Re: Low Band QMX Spectrum analyzer measurments
On Thu, Feb 29, 2024 at 08:20 PM, Ronald Taylor wrote:
Chris, you technically don't meet the -43 dBc requirement
Yes he does. You clearly didn't bother reading his non US callsign which is quite clearly written at the end of his post. HINT - next time try reading the UK regs instead, there are no requirements other than making sure your tx doesn't cause undue intereference to others. Technically speaking, he can have a harmonic greater than a fundamental, and if it's not causing "undue intererence" then no rules are broken. OK, so that's an extreme example, but true. Reality is diferent, and most ops will take pride in suppressing unwanted emissions so that they don't cause problems. However, the point here is that many of us get just a bit pissed off with posts that assume the world has the same US rules. Now leave the rest of us alone to enjoy OUR regs, not yours. -- - 73 de Andy -
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Re: Older model QCX LCD lights up , but no display
The Backlight only need '12v' power applied to come on.
Most of the set runs on 5v via a regulator - but not the final few Audio OP amps which will generate some hiss..
Perhaps you ruined the first CPU (the instructions are too brief !) but the current one should have been fine.? ? I would proceed as the troubleshooting guide
in?
and?
Do all the DC checks in the build manual but start with is the 5V power there and at 5V !
?
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Re: Older model QCX LCD lights up , but no display
Next you should probably check for continuity on all pins between IC2 and the LCD. Those are :
IC2 ? ? ? ?LCD 2 ? ? ? ? ? ?11 3 ? ? ? ? ? ?12 4 ? ? ? ? ? ?13 5 ? ? ? ? ? ?14 6 ? ? ? ? ? ? ?6 27 ? ? ? ? ? ?4
73...Ron ?
On Sat, Mar 2, 2024 at 1:33?PM Kevin Welna < kwelna@...> wrote: OK, there is more to this story.? This was a functioning QCX,? but it had firmware version 1.00g.? I in my infinite wisdom decided to upgrade the firmware my self rather than just buy the chip.......oops LOL
I get all the cables, down load the software plug it all in and press the button..... I believe I should have not been powering the radio when I pushed the button.....Anyway, afterwards,? the chip did not update and the screen,? while it lights up still displays nothing.? I have since ordered a new chip.? Which has been delivered and installed.? Alas, the same issue? is still present,? The display lights up (Backlight?) but nothing is displayed.? Regardless of the contrast adjustment. ?? When I plug in my earphones I do hear hiss,? so I think? it is receiving?? but I do not hear anything but hiss.? since I can not see to tune the radio I am not sure that it is actually receiving....Any suggestions?? I did check pin 3 and the pot does adjust the contrast between 0 and 5V.
Thoughts on where should I look?
Kevin - W5LNA
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Re: #qmx high band harmonics
#qmx
On Fri, Mar 1, 2024 at 05:08 PM, Eric W. Hansen wrote:
What isn't clear to me, from the tinySA Ultra specifications, is whether its "recommended input power below -25dBm" is before or after the SA's built-in attenuator.? How do you read it?
Tiny SA also has a 20db LNA. If you accidentally leave it it on then you'd exceed the input spec, so -25dbm should be your final target just in case. ? -- - 73 de Andy -
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Re: RF preamp for power amp - HF and 6 mtrs. Magic silicon does all.
Questions / statements on this design.
First one is how the? drafter of the schematic - not the original designer came to? his Av? results
For instance the? input transformer has a voltage gain of? 2 and? a power gain of slightly less than one.
so as a? log ratio surely the? voltage gain is? +3 dbB ? But he uses? 20 log? V2/ V1 type formula I guess and he's getting? 6 dB
THe reason this is intriguing? is I want to see where his? Av of? 13.4 for the first video op amp comes from.
I 'd say that? the way to analyse this is? to replace teh 180 R feed back resistor with two 90Rs and a? virtual tap to GND.? That's because
it is a fully balanced circuit.??
