Hi Daniel
I would suggest? you run the U4B transmit program first for 30 minutes info in the manual? and then do the hardware test ...?
I would also suggest you put a 50 ohm resistor over the hf antenna pads while testing.
In some cases the hardware test is difficult to lock and it is aided by using a bit of tinfoil under a piece of paper? with the U4B on top of the paper so the gps antenna could work more effectively inside the house.. just use a simple dipole antenna for the gps with legs about 47mm and in a vee shape.
Dave VE3KCL
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Thanks Hans - all your hard work is much appreciated.
Beyond excited that mine has shipped (#72754)!
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Hi Larry,
Please review the following video.? It is for the QCX+, not the QMX.? The principle applies.? You what to try adjusting the LPF inductors to see if you can optimize the power out:
There is no class E amp in the QDX (the QDX is class D), so ignore the first part on adjusting L3.? The QMX uses 5 pole filters, so only two inductors can be adjusted.? The other point is that the LPF is shared for one or more bands.? You may have to choose between bands or find the middle power output.? The example is 20 and 30 Meters share the same LPF.? You can optimize for 20 or 30 or find the midpoint between the two.
73
Evan
AC9TU
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Thanks Dan and Colin, A lot of the experience for those of us who are building these rigs is learning and understanding them. Nice to have a group to work through the process.
73,
George, n9dxp
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Re: QMX Receive Optimizing--Navigating the QMX
Jack, arrow buttons to move between parameters, then delete or back space to erase, the type in correct value, then arrow buttons to next parameter. You have the BPFs and biases correct.?
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73, Dan? NM3A
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George,
?I have no idea as to why Battery Monitor makes a difference either. But I've been there with unexpected s/w glitches.?
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73, Dan? NM3A
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I am guessing that there is an interrupt that is not being serviced in a timely manner but having never seen the code, I can only guess. ?
--
Colin - K6JTH?
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I built my QMX for 9 volts.
After the L401 jumper mod I kept the original number of turns and spread them out as much as possible.?
The receive has improved but the transmit power is well below what the manual shows it should be.?
80M 4.0W 60M 4.1W not to bad but 40M 2.6W 30M 3.3W 20M 1.9W.?
I've recounted all the wrap counts on the transforms all for good. I've rechecked all soldier connections.
I also checked to be sure 20M pin was set to 30.?
Has anybody else having this problem???
I know there is a lot of firmware upgrades in the future but don't know if any of these issues are firmware related.
My test equipment is a old Fluke DVM.
Looking for thoughts and ideas.
TIA?
Larry NA0F
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Thanks Dan. Just wondering why having the battery monitor on or off makes a difference.
Thanks,
George, n9dxp?
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Very good Mike, that helps a lot. This is my first QRP Labs radio so I was a bit lost.
George, n9dxp
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Just a quick Q w/ KE8MOA on gud ol' forty.
QDX running ten milliwatts ( as usual for 40m ) to the end-fed wire.
Tnx QSO !
72.
Bill, N4QA
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Re: QMX Capacitor Swap Gives Lower Power.
#qmx
Ops, sorry Bob. I'm watching too many threads.?
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On Jul 14, 2023, at 17:22, Bob Finch < w9ya@...> wrote:
Not the problem as both Cliff and myself have the bias set at 30... On Fri, Jul 14, 2023 at 11:34 AM, Gary W9TD wrote:
I also have better power output on 20 with the cap swap. I think your problem lies with the PIN diode bias. The band configuration screen that Hans showed for mod #2, shows only 5mA PIN bias on 20. That is wrong, it should be 30mA like all the other bands.
Gary
W9TD
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QMX Receive Optimizing--Navigating the QMX
I've been following the discussions about improving the QMX receive sensitivity, and I have no problem admitting it's way beyond my comfort level.
My QMX is built, but I haven't put power to it yet. I plan to start with a 9v smoke detector battery. Still psyching myself up for that event.
As there is no user manual yet, I'm after some basic "how to" information for the QMX.
My QMX has L401 modified according to Option 2, (the build described in the latest edition of the assembly manual). That's 19 windings between the start and 30m holes, 9 windings between the 30m and 40m holes and the jumper between 40m and 80m holes.
QUESTION?? Are the windings (19 and 9) best configured spread or compressed?
I assume the Band Configuration Screen is accessible on the QMX via the function menu?
QUESTION?? Where do I find/how do I access the Band Configuration Screen?
At the Band Configuration Screen, I must change the BPF numbers as follows--20m to 1, 30m to 2, 40-60-80m to 3.? QUESTION?? How are these changes navigated on the Band Configuration Screen? Which button/knobs move the selector and which buttons/knobs change the numbers?
Still on the Band Configuration Screen, do I also need to verify the correct BIAS for each band?
QUESTION?? Should the correct BIAS for all 5 bands be set at 30?
So, am I in the right ballpark, or do all these settings need to be changed some other way or place?? Like through a computer program or via a screen somewhere in the firmware?? If so, can this be done on a Mac, or does it require a PC platform?
Many thanks. The build was a lot fun for me, but I get very stressed with computer stuff. It isn't at all intuitive for me and I'm afraid I'm going to mess something up
Many thanks.
Jack N8EU
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Re: QMX Capacitor Swap Gives Lower Power.
#qmx
Not the problem as both Cliff and myself have the bias set at 30...
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Show quoted text
On Fri, Jul 14, 2023 at 11:34 AM, Gary W9TD wrote:
I also have better power output on 20 with the cap swap. I think your problem lies with the PIN diode bias. The band configuration screen that Hans showed for mod #2, shows only 5mA PIN bias on 20. That is wrong, it should be 30mA like all the other bands.
Gary
W9TD
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Re: QMX Capacitor Swap Gives Lower Power.
#qmx
That wasn't me....that was Gary, W9TD
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On Fri, Jul 14, 2023 at 02:21 PM, Cliff wrote:
Yes, I was referring to your suggestion to check the forward bias setting.
On Jul 14, 2023, at 16:18, Bob Finch < w9ya@...> wrote:
If you are referring to me....bias is at 30.....
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As long as you have Tx/Rx param 2 set to 1, there should be no pops on keying. If you don't have Battery Monitor on, you shouldn't have any significant keying timing issues.?
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73, Dan? NM3A
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Re: A song of praise for Hans Summers
OMG!!!
c'mon
His Head is going to EXPLODE!
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Re: QMX Capacitor Swap Gives Lower Power.
#qmx
Yes, I was referring to your suggestion to check the forward bias setting.
toggle quoted message
Show quoted text
On Jul 14, 2023, at 16:18, Bob Finch < w9ya@...> wrote:
If you are referring to me....bias is at 30.....
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You need to connect through a serial tool. I use putty to connect to the rig via the usbc port. Then Band Configuration is one of the menu options there. It's not on the rig menu system. Perusing the QDX documentation will provide more details if needed.
-mike/w1mt
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Jacques,
Thank you for the clarification.?
73
Evan
AC9TU
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VE3KCL
ZL1SGS
Colin Kaminski