Re: QMX HIGH BAND NO RF OUT AFTER ANOTHER 10 hour WSPR TRANSMISSION
Giuseppe, that is encouraging. JZ
On Thu, Feb 22, 2024 at 4:22?PM GIUSEPPE < iw8rsb@...> wrote: Hi John, this evening I tested the QMS in cw transmission and I listened to it on another radio, the signal is very strong, and the cw dit and dat tone is excellent, I was not able to test the absorption to calculate the power outgoing and I didn't even have an antenna tuner because I was in the car doing some SSB QSOs.? If I can, I'll continue trying them from home later.? 73 bye
Giuseppe iu8eun
Hello Giuseppe,
I'm looking forward to your additional information! How well the QMX is receiving, and whether you can hear your own transmission on another radio will provide useful clues.
Usually when massive BS170 failure occurs in QDX the current draw in RX becomes highly elevated as well. In QMX, the envelope modulator hides some of that by reducing the resting voltage to the PA stage. You can change that voltage via ?"advanced settings", but the results might be concerning!
Another characteristic of large scale BS170 failure is that you can usually smell the smoke!
The few BS170 failures I have seen reported on QMX involved other unfortunate events: failure of a clock generator, for example, or a catastrophic short circuit from a bit of wire or a solder blob.
Please do look at T501. If a solder joint has opened up on the secondary, the PA will have no load on it and no power will be delivered to the antenna. Current draw will be below normal.
JZ
On Thu, Feb 22, 2024, 7:19?AM GIUSEPPE < iw8rsb@...> wrote: Hi John, I purchased the QMX already assembled, I also made the recommended modifications and everything was fine, I made several QSOs in the various bands nearby, the RF power was 6W on the major bands, the antennas I use are all monoband with swr lower than 1, then I decided to test it in WSPR transmission on 10 meters with 5 w output and swr 1, it transmitted for about 10 hours and the following morning I no longer had any reception report.? in reception absorbed 90 mA and transmission now 190 /180 mA.? John I haven't tried listening to see if anything comes out of the radio yet, I'll do it today, I don't have many tools available to do the tests.? I was thinking about transistors.? Thanks so much for your help, I'll let you know.? 73
Giuseppe iu8eun
G., one more thing: Check the solder joints on T501, especially on the output (secondary) side.? JZ
Giuseppe, IMO the problem is elsewhere. BS170 failures on QMX appear to be quite rare.
Did you assemble that QMX or purchase factory-built? What is the current draw you see in RX mode? Is RX working properly on all bands? When you attempt to transmit, can you hear your signal on a nearby receiver?? If we need to dig in more deeply, what test equipment do you have available and are familiar with?
JZ KJ4A
On Thu, Feb 22, 2024 at 5:21?AM GIUSEPPE < iw8rsb@...> wrote: hello everyone, NO POWER COMES OUT OF MY HIGH BAND QMX AFTER A 10 hour WSPR TRANSMISSION on 10 m, in cw transmission it absorbs 290 mA on all bands, could it be the bs 170 transistors that have gone up in smoke??
Giuseppe iu8eun
|
Re: QMX HIGH BAND NO RF OUT AFTER ANOTHER 10 hour WSPR TRANSMISSION
Hi John, this evening I tested the QMS in cw transmission and I listened to it on another radio, the signal is very strong, and the cw dit and dat tone is excellent, I was not able to test the absorption to calculate the power outgoing and I didn't even have an antenna tuner because I was in the car doing some SSB QSOs.? If I can, I'll continue trying them from home later.? 73 bye
Giuseppe iu8eun
Hello Giuseppe,
I'm looking forward to your additional information! How well the QMX is receiving, and whether you can hear your own transmission on another radio will provide useful clues.
Usually when massive BS170 failure occurs in QDX the current draw in RX becomes highly elevated as well. In QMX, the envelope modulator hides some of that by reducing the resting voltage to the PA stage. You can change that voltage via ?"advanced settings", but the results might be concerning!
Another characteristic of large scale BS170 failure is that you can usually smell the smoke!
The few BS170 failures I have seen reported on QMX involved other unfortunate events: failure of a clock generator, for example, or a catastrophic short circuit from a bit of wire or a solder blob.
Please do look at T501. If a solder joint has opened up on the secondary, the PA will have no load on it and no power will be delivered to the antenna. Current draw will be below normal.
