Great stuff Jerry, and good to take a look back when building was the norm!
Just a word on the touch keyer. I built it, because touch is what I had in the old times. With the QCX I found it to be quite temperamental depending on the antenna (RF I guess), so moved on to the pressure paddle.
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73, Peter
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Go down 7 photos here, Wes working his Micro-mountaineer is the small black and white photo to the right:
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His QST article describing the Micro-mountaineer starts on page 11:
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Built it shortly after that was published in 1973.
Laid out and etched my own board with ferric cloride.
A step up from them Pixie thingies on ebay today.
Lots of plans for it, but made perhaps 2 contacts.
Climbed Mt Hood, but didn't bother taking the Micro-mountaineer.
It's in a box somewhere down in the basement.
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Also in that issue:? the WB4VVF Accu-Keyer.
Built that too, I think it's down there in the same box.
After 40 years as a digital design engineer I took another look
at the schematic, still can't figure out how all of it works.
A very elegant design, but uses some nasty tricks.
Set the standard for decades to come on how a keyer should behave.
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Another article in that issue was the third installment of W2DU's
"Another Look at Reflections".? That I did figure out a few years ago
but it was some very tough sledding.? He had some nice insights?
into how transmission lines work, but no idea how to write.
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I just bought some AT42QT1011's so I can add M0UKD's touch keyer to my QMX
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Jerry, KE7ER
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On Fri, Feb 21, 2025 at 07:04 PM, Curt wb8yyy wrote:
Many years ago W7ZOI is pictured with a handheld cw rig. Key is attached, maybe battery in his pocket and a wire antenna is deployed into a tree. Certainly qmx can do this with a suitable key. I may have seen something pictured here recently.?
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Curt
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Many years ago W7ZOI is pictured with a handheld cw rig. Key is attached, maybe battery in his pocket and a wire antenna is deployed into a tree. Certainly qmx can do this with a suitable key. I may have seen something pictured here recently.?
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Curt
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Re: Linear voltage regulator for QMX+
I asked to QRPkits and they answered:
- this kit is basically a filtered and regulated power supply without the transformer. Input voltage up to DC or AC 20V. Output voltage from 1.25V minimum to maximum 3V below the input voltage.?
- a schematic might be added to the manual in the next update.
They gave me the attached schematic.
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With my three LiFePo batteries connected in series I would get a filtered and regulated voltage from 11.2V (full charge)? to 9.8V (full discharge) or a filtered and regulated 9V (from full charge to full discharge), which would be even better for a QMX+.
With my 5 to 12V-3A and 13.5V to 15V-2.4A Wall Wart set to 15V I would get a filtered regulated 12V-1.5A power supply, set to 12V I would get a fitered regulated 9V-1.5A power supply.
With a computer wall wart delivering 19.5V I would get either a filtered and regulated 12V or 9V.
And it costs 20 US$, I'll think to it if I build a QMX+, it could be inserted in a QRP-Labs "large blank enclosure" with a "dev kit", an AF amplifier and speaker and possibly a 10 W linear amplifier ()...
73 - Pierre - FK8IH
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If the filters are in the default setting and the sidetone frequency and cw offset are the same, even a tone-deaf op like me can match the other station without actually zero-beating a generated tone. At least close enough that i rarely lose the QSO. JS6TMW
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What firmware revision did you have when the rig failed like that?
What hardware revision?
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Latest firmware rev is 1-00-027, and seems to have reduced the occurrence of this sort of thing considerably.
If it still happens fairly often, then the power supplies may need to be looked at further.
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Jerry, KE7ER
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On Fri, Feb 21, 2025 at 02:04 PM, Kevin (KQ4DTX) wrote:
What I found was that my Zener diode D109 had shorted to ground.? ?
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On Feb 21, 2025, at 12:42?PM, ajparent1/kb1gmx via groups.io <kb1gmx@...> wrote:
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Elapsed time 3 days...
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--
Allison
------------------
Post online only,?
direct email will go to a bit bucket.
-- Jim / K7TXA
Eagle, ID
SKCC 10447T
BUG 301
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Re: QMX+ power & transmit current vs input voltage plots
I assume you wound T501 with the RWTST 3:2 turns ratio since you are running it at 12 volts.
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My opinion is you may show your numbers as long as you are within the QMX+ specifications as far as voltage goes. Be sure to confirm the accuracy of your measurement instruments. This should prove helpful to others.
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i could not see your plots either.
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Re: QMX+ power & transmit current vs input voltage plots
didn't see the plots but maybe i missed them?
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Hi all,
A quick comment about twisting the wires for the transformer: The twisting increases the coupling coefficient , k, between the windings. This reduces the leakage inductance (1-k), thereby improving efficiency of the transformer.
Milt w8nue
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On Feb 21, 2025, at 4:16?PM, va3rr via groups.io <va3rr@...> wrote:
?Karl;
There's a longish thread back when the high-band QDX was being built by many, but output power was not as high as many would like.