So Av would? be? 332 /90? ? +1, using the std form for an inverting in put? FB amplifier.? THis gives a voltage gain of 4.7
I we use the Incorrect formula of? ? 20 Log? 4.7? ?we get 13.4? as a the? Av as a logarithmic gain. This aligns with his table.
This query is more about? the correct way of analysing the? performance of the RF amp than picking holes in whatever formulation he?
used for the? logarithmic voltage gain.??
any comments. ?
The other comment which I wills save is those ballasting resistors on the output? - they seem to be required as per the TI? datasheet for this chip.
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Re: High Band QDX One-Band-Low-Power Syndrome (yet again)
Hi William,
The RF sweeps combine the LPF and the BPF (L12 and one of the selected capacitors).? The most impact is from the BPF.? If the LPF is correctly built, it will be significantly above the operating frequency.? With that said, I do not use the RF sweeps to tune the LPF.? That is done by compressing or expanding the turns on the two toroid inductors in the filters.? Both can impact the output power, though, for me, the most impact was with the L2, L3, or L4 toroids.
Hans has a video on tuning a QCX LPF that can apply to the QDX.? The QCX has more toroids, but the principle is the same.
73
Evan
AC9TU
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QMX and QCX-mini repair - Jeff W1NC
Thanks to Jeff, W1NC for the great job repairing my builds of both kits.? I didn't believe the quick turnaround and how reasonable the cost was.? He will even throw in a tactful appraisal of your kit building skills :-) along with his frequent detailed communications.?
73
Reed AA1RB
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Older model QCX LCD lights up , but no display
OK, there is more to this story.? This was a functioning QCX,? but it had firmware version 1.00g.? I in my infinite wisdom decided to upgrade the firmware my self rather than just buy the chip.......oops LOL
I get all the cables, down load the software plug it all in and press the button..... I believe I should have not been powering the radio when I pushed the button.....Anyway, afterwards,? the chip did not update and the screen,? while it lights up still displays nothing.? I have since ordered a new chip.? Which has been delivered and installed.? Alas, the same issue? is still present,? The display lights up (Backlight?) but nothing is displayed.? Regardless of the contrast adjustment. ?? When I plug in my earphones I do hear hiss,? so I think? it is receiving?? but I do not hear anything but hiss.? since I can not see to tune the radio I am not sure that it is actually receiving....Any suggestions?? I did check pin 3 and the pot does adjust the contrast between 0 and 5V.
Thoughts on where should I look?
Kevin - W5LNA
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Re: Brainstorm question: How to "view" QDX LED status remotely?
Hi!
Apologies for inexperience and eye sight too bad to read all these messages...??
Brainstorms-- 1. Optocoupler with a long USB cable??
2. Smoke alarm?? <grin>
73 Paul KY4XJ
On Wednesday, February 28th, 2024 at 8:41 AM, natereik via groups.io <natereik@...> wrote:
My QDX is generally "remote" in my attic at my main QTH, running off a laptop up there, 30 feet feet from where I'll sit and "operate." I like the QDX for remote digital work, because there's no audio routing involved, no other software needed to operate, and I don't need huge bandwidth if I remote desktop in.?
BUT, I have run into situations at home where I've accidentally bumped a slider in WJST-X....and eventually figured out I wasn't transmitting even though WJST-X seems to show that I am. I go up to the attic and then can see the LED status indicator and realize there's something wrong with the audio.?
? ? ?I'm looking at putting 2 or 3 QDXs to the same computer at my 2nd QTH eventually, and have realized this could be an occasional issue there, as I'll want to remote operate from home. From what I can tell, there's no way through Putty or any other native way to "see" the status LED (or read the status) via a computer... I have low bandwidth at my cabin, upload speed is slow there (600 kbps), so a camera with video is out of the question. So I'm curious as to how you think one could most easily "remote view" the status LED on a QDX or 2 without an insane amount of complexity??
Phototransistors into Arduino inputs? Somehow monitor the current of the LED, but fast enough to see what it's doing? (as in, need the resolution and speed to "Read" flashes vs the 1hz sine wave, etc) Of course this isn't an everyday need, so if it's just ridiculous to do so, I'll skip it. But was thinking there may be a simpler way than what I'm coming up with.?
