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Re: Ultimate 3S reciever question

 

Ian,
Thanks.? I run several qrss receivers here, so I'm familiar with how it's done in basic terms. I was planning on letting the U3S do its TX thing and use the receiver into wsjt-x for wspr decode, either along with/ between transmissions. So i think it will perform as i had hoped.?
?
I would like to have another transmitter that can do wspr and fskcw at lower power than my QCXs. If i can RX in between Tx, then the receiver add on would be a good choice.?
?
--
regards,
Bryan, N0LUF
Re: Dead Radio Repair by W1NC-- A Detailed Expert Case Study

 

I'm in awe, we all owe Jeff W1NC big time.?
Without him to back up our debug efforts, buying a QMX would be much riskier?
Reading how he went about this is instructive.
?
Here's some other debug notes he's given us:
Another repair job: ??/g/QRPLabs/message/134035
Swapping out a chip: ?/g/QRPLabs/message/128025
Almost certainly a bunch more that I have missed.
?
Jerry, KE7ER
?
?
?
On Thu, Jan 9, 2025 at 08:36 AM, Bill Jobes wrote:

To follow up on a post praising Jeff Moore's (W1NC) revival of my dead QMX+, I wanted to share, with his permission, part of Jeff's email to me detailing the steps he took to convert my electronic brick into a functioning rig.
?
- Bill? W3WJ
?
"Here is what I found and did:
?
1) Disassembled all boards, scraped off old flux, cleaned with 99% IPA
The reason I do this on every rig is that it forces me to look closely under the microscope at every solder joint and component. ?
Often solder splashes or cold joints can be hidden by the dried up old flux.
2) Inspected under 10x - 20X microscope
Fixed a few cold solder joints
Tested for shorts between VDD to GND and VCC to GND.? VDD had a 2 ohm short to GND - isolated to CPU
Replaced CPU and powered up again - blew the second CPU at > 8V DC power input
Removed CPU, cleaned pads and soldered in new CPU (100 pins) once again
Also replaced EEPROM chip - these often blow when the CPU blows up
Short is now gone
Spent many hours trying to isolate the integrated SMPS supplies from the CPU so it wouldn’t blow up again and diagnose the problem with the SMPS circuit.
Finally gave up that approach since the firmware and hardware are tightly integrated (an understatement) as it was impossible to diagnose.
I ended up replacing the entire SMPS set of circuits except for one inductor.
SMPS problem resolved now!
3) Powered up at 6.1V and installed rev 27 of firmware
Factory reset - all good
The reason I use 6.1 volts is because it’s the lowest voltage that will allow the rig to operate (except for TX) and will minimize damage if something is terribly amiss.
4) Tested on bench at 6.1 V AF, image scan, A/D scan and rf scan functions - all found to be good except 80 & 60 meters
Found one toroid was soldered into the incorrect hole - fixed that.
Now all bands test correctly for RX
5) Shut down the rig and increased voltage to 12v.? Tested LPF & TX functions on all bands at 12V.?
Power out 3.5 - 5.5 watts depending on band except 6 meters (1 watt)
discovered one LPF toroid for 6 meters had 16 turns instead of 15.? Corrected and reinstalled toroid
Now all bands have great RF output
LPF shapes and cutoff frequencies all good
TX bias current is correct for every band (30ma)
TX power reduction (to about 1-2 watts) works well for LPF scans - This is an important test
SWR bridge works well for all bands
6) Measured minimum discernible signal on all bands - < .02 microvolts - very good
7) Measured frequency accuracy - within 2 HZ
8) Measure spectral purity on all bands - easily exceeds FCC requirements and meets QMX design goals
9) Reassembled into case and retested everything one last time - now 100% RX, TX all modes, all bands
?
Total time spent - I have lost count but > 16 hours. "
?
?
?
QMX POTA Support...