/g/QRPLabs/message/101412
Han's adopted the twisted winding method developed by EX0AA et al.
vy 72 de Russ, va3rr
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New Chat: QMX+ Audicity recording - please share!
#chat-notice
A new chat has been created:
Can you share your audicity recording from a QMX+ both with and without a signal with me?
By:
NQ5P <rjj100@...>
View/Join This Chat
Do not reply to this message to post to the chat. You can participate in chats only through the group's website.
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Re: Need pictures of QMX+ I&Q recordings & spectrum with and without signal
Correction - Audicity not audaucity
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Hi Yoon,
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Yes, besides erratic behaviors you described, the side tone also sounds funny.
Looks like to use reel wire to lower the SWR is the key. I could only get 1.8:1 from MFJ1720 as I remembered.?
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I will try on 10/12m again. If it works, it will be a good supplement to KH1.
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73
Wei AG6AQ
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Matti,
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? ?I was recently working on adjusting the toroid winding for power adjustment when my QMX+ display screen flickered quicky while handling it.? I look to see what may have caused it when I noticed my power connection was coming loose from the back of the unit.? ?After pushing the plug back into place, the QMX+ quickly powered off instantly.? ?
? After that the QMX would not power back on.? ?I tried everything under the sun to get the unit to boot back up.? ?NO GO.
?What I found was that my Zener diode D109 had shorted to ground.? ? I could test this theory by pressing the power on knob and holding my finger on either Q109 or Q111.? ?I am sorry but I forget which it was of the two transistors but anyway the transistor got instantly hot to the touch of my finger.? ?I then pulled one of the legs up on D109 to take the diode out of the circuit.? After doing so I attempted to power on the QMZX+ with 7v limited to 200ma.? ?What did you know, the QMX+ came back to life.? ??
? I repaired the unit by replacing the D109 Zener diode with a known good one.? ? (D109= Zener 3.6v 500mW)
? I think this may be the issue you may be chasing for why your unit is not responding to the power on button if I am following the event of how yours shut down.? ?
Also, I remember check that the resistance across VDD and Ground read something like 265 ohms.? ?It should be in the Kilo Ohms or higher.? ?You can begin there with checking with your ohm meter.? No power applied occurs.?
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P.S? ?
?I agree that for the no power out issue, double check that you added the jumper during your build.? ?Good Luck and hope this helps.
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Karl; There's a longish thread back when the high-band QDX was being built by many, but output power was not as high as many would like. /g/QRPLabs/message/101412Han's adopted the twisted winding method developed by EX0AA et al. vy 72 de Russ, va3rr
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On Fri, Feb 21, 2025 at 07:11 PM, Matti OH6BEX wrote:
But still, I do not understand how all this happened.
A full working equipment stops working by just pressing some buttons of the user interface.
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You applied pressure to the board.
Maybe caused something to short circuit.
Even under the board, you had it on the bench unmounted.
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73 Alan G4ZFQ
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On Fri, Feb 21, 2025 at 08:11 PM, Matti OH6BEX wrote:
But still, I do not understand how all this happened.
A full working equipment stops working by just pressing some buttons of the user interface.
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Matti, hard to say without more information. Maybe after getting some results from your tests.
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73 Ludwig
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Need pictures of QMX+ I&Q recordings & spectrum with and without signal
I know people post pictures sometimes, but I cannot see them.
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I vassilate on whether my QMX+ is working correctly or not. I have never received strong CW or FT8 signals, but they are there - but weak.
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i have made audaucity recordings (low levels) both with a signal and not, which I would like to compare with others but cannot see any on Groupsio.
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i have looked for a setting which enables seeing pictures but no joy. I am using an Apple Ipad.
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Help!
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Re: Linear voltage regulator for QMX+
Hi Gert,
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Note that a minimum voltage drop is required.? From the specs:
- Output adjustable from 1.25V to approximately 3V below the input voltage
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Three volts below 13.8 is 10.8 volts.? This would be the maximum output voltage regulated from a 13.8-volt supply.
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73
Evan
AC9TU
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On Fri, Feb 21, 2025 at 11:49 AM, Wei AG6AQ wrote:
I was inspired by your post and tried myself with MFJ1720, the major problem is RFI. Have you seen RFI problem in your handheld setting?
Wei, what was the symptom of the RFI problem? Maybe some erratic behaviors of QMX like turning off itself or the keyer suddenly not working, etc.?
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I do remember having that kind of problems when trying handheld operation with different whip antennas and certain lengths of counterpoise wire. I think the problem can be generally minimized with the lowest SWR you can achieve, although there are many other factors affecting the antenna match with HT operation - your hand, head, body and your posture, also the dry or wet ground where you stand on, etc.
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Then I found it very handy to use the reel wire as the counterpoise, with which you can easily find the best match in any circumstances, which will surely minimize the RFI problem. I haven't had the problem with my whip antenna and the reel counterpoise wire.
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73,
Yoon KM6KJI
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Peter HB9EBE
Pierre - FK8IH
va3rr