Curious as to what others think, as this is not an area of my expertise.?
-Nate
N8BTR
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High Band QDX One-Band-Low-Power Syndrome (yet again)
I am researching a low-power-on-one-band symptom on my High Band QDX, Succinctly, the power out was measured into a dummy load via a WM-2 and the rig was powered with a 5AH SLA bucked down to 12.0 VDC. Results below:
??? 20m ~6.0W 0.70A
??? 17m? 5.0W 0.66A
??? 15m ~6.0W 0.74A
??? 12m ~4.3W 0.66A
??? 10m? 2.0W 0.59A
I then did an RF filter sweep of the rig using PuTTY and got the images attached below. Here are my questions:
(1) I checked and compressed and loosened the turns on L4 and L10 to little or no effect on the sweep of 11m or 10m.
(2) To me, 20m looks like crap yet the rig puts out a healthy >5W on that band.
(3) The rest of them looks sort of OK.
(4) The 11M/10M looks great and clearly (to me) does not look like the LPF is causing the low power condition.?? ?
(5) Sorry for the ignorant question, but what do the filter sweeps show to all the trained eyes out there?
I have consulted the LY2H and EX0AA comments on the one-band-low-power matter and am still sorting through the group's anecdotal comments and other resources. Like LY2H, who could live with 3 watts on 10 meters, I could as well -- just not the one watt that my rig outputs on a 10m antenna. Also, I mainly want to get "some steerage" on how to utilize the tools and techniques to solve the problem.
Thanks in advance,??
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."
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Re: looking for non-US keyer chip
Hi, yesterday I ordered a keyer kit from HamGadgets. They actually had reasonable shipping, $17 compared to $30 to send only the chips. Everything seems to be included in the kit and it should take very litle time to assemble it. Ron VE8RT On Sat, 02 Mar 2024 07:51:57 -0800 "EA4HZK" <ea4hzk@...> wrote: Attiny85 chip very affordable anywhere and you can get the software from github.
--
__________________________
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------' .----------------. .----------------. .----------------. .----------------. .----------------. .----------------. | .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. | | | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | | | | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | | | | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | | | | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | | | | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | | | | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | | | | | || | | || | | || | | || | | || | | | | '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' | '----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
73's !
-- Ron VE8RT <ve8rt@...>
|
Re: looking for non-US keyer chip
Attiny85 chip very affordable anywhere and you can get the software from github. -- __________________________
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------' .----------------. .----------------. .----------------. .----------------. .----------------. .----------------. | .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. | | | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | | | | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | | | | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | | | | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | | | | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | | | | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | | | | | || | | || | | || | | || | | || | | | | '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' | '----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
?
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
?
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
?
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
?
.----------------. .----------------. .----------------. .----------------. .----------------. .----------------.
| .--------------. || .--------------. || .--------------. || .--------------. || .--------------. || .--------------. |
| | _________ | || | __ | || | _ _ | || | ____ ____ | || | ________ | || | ___ ____ | |
| | |_ ___ | | || | / \ | || | | | | | | || | |_ || _| | || | | __ _| | || | |_ ||_ _| | |
| | | |_ \_| | || | / /\ \ | || | | |__| |_ | || | | |__| | | || | |_/ / / | || | | |_/ / | |
| | | _| _ | || | / ____ \ | || | |____ _| | || | | __ | | || | .'.' _ | || | | __'. | |
| | _| |___/ | | || | _/ / \ \_ | || | _| |_ | || | _| | | |_ | || | _/ /__/ | | || | _| | \ \_ | |
| | |_________| | || ||____| |____|| || | |_____| | || | |____||____| | || | |________| | || | |____||____| | |
| | | || | | || | | || | | || | | || | | |
| '--------------' || '--------------' || '--------------' || '--------------' || '--------------' || '--------------' |
'----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
?
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
?
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
| _> | |/_ .|| | / / | \
|___>|_|_| |_| |_|_|/___||_\_\
?