 

?
Firstly...apologies to all for such a newbie question, but I only just ordered a QMX and am just now learning CW :)
?
I was hoping to put together a rig for POTA while doing AT section hikes and was looking for recommendations for:
?
- battery
- antenna
- tuner
- plus anything else that I haven't even thought of yet :)
?
Thanks!
?
Len S
KC3PWB?
--
Len S
KC3PWB
Re: These cursed little pwr supply boards...QMX

 

Thanks Karl--and others-- who replied...I will check the wiki.?
?
I have played around with a lot of the qrp labs stuff...its great quality and never an issue. Just a bad run of luck lately is all. There is a lot going on in that little board.?
?
S
Re: New silicone enclosure feet

 

开云体育

Good Point.? I forgot about that.? Can’t just put it in an envelope.?

?

John

?

From: [email protected] <[email protected]> On Behalf Of Michael N6MST via groups.io
Sent: Thursday, January 9, 2025 11:28 AM
To: [email protected]
Subject: Re: [QRPLabs] New silicone enclosure feet

?

On Thu, Jan 9, 2025 at 08:18 AM, John Saari wrote:

Thanks, but $16 shipping for a package of pads and QCS + power button cover??

?

John

I mean, Turkey to Georgia (state, not country) is pretty far. I don't think they do Forever Stamps over there...
Re: Ultimate 3S reciever question

 

Hi Bryan,
The U3S is a stand alone transmitter only in that it does not need a computer to generate the wspr signals.? However to receive and decode wspr signals you will need a separate receiver, the audio of which is sent to a computer running decoding software such as WSJTX.? This software can then send information to wsprnet.
I have been using an U3S as a wspr transmitter for many years and have more recently added the QRP Labs receiver and polyphase modules.? The receiver audio is fed into a Raspberry Pi 4 computer running WSJTX and it all works very well!
?
Regards
Ian G3VAJ
Re: question 50 watts amp

 

Hello, Hans,
I am using the 50W QCX PA with my QMX+ quite successfully. It works fine.
There are some things that I am strictly sticking with when using this combination.
1. I am using a +5V PTT so I lowered the R210 in the QMX+ by adding a 100R (at least) in parallel. This makes the PTT RX/TX switching reliable.
2. Use a quality USB cable with ferrite cores.
3. Lower the QMX+ output power by lowering the QMX+ supply voltage. I am using about +9V for my +12V QMX+!
4. Always have the RF input and output cables apart!
5. Use a good PS for the PA. I am using +22V/5A.
--
GL and 73 Bojan S53DZ
Re: Best QMX AGC settings?

 

Hi Hans,

No, I did not try the other settings.

I have read over the descriptions of what they do, and
not knowing the architecture, I can't relate the settings
to the problem I am seeing.

I'm an engineer, whacking at problems randomly is rarely
productive.

When the AGC is exposed to nothing but strong signals,
like W1AW, it is by far the best I have ever used.

When the AGC is exposed to high ambient noise outside of
the CW filter's bandwidth, the audio produces sounds that
simply cannot come out of a properly functioning CW filter.

Sibilance and cracky sounds have high frequency components
out to the 9th harmonic and beyond. They shouldn't be
coming out of a CW filter.

They audio levels seem too low to have driven any of the
audio hardware into clipping. Much higher levels haven't.

I too am enthusiastic about this product, so I understand
the excitement it brings.

But, being reminded that I checked a box when I made my
purchase acknowledging this is a Beta release, as if that
makes my questions unreasonable, feels like something else.

I don't want to see your effort "knee-capped" by fixable
problems you don't know about.

-Chuck Harris, WA3UQV


On Thu, 9 Jan 2025 12:38:11 +0300 "Hans Summers via groups.io"
<hans.summers@...> wrote:
Hello Chuck


Initially I tried both lower and higher AGC thresholds, and
found they did not help the situation. OFF seemed to do the
best at eliminating the noise modulation of the CW tones.
Did you try changing the other parameters other than AGC threshold?

I will look into it again when I have a chance; it has been a while
since the AGC functionality was added and I get the impression
generally most people think it is working well.

I think that there are settings which could cause it to be scratchy.

I do intend to create some "known good" settings to choose from to
make it easy; leave the extensive full configurability in there for
people who want it, but a few easy settings.


