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That's an interesting one.

I'd start by checking the actual voltages, measuring using a separate meter.? Check the '+12V', VCC (5V) and VDD (3.3V) voltages at the different input voltages, You may find that they are considerably different to what is indicated by the QMX measurements.? AIUI the QMX ADC uses it's 3.3V supply as the reference for the ADC and if that's incorrect then all the other voltages will be reported incorrectly.? You may find that the 3.3V supply is low and that's why the others are high.

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Once you know what is going on you will have a better chance of fixing it.

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Chris, G5CTH

Hello again,

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I had the time to think about it further...

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I can't make my QMX do SSB, I was blaming the microphone but may be there is something else going on. Whenever I do SSB, it is very noisy thus I am thinking that may be the ADC are somehow compromised and the microcontroller can't regulate properly voltage nor properly sample the microphone output.

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What would you think, plausible ? How could I check this hypothesis ?

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73,

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Yannig - F4IUJ

SWR is calculated by measuring the forward and reverse voltages obtained from T507 and calculating the SWR from those.? It there's no power out then those values can still be measured, they will both be close to zero, with noise.? A 'SWR' value can be calculated but it's just done from two noise measurements which is why the value varies widely.? The power is derived from the forward value only.

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Chris. G5CTH

John?

I started seeing dead parrots :(

73 DE muhsin TA1MHS

Hello Daniel, I used a microphone from an old Panasonic phone. I don't have any information about it, but I tested it in the terminal and it had very good sensitivity and dynamic range.

73

On Sun, Apr 6, 2025 at 11:09 AM, Muhsin TA1MHS wrote:

Hi?
I found and using this
5/9/12 (15/20(for the PC) if the PD of the Power Bank Supports)
9 and 12 volts are great for the QDX, QMX and QMX+
Buy the one with 5.5 x 2.5mm plug


73 DE muhsin TA1MHS

If you look into this link,

You'll see 3 types of plugs.

Only 5.5 x 2.5mm plug works with QMX.

This is not what I think, It is what I and other people are using.

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What we know/read may not be the ultimate truth

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What a waste of time

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73 DE muhsin TA1MHS

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On Sun, Apr 6, 2025 at 04:02 PM, Paul - AI7JR wrote:

Hard to understand measuring SWR if you truely have 0 watts out... :-)

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Paul -- AI7JR

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That's why I mentioned it in my original post.? The SWR is reported in the Diagnostics page on the terminal when I hit T for Transmit.? For me, it's all over the map, sometimes reporting in the 6-7 range, sometimes so high it just reports ####, and other times dropping down to the 1-2 range.? All of that while it claims 0W output (and a wattmeter on the dummy load shows no power).

Thanks Stan. I never studied magnetics so I wasn't sure how well that little core would react. The wires are still connected and none of the windings have come undone. I'll try gluing it tomorrow.

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I saw that kit on Amazon and that's my Plan B.

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Thanks again!

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Dave

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Yes, it should work fine if you carefully glue it back together, as long as the wires are not broken.?

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And if you need a new ones, I have used the 330 ones from this Amazon kit:

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Stan KC7XE?

Two thumbs UP.

GREG

I had been trying to figure out why I could not make any ft8 qso's. Seemed wsjtx was connected, got audio in my ear when transmitting. Would change radio bands. Turns out I missed when reading the manual, make sure computer volume is set to 100%, and no more. Mine was at 150%. Working great now. It always seems to be something I did wrong. Hope this helps someone.

I think L403 is coming off the board tomorrow....

--

73
Karl
KI4ZUQ

I seem to have found my way into the Monty Python 'room for an argument'

Muhsin is correct.? As I noted in my original reply, some 2.5mm connectors may work.? Some are designed with spring contacts, and are advertised as being compatible with 2.1mm.? And those do achieve a good contact.?

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However, Muhsin, if there are two choices in a connector for a QMX trigger cable, and one of them is 5.5/2.1mm, as is the case with buying most brands of trigger cables, the correct and best choice is ALWAYS the 5.5/2.1mm connector.? It will provide better performance over the long term, and will avoid confusion with 2.5mm connectors which don't have spring connectors, and are dangerous for use with QMX/QMX+.

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Stan KC7XE?

On Sun, Apr 6, 2025 at 06:43 PM, <mitchellrlawrence@...> wrote:

I am going to start form the bnc and work my way back through the circuit unless I find any other advise?

Be aware that the VSWR transformer winding puts a DC (not RF) short across the output BNC connector.

73, Don N2VGU

Thanks Stan and John. I think that's what I probably did; changed the mode from WSPR to CW by mistake during transmission. I'll try again once I am out in another park soon.?

On Sun, Apr 6, 2025 at 11:48 PM, John Pokluda wrote:

oversized barrel

It is not a barrel, it is spring based, works with 2.1mm
73 DE muhsin TA1MHS

First check keyer menu and check your not in practice mode and then display and in CW mode.

This mistake I have made many times!