Re: W2LI Magnetic Loop Antenna - Anyone Use This?
I have a homebrew magnetic loop with a 10 foot coax outer loop that tunes 30m - 15m.?
I always (or at least usually) tune it with a nanoVNA before connecting my radio.? That way I can make sure the finals are protected, and I can also check to see what the 2:1 SWR bandwidth is so I know how far I can tune before adjusting the antenna.
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73,
Mike, KL7MJ
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Hi Luis -?
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I've used iFTX with my QMX using a USB-C to USB-C cable. Haven't made a video on it yet, but it works like a champ. Just requires setting a few threshold values correctly for Vox. Worth the $1.99 ;)
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73,
Mark
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There's no need to change to CW-R mode at all regardless of what band you are on. It's just a user preference.?
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73
de Roy - KI0ER
Littleton, Colorado USA
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Re: QMX (not-plus) power issue
Just some quick thoughts on your observations.
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RE: low watts out on 30/20.
They share the LPF pair.
Inspect solder joints, turns on the toroids, capacitors etc.
Fiddle with spreading and squeezing turns on those two as well.
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RE: power output differences
Have you tried different interconnect cables or BNC couplers?
Do you get the same results on the diagnostics with just the dummy load connected to the QMX? Try with both interconnect cables and/or BNC couplers.
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Any chance you have a nearby Ham Buddy that can check the new power meter. Or perhaps you have another radio you know works well?
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Hope it's something simple since the new power meter seems to be showing just about 1/2 of the expected power out?
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Re: qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
Lee - yes, that's exactly what I did. Anode to U101 on the top of the daughterboard, and Cathode to the 3.3 Volt VDD pin on the bottom side with a short wire.?
73; Steve, N3SB?
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-------- Original message -------- From: harleyleenuke <vfrank59@...> Date: 9/20/24 3:31 AM (GMT-05:00) Subject: Re: [QRPLabs] qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
I have the New PCB with the power supplies on the main board. I will inspect everything again.
?Steve where didyou make connection for the D103 ??
?I am thinking , mine on top of the PCB? IC101 output to a nearby VDD JP106 hole.
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I am unclear if that is correct,? ain't done it yet.
Lee,
?AA7HC
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Has anyone had experience with QMX + iFTX with the virtual USB port?
The costs that apply US$ 1.99 are annual or monthly, I can't find this thread on my iPhone
72 Luis
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Re: QMX practice mode suggestions
Hello Chelin, in digital modes it works in USB, I only do CW and my question is if I should change the mode to CW-R like I do on the K2, Ft817, Xiegu X6100 etc? Luis LU4HK - L73H
El vie, 20 sept 2024 a la(s) 9:36?a.m., Bob Parr via (parr= [email protected]) escribió: So it is just a way to allow the radio to function only without transmitting?? I see why that would be helpful for CW, but not so much for digital modes.
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Bob
KG5GTE
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Re: QMX practice mode suggestions
So it is just a way to allow the radio to function only without transmitting?? I see why that would be helpful for CW, but not so much for digital modes.
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Bob
KG5GTE
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Hello everyone !! I'm Luis LU4HK, and I have a question with my QMX 40-20.
When I use the 80-60 and 40 meter bands, I must change the configuration to CW-R or the mode is recognized by default.
72 Luis FF78lg
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Re: QMX (not-plus) power issue
On Thu, Sep 19, 2024 at 10:22 PM, Michael - WD0OM wrote:
with what look to be calibration screws under the needle display.
Those are usually mechanical meter zeroing adjustment screws, for zero setting, not calibration.
73, Don N2VGU
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Re: Solder iron tip recommendations
There is no one-size-fits-all answer, indeed, I have used 2 or 3 different irons/tips on a single board, depending upon the PCB involved.? Smaller pins/components with tighter spacing need a smaller, perhaps conical tip, whereas a larger, ground pin or TO-220 part may need a larger chisel type at a higher temperature.? You may need yet a third to solder large power conductors or RF connectors.?
I have 3 soldering stations and many different tips on my assembly bench and I have had them all in play on a single project.
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One thing which will help is the application of background heat to the board; it will make soldering much easier and is actually less stressful to chip components as the board and components cool and contract.? Even putting it onto a 100°C hot plate helps immensely.
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73, Don N2VGU
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Ultimate3S has started crashing during transmission.
We have a Ultimate3S running at the club and has been running with no problems for over a year. For some reason it will start it's transmission sequence and at the end of the first transmission it appears to crash and not finish. Firmware is still running after the crash and will attempt the transmission sequence again at the next half hour mark but will fail. It's configured to TX from 10m down to 80m (10, 15, 20, 40, 80 starting on the half hour. Some will start the sequence and fail part way through and occasionally it will complete and carry on for several hours then fail.
nothing has changed and is not running excessively hot.