My SWAG on the problem is that the AGC routine's inputs
are from before the CW filters, and the AGC routines outputs
affect the audio levels after the CW filters.

Something is causing the AGC to modulate the CW notes with
noise that otherwise isn't within the CW filters bandwidth.

How do I know this? The noise is too sibilant and crackly
to have passed through a narrow CW filter.
The AGC action takes place AFTER the CW filter. If the crackling was
generated by AGC that was ahead of the CW filter then the crackling
would be filtered out by the CW filter...


I could not help but notice that many on this group speak
possessively about this product, as if they had something to
do with its creation.

I could not help but notice that many on this group beat their
chests threateningly and point out reasons why I should shut
my mouth.

Perhaps it is simply pride because you acted on one or more of
their suggestions?
Just enthusiasm, I suspect; most people here have had a lot of fun
with the QRP Labs products. I am reading most of the posts here, I
had not noticed people beating chests threateningly in regard to your
questions.


I meant no disrespect. My feeling was that if others are
speaking on your behalf, I should like to know so I can treat
their opinions as being more informed.

No problem :-) Nobody speaks on my behalf.

73 Hans G0UPL
Dead Radio Repair by W1NC-- A Detailed Expert Case Study

 

To follow up on a post praising Jeff Moore's (W1NC) revival of my dead QMX+, I wanted to share, with his permission, part of Jeff's email to me detailing the steps he took to convert my electronic brick into a functioning rig.
?
- Bill? W3WJ
?
"Here is what I found and did:
?
1) Disassembled all boards, scraped off old flux, cleaned with 99% IPA
The reason I do this on every rig is that it forces me to look closely under the microscope at every solder joint and component. ?
Often solder splashes or cold joints can be hidden by the dried up old flux.
2) Inspected under 10x - 20X microscope
Fixed a few cold solder joints
Tested for shorts between VDD to GND and VCC to GND.? VDD had a 2 ohm short to GND - isolated to CPU
Replaced CPU and powered up again - blew the second CPU at > 8V DC power input
Removed CPU, cleaned pads and soldered in new CPU (100 pins) once again
Also replaced EEPROM chip - these often blow when the CPU blows up
Short is now gone
Spent many hours trying to isolate the integrated SMPS supplies from the CPU so it wouldn’t blow up again and diagnose the problem with the SMPS circuit.
Finally gave up that approach since the firmware and hardware are tightly integrated (an understatement) as it was impossible to diagnose.
I ended up replacing the entire SMPS set of circuits except for one inductor.
SMPS problem resolved now!
3) Powered up at 6.1V and installed rev 27 of firmware
Factory reset - all good
The reason I use 6.1 volts is because it’s the lowest voltage that will allow the rig to operate (except for TX) and will minimize damage if something is terribly amiss.
4) Tested on bench at 6.1 V AF, image scan, A/D scan and rf scan functions - all found to be good except 80 & 60 meters
Found one toroid was soldered into the incorrect hole - fixed that.
Now all bands test correctly for RX
5) Shut down the rig and increased voltage to 12v.? Tested LPF & TX functions on all bands at 12V.?
Power out 3.5 - 5.5 watts depending on band except 6 meters (1 watt)
discovered one LPF toroid for 6 meters had 16 turns instead of 15.? Corrected and reinstalled toroid
Now all bands have great RF output
LPF shapes and cutoff frequencies all good
TX bias current is correct for every band (30ma)
TX power reduction (to about 1-2 watts) works well for LPF scans - This is an important test
SWR bridge works well for all bands
6) Measured minimum discernible signal on all bands - < .02 microvolts - very good
7) Measured frequency accuracy - within 2 HZ
8) Measure spectral purity on all bands - easily exceeds FCC requirements and meets QMX design goals
9) Reassembled into case and retested everything one last time - now 100% RX, TX all modes, all bands
?
Total time spent - I have lost count but > 16 hours. "
?
?
?
?
Re: New silicone enclosure feet

 

On Thu, Jan 9, 2025 at 08:18 AM, John Saari wrote:

Thanks, but $16 shipping for a package of pads and QCS + power button cover??

