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Re: Blocking a band on QMX/QMX+
Ah! Great info. Thanks a lot. 15 Oca 2025 ?ar 05:58 tarihinde Stan Dye via <standye=[email protected]> ?unu yazd?:
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Re: Blocking a band on QMX/QMX+
Nope. It is configured for 160-6 but there are no values listed in the manual under Putty's Band Configuration menu, except for 5 bands. Seeing the post on how to block certain bands, I am concerned my rig will not work on the unlisted bands. 15 Oca 2025 ?ar 05:07 tarihinde Ronald Taylor via <wa7gil=[email protected]> ?unu yazd?:
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Re: Blocking a band on QMX/QMX+
Bekir, it sounds like you may have your radio configured as an 80-20 meter QMX instead of as a 160-6 meter QMX+.? Ron On Tue, Jan 14, 2025 at 19:01 ta2rx bekir via <ta2rx.bekir=[email protected]> wrote:
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Re: QMX+ over-voltqge?
After the initial fifteen seconds of 13.8 volts, I switched to 12 volts. Maybe I should try 9 volts.
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Dave K9SW On Jan 14, 2025, at 5:49?PM, Chuck Harris via groups.io <cfharris@...> wrote: |
Re: Blocking a band on QMX/QMX+
I want to do the exact opposite of this. I want to be able to use my QMX+ on all bands, especially the upper bands. However there are no values listed for bands higher than 20m in the Band Configuration menu. That is why I asked what the ideal values should be on 6, 10 and 15m but could not get any answer so far. 73! de Bekir TA2RX 14 Oca 2025 Sal 18:05 tarihinde Bill via <bill=[email protected]> ?unu yazd?:
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Re: Problem with 50 Watt amp for QCX
Bernie Poskus, KF0QS via groups.io <hamdan@...> wrote:
The current draw measurement is 74 MA.? Unfortunately, the current drawNever turn it fully clockwise. If there was an intermittent connection and it accidentally went away, you'd destroy the finals. What is the voltage at the output of the linear regulator (78L05) when amplifier is keyed (but not transmitting)? |
Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)
Adam via groups.io <qrp-labs@...> wrote:
I'll order 5351, hopefully I'll be able to solder it without damagingHere's a follow-up. I ordered SI5351A, this one: It wasn't easy to replace, but I managed to do it without causing any damage. The radio works like new. No buzzing, good reception. It might be worth adding this info to some FAQ, or at least to: in case someone has a similar problem in the future -- which is possible, as I didn't stress the radio, it seems the chip failed on its own. Thanks again for pointing me in the right direction with false readings of my scope! 73, Adam |
Re: QMX+ over-voltqge?
Have you tried 12.0V?
-Chuck Harris, WA3UQV On Tue, 14 Jan 2025 16:54:49 -0600 "K9SW via groups.io" <K9SW@...> wrote: Thanks, Chuck. I’ve tried many variations, factory reset, restarts, |
Problem with 50 Watt amp for QCX
Dear Folks:
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I have finished building the 50 watt amplifier kit for the QCX.? I am trying to run the test on page 66 of the manual which simply requires you to do the following:
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1)? Make sure that the R5 potentiometer is fully counterclockwise.?
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2)? Put the QCX in "Practice" mode so no RF is generated, but the radio will generate a voltage to key the amplifier.
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3)? After keying the amp via the QCX, measure the current draw between the amp and its power supply.
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4)? Once you have keyed the amplifier via the QCX and measured the amp's current draw, R5 is gradually adjusted clockwise until the current draw begins to rise.? Once you see the current draw rise, you turn R5 back to the level just below the point at which the current draw rises.? That is the correct setting for R5.
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I have done all of these procedures.? I should mention that the green "on" light comes on when power is supplied to the amp and that the red TX light comes on when I key the QCX.? The current draw measurement is 74 MA.? Unfortunately, the current draw never changes even when I turn R5 fully clockwise.
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I should mention that I did try the same measurement with the QCX practice mode turned off, i.e., the QCX would now be generating RF.? At that point I found that turning R5 gradually changed the current draw from about 97 MA to about 103 MA.? However, no RF is generated (though the QCX generates about 4 watts when it runs barefoot).? This makes me think that R5 is functional.
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Does anyone have any suggestions for locating the problem?
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Thanks and 73 de Bernie, KF0QS |
Re: QMX+ over-voltqge?
Thanks, Chuck. I’ve tried many variations, factory reset, restarts, using SWR meter and dummy load, so no high SWR concerns. Still no output or input. I’ll work on it some more and see what else happens.
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It came from Mugla with the sheet listing all the power outputs on each band, so it was transmitting at one time. 73, Dave On Jan 14, 2025, at 6:37?AM, Chuck Harris via groups.io <cfharris@...> wrote: |
Re: QMX+ reliability
Mike,
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plus: in a big forum like this one, you mainly hear the squeaky wheels ;) And in most cases, the squeakiness is due to builders' mistakes (admittedly, modulo the few mysterious PCM1804 failures, as pointed out earlier).
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The QMX+ is an excellent, unique rig.
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My2Cents
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72/73 de M0KTZ
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
Thanks Don,
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This is new information to me. I did not look beyond the red and black pairs. I did think about color coded wires. I am using 14 gage red and black wire. Those other combinations would help.
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In this list of messages is a fresh new assertion that the QMX will absolutely puke with more than 12.0 volts applied. Maybe some day I will change my mind but for today I will avoid any "12 volt" radio that puny.
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Onward with the QCX and other tough radios.
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73,
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Bill ?KU8H
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Re: Best QMX AGC settings?
BTW here's a good thread on the subject: /g/QRPLabs/message/121907
I'm still searching for the perfect AGC settings lol. |
Re: QCX+ Build Problems
How much current is flowing on the 12v line? If very little then maybe the regulator?is bad. If a lot of current is flowing and the regulator is getting hot, then there is a short on the 5v line. Please verify which is the case. Also look at the soldering on the pins of the regulator On Tue, Jan 14, 2025 at 12:52?PM Martin AC1LL via <mshell52=[email protected]> wrote:
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