___ ___ __ _ _ ____ _ __
| __>| . | /. | | | ||_ /| / /
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?
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73's !
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Re: QMX Using Z-Match ATU Blown Finals -- Twice
It's been mentioned many times in this group. I have a power cord with a buck converter to keep my 12V QMX fed with 11.5V.
Brian n1bs
On Sat, Mar 2, 2024 at 9:44?AM Howard Lamhut < Howardlam@...> wrote: I’m surprised more people haven’t mentioned this… But if your QMX is built for 12 V you should never apply more than 12 V.
If your QMX was built for 9 V you should never apply more than 9 V.
It’s fairly easy to damage your finals if you apply more power than 12 or 9 V depending on the build voltage.
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Re: QMX Using Z-Match ATU Blown Finals -- Twice
I’m surprised more people haven’t mentioned this… But if your QMX is built for 12 V you should never apply more than 12 V.
If your QMX was built for 9 V you should never apply more than 9 V.
It’s fairly easy to damage your finals if you apply more power than 12 or 9 V depending on the build voltage.
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Re: Another QMX Receive Issue Thread
OK! That's great news, Jason!? Congrats on the repair and VY 73 OM. JZ KJ4A?
Lo and behold, of course the back cover didn't fit thanks to the diode, I knew that but didn't remember when tacking it on.? So I took that off and put another on closer down at board level.? Since I was in there with the iron hot I reflowed the IC.? Cleaned it up, put it back together, and powered it up.? Sounds coming through again, nice and clean.? Yay, happy night.? Thanks for the advice John!
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Re: Another QMX Receive Issue Thread
Lo and behold, of course the back cover didn't fit thanks to the diode, I knew that but didn't remember when tacking it on.? So I took that off and put another on closer down at board level.? Since I was in there with the iron hot I reflowed the IC.? Cleaned it up, put it back together, and powered it up.? Sounds coming through again, nice and clean.? Yay, happy night.? Thanks for the advice John!
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Re: Another QMX Receive Issue Thread
John, got some ICs in and did the fix tonight.? If you wouldn't mind glancing over this and giving me some experienced feedback before I power it on again it'd be much appreciated.
Masked it off with some duct tape so hot air wouldn't affect much else.? Came off rather clean.? After this photo I added some flux and wicked a bit of the raised solder off.
Verified old to new and started tacking it on.? Looks decent from the top.
Until I get it around to about this angle and I see pin 1 especially is a little blobby but ok, nothing _looks_ touching.
But I go ahead with the diode which turned out good (imo).? But then I get another angle at the 1-8 pins and see it looks much different in that light.? Especially 1, 4, 8, and maybe 2.? Guessing it's worth going back and putting some more flux on and reflow.? Thoughts?
Thanks so much for your advice.
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Re: #qdxm QDX-M - new single-band version of QDX available
#qdxm
Hans Hi
Using 5 Volts (you can not blow anything :) ) from an USB and no LPFs no BPFs (bypass 7805)
I tested 2200m, 630m, 160m, 80m, 60m, 40m, 30m, 20m, 17m, 15m, 12m, 11m, 10m and 6m on transmit with the same QDX-M
all working (I transmitted less than 5 seconds each)
do not, repeat again do not try this with more than 5 Volts with no LPFs
you will definetely blow your Q6 and/or BS170s and/or IC5
73 DE muhsin TA1MHS
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Re: QMX Using Z-Match ATU Blown Finals -- Twice
--Ooops, the power meter was between the QMX and the Tuner
Chuck, W5USJ
EM22cv, Rains Co., Texas
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Re: QMX Using Z-Match ATU Blown Finals -- Twice
Evan,
I had Vcc at 9V this last time. I think the power with WM-2 and dummy load was about 1.2W
Next I switched to antenna with tuner in adjust mode. The bridge is about 1.5:1 SWR.
The failure happened when I switched to operate mode.
--
Chuck, W5USJ
EM22cv, Rains Co., Texas
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Bruce Akhurst
Ronald Taylor
Timothy Fidler
k6whp
Howard Lamhut
Chuck Carpenter