?

John

I mean, Turkey to Georgia (state, not country) is pretty far. I don't think they do Forever Stamps over there...
Re: Best QMX AGC settings?

 

? QMX Manual G4EDG Ron Other K7VIQ KL7MJ W5NR WA3UQV W2DLC
Threshold 8 4 7 7 8 4 7 12 8
Slope 80 50 95 60 80 80 60 80 65
Noise 10 0 5 5 10 10 5 10 9
Hang 80 2 50 30 80 30 30 80 55
Smooth 50 0 99 50 50 50 50 50 60
Recovery 10 60 40 50 10 10 50 10 8
Sample 5 2 4 4 2 2 2 2 2
S9 S9 S9 S9 S9 S0 S6 S9 S9 S9
AGC display ON ON ON ON ON ON ON ON ON
AGC dB per bar 3 3 3 3 3 3 3 3 3
--
73 - Petr, OK1RP

QMX Midband #5278 | fw: 1_00_019
Re: New silicone enclosure feet

 

开云体育

Thanks, but $16 shipping for a package of pads and QCS + power button cover??

?

John

?

From: [email protected] <[email protected]> On Behalf Of Hans Summers via groups.io
Sent: Thursday, January 9, 2025 8:47 AM
To: [email protected] Notification <[email protected]>
Subject: [QRPLabs] New silicone enclosure feet

?

Hi all

?

This afternoon we took delivery of 50,000 silicone sticky enclosure feet (a.k.a. furniture bumper pads). These silicone pads are transparent once applied. They have a 10mm diameter, domed cross-section and 1.6mm height. They replace the cylindrical black rubber pad feet formerly supplied with QRP Labs enclosures.

?

An issue with the black rubber feet supplied with QRP Labs enclosures until now has been that after a while they get knocked off and lost, or they travel across the base of the enclosure; I am sure many of you have noticed this. In our testing these silicone feet appear a good improvement, and I think the lower height and the domed shape will make them much less likely to be disturbed or knocked off.?

?

It's a much larger stock of sticky feet than we've ever had on hand before. And, I bought them direct wholesale from the manufacturer themselves, right here in Turkey; so I can easily buy another box whenever I like. Therefore I also added them to the QRP Labs shop in case they are useful to anyone:

?

10pcs $1.20:

8pcs $0.30:?

?

Therefore currently everything is in good stock EXCEPT:

  1. Si5351A Synth modules (which means also U3S, and VFO kits which contain this module)
  2. 50-ohm dummy load (PCBs - all the other parts resistors, capacitor, diode, BNC connector already arrived)

Both the Si5351A Synth modules and the dummy load PCBs are already on the way with FedEx since Tuesday, currently in transit at Cologne, Germany. I expect to have them in hand sometime mid next week.?

?

So we're now shipping all pending orders except those containing Dummy load and Synth kits, which should start shipping mid next week.?

?

73 Hans G0UPL
Re: question 50 watts amp

 

hanz YL3JD via groups.io <yl3jd@...> wrote:

Does some one already did this and are there any special things to think
of ?
I did with QDX. It worked fine, until one day the amp started oscillating
(and didn't stop when PTT was released). One of the resistors in the input
attenuator started smoking, four chips in the QDX (two 3253 and two input
amplifiers) died. Probably the amplifier fed high voltage to the QDX
antenna connector. I replaced the chips and ceased further experiments.

Later I recreated the amplifier (I used the original schematics of the amp
itself, but made my own controller, with relays instead of PIN diodes, and
a nice regulated "holdoff"), but it still oscillates now and then. It's
even worse than it was with the original design (I was testing it without
radio connected, so no damage this time).

I don't remember the exact oscillation pattern, I remember there were two
frequencies there (one was 6 MHz, another way higher, 50 MHz if memory
serves me well). I can connect it and check if you like (but it's my
design based on Hans's schematic, so it might differ).

