I do print the parts list for a check off list to verify all the correct components are present before construction. Using that list in conjunction with the components layed out in order helps.?
Steve
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Yannig,
If You have issues reaching the limit for free shipping from Digikey(and mouser), I usually add some Fair-rite ferrites to the order as they tend to find use :-) I recommend this one for portable current baluns:??.? 7?+ 7 turns of RG-316 or as many of RG58 that You can fit work fine for dipoles.? (maybe also include some BS170, BSS123 for spares :-) ) ??
Hi Mehmet,
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I am sure that it helps but I am trying to minimise the number of potential points of failure as I sometimes operate portable. Aborting an outing because I forgot to check the microphone battery (I can see myself doing this :-o ) would be a disappointment so I will try to find an electret microphone better than what I have now!
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I started with the Baofeng one, it was useless, then one from the local shop, it kind of work if you don't mind shouting and turns the AGC off, and now I think that I will mail order one with a proper tech spec!!!
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73,
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Yannig - F4IUJ
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The qrp guys microphone works very well. Sometimes I have to repeat my callsign several times and? e like echo is sometimes like x-ray ..lol. But ist works and I could make some SSB QSOs.
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73. de Matt, DL1SER
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Bruce Akhurst
Randy
Lawrence KC6WOG
G7TOK
Richard Dyer