Meanwhile having some QCX mini, now also own a QMX. Unfortunately I experienced a mysterious issue while keying CW that I don't know from the QCX. Every once in a while the QMX keyer omits a dit or a dah. At first I thought of a contact problem of my morse key (BaMaTech) but on my WinKeyer it worked flawlessly. I tried several speeds but even at low speeds this issue was present. After some futher experimenting with some alternative configurations and with other morse keys I think this is a problem of the QMX. I have firmware 1_00_027.

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Any ideas?

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73 de Michael, DF9TZ

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Just put a common mode choke 10 feet from your rig in the antenna coax line. ?I have had RFI cause all kinds of strange interference with my experimenting with all my QRP rigs. ?I have found that a CMC at 10 feet has “cured” many strange problems I have had in the past 10 years.?

Thanks for the ideas so far.

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As I am used to Iambic A I also choose this option on the QMX.

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Incoming RF obviously is not the problem as this issue also occurs in practice mode. To be shure I tried a dummy and got the same result.

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Could it be that the processor is not fast enough by handling the paddle input? I found that the QMX occasionally even does not send single dits as for an 'e' letter. In one case after sending some text with medium speed (20) the QMX hang by sending a continuous tone so I had to switch off power.

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None of my QCX showed this behaviour at any time.

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I am puzzled...

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73 de Michael DF9TZ

I have the exact same issue with the cw keying on my QMX+.? I have changed all the variable parameters for the CW keyer to no avail, as it misses dits. I have resorted to using an external K1EL USB keyer, which, of course, works fine with no missing dots.? The key jack is set up for straight keying when using an external keyer.? It would seem that the auto keyer emulation in my radio is the culprit. I have a 9V version and run it using an external INIU Power Bank with a 9V PD cable.? A voltage sag could cause the problem, but it has not bothered me enough to consider looking into the real issue.

73's Joe K8FC

On Tue, Apr 15, 2025 at 06:12 AM, Michael wrote:

Could it be that the processor is not fast enough by handling the paddle input?

Highly unlikely.

I have heard many others report excellent keyer performance, even at higher rates.

And while I'm far from a CW expert, I have never noticed any malfunction of the keyer.

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So I'm wondering if your particular QMX has some internal issue, like a flaky jack or one of the components.? The dit line in particular is also shared with the mic input, and has an extra capacitor and resistors and the bias voltage for the mic.? If any of these is malfunctioning or 'noisy', it could cause a keyer problem.

Michael,

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I don't know if this is your issue, but if you have used any of the "Iambic A" keyers with anticipation, then you will lose dits/dahs, as the Iambic A mode in the QMX has no dit (or dah) pre-stored memory (except when you actually squeeze, that is).? Many keyers implement a logic whereby what they call the "Iambic A" mode does have a way to store an element while composing the inter-element space (i.e., while the inter-element space is being issued), so that you can release the dit/dah paddle while the space is being issued, and still get the extra element at the end. This capability is called 'anticipation" in some keyers, and is meant to make Iambic A "more responsive". It is a matter of milliseconds, but if your fingers are muscle-trained to do that routinely with a given keyer, you will notice the difference when you don't have anticipation.

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I have tried and used many different keyers, and can confirm that the QMX keyer does not have any specific issue. It just implements a pure Iambic A keying, with no pre-stored elements and no anticipation. This can make the keyer feel "tardy" when one comes from a keyer with anticipation, and this is something I notice when I come back to the QMX after having used another keyer. I have used the QMX up to more than 50wpm, both in Iambic A and in Iambic B, and it does not miss a dit, unless I do make a genuine keying mistake. It certainly does not miss dits at 20wpm. Provided that you don't expect it to "pre-store" your dits before the full inter-element space has been issued.

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I can confirm that RF in the shack can actually interfere with the QMX keyer, and that can be a source of all sorts of headaches. But RFin the shack also wrecked almost any other keyer I was using, before I solved the issue.

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Hope this helps

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72/73 de Enzo M0KTZ

Thanks a lot for your ideas, thanks Hans for your explanaition.

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Sometimes the easiest solution is the most likely. After some further experimenting I found that in fact it was a contact problem at the paddle jack. After fixing this, the keying now works as it should.

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Problem solved :-)

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73 de Michael DF9TZ

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