I was thinking about adding an LPF at the input, but frankly speaking I
have no idea how to do it with the current design (the gate path is
low-impedance and I'd like to keep it this way). Plus I have no idea how
these oscillations even get from the output to the input. Capacitance of
the relay? Wouldn't make sense, there's an LPF there. So maybe it's the
power line? I switch power to transistors with a MOSFET (I don't keep them
powered during RX), smoothing capacitors are before this MOSFET (because I
want to cut the power as soon as PTT is released). I have some small
capacitors after the power-switching MOSFET, maybe I should increase the
capacitance a little and see what happens.

I wanted to investigate it further, but other things got in the way and
the project is abandoned for now. I might revisit it in the future (at the
same time I'm thinking of abandoning the PA project, buying Yaesu FT-891
as my main rig, selling QDX, and keeping QMX strictly for portable QRP
work).
Ultimate 3S reciever question

 

I am considering a U3S purchase when the processor chips come in.?
?
Can the U3S receiver be made to upload to wspr.net? Im trying to determine the utility of the receiver add on.
--
regards,
Bryan, N0LUF
Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)

 

Hans Summers via groups.io <hans.summers@...> wrote:

Several things I don't understand. I asked about if you could connect just
because I wanted to know if the USB connection was working; If it is, that
kind of means that the 25MHz signal must be present.
It's working and stable. But the 25 MHz signal is present. That's why the
waveform lines are "thick" -- it's because of the 25 MHz signal, it
appears when I zoom in.

The problem is that the 25 MHz signal is modulated by this weird, ~833 Hz
one. So it's severely distorted. The scope's time base on these photos was
set to show this low-frequency modulation.

Here's a video of TCXO output (before the gate) when I switch the time
base:



Maybe it's enough for the PLL in the CPU to lock, but *almost* enough for
the PLL in the sync chip (so most of the time it's locked, but falls out
of lock here and there, and that's why CLK outputs are momentarily
disabled)?

It looks like the vertical division on your 'scope is 100mV/div in which
case the waveform also isn't the 3.3Vpp expected at the logic gate
output... so are you sure of your measurement? It's confusing to me...
It's correct. I set the switch on the probe to 1:10 (to have greater
impedance of the probe), but forgot to switch it in the scope's menu, so
the scope still thinks it's 1:1.

So it shows 100 mV / div, but in reality it's 1 V / div.

In the video above it's set correctly and shows 1 Vpp (but it's TCXO
output, not gate output -- gate output is around 3.3 Vpp).
question 50 watts amp

 

dr ops,
?
Thinking of using the 50 watts amp for the qcx but now for qmx plus.
Also will use an external LP filter for different bands.
?
Does some one already did this and are there any special things to think of ?
?
73 hanz YL3JD
Re: Old Progrock 27MHz crystal replacement with 25MHz one

 

TNX Alan,
I'm using the "manual" programming method but with a contaves binary-switch instead of the dip-switch. My firmware is 1.01
73
Alex ik0vaq
Re: QMX+ 160m problems

 

Excellent advice Dan !
I took 1 turn off L520 and redistributed the turns evenly and measured 2.5W at 9V supply.
I can also now hear our local 6m beacon, so I will leave it at that.
Many thanks.
73 Hugh GM8FXD
Re: I had one lockup after a band change

 

I also tried to tune my rig with a 50' Coax cable that I forgot to plug into the antenna, so that is most likely what happened. I actually captured that moment on the video I posted earlier in the beginning of the video.
Re: Best QMX AGC settings?

 

I applied these settings to my QMX last night and listened on all 6 bands on my Mid-Band and it's a vast improvement for me. Thanks!
?
---
Anyway, I'm happy with my settings which most of the time are:
?
Threshold S: 8
Slope dB per dB: 65
Noise Filter: 9
Hang time: 55
Smooth samples: 60
Recovery dB/s: 8
Sample Blocks: 2
S9 sounds like: S9
AGC Display: On
AGC dB per Bar: 3
?
But, I'm also still experimenting.
--
73, Dan - W2DLC
6361 - 6380 of 141142