Any help, suggestions would be greatly appreciated.?
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Re: QMX+ V2 - I've killed it
Check to see if the metal edge of the left encoder is touching the top of the barrel socket on the main board. Hans suggested covering that with tape to prevent that possibility.
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73, Dan - W2DLC
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Re: QMX (not-plus) power issue
Some helpful numbers to post would be the voltage you built your QMX for, and what is the overall input current draw in receive mode of your QMX??
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For a 12v QMX you should see around 90 mA or so of current when it's on and idle (not transmitting).?
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If it's substantially more than 90mA then your power meter is likely correct, and one of the output power transistors is likely blown/defective.... As a first diagnostic guess.?
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73
de Roy - KI0ER
Littleton, Colorado USA
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Re: Thinking about a project, receiver module + VFO / sig gen
On 19/09/2024 21:01, Eric Hansen, KB1VUN via groups.io wrote: As a bonus, I though it might be fun to see if I could make a VHF (FM broadcast, NOAA, 2m ham) receiver.? That's the reason for asking about the wider tuning range. Eric, I certainly can't help with coding:-) The Softrock/QRP Labs RXs are limited by the hardware which, I think, will not go much above 60-70MHz. So to use them at VHF you would need a mixer or tuner chip in front. An example here 73 Alan G4ZFQ
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Re: qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
I have the New PCB with the power supplies on the main board. I will inspect everything again.
?Steve where didyou make connection for the D103 ??
?I am thinking , mine on top of the PCB? IC101 output to a nearby VDD JP106 hole.
?
I am unclear if that is correct,? ain't done it yet.
Lee,
?AA7HC
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Re: QMX+ V2 - I've killed it
Thanks again all. I can’t connect to my PC at all. No signs of shorts to the case internally but I can’t rule that out as the cause.?
I’ll order replacements for Q3 and Q5 and see how that goes. Wonder if it’s worth ordering some other components that might also need replacement. Hm… which ones?
I had to replace the 5V board on another QMX recently due to a scratchy 12V supply - the bad connection there was on the external PSU, and the simple board swap fixed it. Not quite so easy with the SMPSUs being integrated into the main board with V2. In that case I was able to connect to the terminal and see that the 5V board was dead.?
Steve MW0KST
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Re: QMX+ Filter Cascading Question
Thanks Stan.? Actually those first two sentences are the lightbulb on how to use the filters!? Much appreciated.
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N4TTU - TL
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Re: qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
Stan - good point. A physical connection between +12V and VDD could blow up D103. A couple components that are just a bit too close is all it would take to set up a failure mode when the main board is flexed a bit.
My QMX+ is still waiting to be built. I did fix a QMX+ for my good friend Rich N3III a week ago. The problem with his radio was traced to a missing D103. Looked like it was ripped from the board, along with its pads. Fortunately that was easy to fix, and his QMX+ is working super-well now.
73, Steve, N3SB?
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-------- Original message -------- From: Stan Dye <standye@...> Date: 9/19/24 10:44 PM (GMT-05:00) Subject: Re: [QRPLabs] qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
A momentary short from the 12V bus to VDD could blow up D103.? Is there something mechanically close that could come together and short these two? Maybe pins contacting the chassis? I don't have QMX+, I got QMXmini, so I can't directly check.
Lee;
Wow - that 3.6 Volt Zener should not have seen an overstress condition sitting on the 3.3 Volt VDD bus - unless the switching regulator did something it shouldn't have.
Looking forward to hearing about the result you obtain when the D109 is replaced.
73; Steve, N3SB?
-------- Original message -------- Date: 9/19/24 8:54 PM (GMT-05:00) Subject: Re: [QRPLabs] qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
Steve,
?Thanks for the info.? I checked the ground to vcc and showed 330 ohms.? found D109 Zener Diode exploded.on one end. I did get a voltage reading of 2.1 volts. on it though.
?I removed D109? and the ground is gone.
?Mouser Parts on order.?
?I will update this when I get the part.
?Thanks for the help.
?Lee
AA7HC
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Re: qmx+ SCHEMATIC QUESTION hELP UNDERSTANDING
Get new p/s boards! I tried repairing them and there ended up being additional issues. I don't think it's worth risking damage to the main boards with repaired p/s boards.
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Check your Vdd and Vcc resistances (with p/s's removed) to make sure you didn't damage the main board.?
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73, Dan? NM3A
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Mark Knight
Donald S Brant Jr
Dave, G8PGO
Daniel Conklin
Tom Lewis - N4TTU