JZ
On Thu, Feb 22, 2024, 7:19?AM GIUSEPPE < iw8rsb@...> wrote: Hi John, I purchased the QMX already assembled, I also made the recommended modifications and everything was fine, I made several QSOs in the various bands nearby, the RF power was 6W on the major bands, the antennas I use are all monoband with swr lower than 1, then I decided to test it in WSPR transmission on 10 meters with 5 w output and swr 1, it transmitted for about 10 hours and the following morning I no longer had any reception report.? in reception absorbed 90 mA and transmission now 190 /180 mA.? John I haven't tried listening to see if anything comes out of the radio yet, I'll do it today, I don't have many tools available to do the tests.? I was thinking about transistors.? Thanks so much for your help, I'll let you know.? 73
Giuseppe iu8eun
G., one more thing: Check the solder joints on T501, especially on the output (secondary) side.? JZ
Giuseppe, IMO the problem is elsewhere. BS170 failures on QMX appear to be quite rare.
Did you assemble that QMX or purchase factory-built? What is the current draw you see in RX mode? Is RX working properly on all bands? When you attempt to transmit, can you hear your signal on a nearby receiver?? If we need to dig in more deeply, what test equipment do you have available and are familiar with?
JZ KJ4A
On Thu, Feb 22, 2024 at 5:21?AM GIUSEPPE < iw8rsb@...> wrote: hello everyone, NO POWER COMES OUT OF MY HIGH BAND QMX AFTER A 10 hour WSPR TRANSMISSION on 10 m, in cw transmission it absorbs 290 mA on all bands, could it be the bs 170 transistors that have gone up in smoke??
Giuseppe iu8eun
|
Hi Dave, all
We DID find an issue but it's a small one and should be easy to resolve.?
Who knew - but apparently the BSS84 P-channel MOSFET from different manufacturers are significantly different... In particular, some have built-in ESD (Electrostatic discharge) protection with a TVS diode across the gate-source, and others don't. Q202 on page 2 of the schematic has its gate connected directly to the left rotary encoder button. At the time you're soldering on the 2x4 pin header for the controls board, nothing at all is connected to the gate. I didn't have any problems with my soldering station but some of my colleagues, with their lesser soldering irons, did show a tendency to kill Q202.?
On several assembled QMX here there was a clear tendency for the Q202 transistor to be killed by ESD during assembly. The symptoms then are that the QMX is on whenever power is plugged in, it doesn't wait for you to press the ON button; nor can you subsequently turn it OFF with the button while power is still applied. It can also be confirmed by a resistance reading of under 100K between Gate and Source (it should be extremely high resistance).
It's still not completely clear how it happened but the current best theory is that the Rev 3 boards were made with a different manufacturer's BSS84 to the Rev 1 and Rev 2 boards. It's also possible to test the voltage drop across the internal body diode, Rev 1 and Rev 2 always measure 0.58V on my meter but Rev 3, between 0.61 and 0.63V, indicates clearly that there is some difference.?
I had a few P-channel MOSFETs on hand having internal ESD protection circuits, but only 18. After replacement the?ESD sensitivity was removed,?in testing none were destroyed. We sent out those 18 QMX Rev 3.?
While the instructions quite clearly do state in bold red font (assembly manual page 5) that ESD precautions?should be observed, we all know that many constructors aren't going to observe ESD precautions or will do so inadequately. So though I could hide behind my bold red disclaimer, I don't really want to simply ship out the Rev 3 boards like that and cause an increased rate of construction failure.?
Therefore I suspended shipments; I located some BSS84AK made by Nexperia (formerly NXP, and before that,?Philips), in stock at a Turkish distributor, and ordered 350 on Tuesday. According to the Nexperia BSS84 datasheet they have integrated ESD protection diodes rated for 1,000V ESD.? See? . With any luck they should be here tomorrow. So the plan is to replace Q202 on all 1,000 QMX Rev 3 boards with this Nexperia BSS84AK, assuming it passes initial testing. I'll order the other 650 later.?
73 Hans G0UPL
On Thu, Feb 22, 2024, 8:11?PM Dave Schmidt < dgschmidt@...> wrote: Hello Hans,
How is the V3 testing and shipments going?? I see I have a tracking number but no acceptance of the item yet - hopefully this doesn't mean you found an issue.
Dave
AI6VX
|
Matt,
Yes, there is clearly a difference that begs? some explanation. It is not at all obvious to me what is going on.
The broad flat curves of your two experiments are more like what I would expect to see from a series L-C combo which is attempting to BPF protect a high Z load. The high Z load kills the Q of the L-C combo. The QDX self-sweep is, to me at least, the harder to explain, especially without a complete and thorough understanding of exactly how it is produced.
In QDX the way in which the swept signal is introduced (from CLK2 via a 100K resistor) may be a complicating factor. Dunno. Considering that even a 1pF self-capacitance will have less reactance by half than that resistor even at 3.5MHz, and it will fall further with increasing frequency, it may have an outsized influence.
JZ
John and everyone else
Thank you for your insights -- they make a lot of sense. I gave this quite a bit of thought and decided that it would be best to make an end-to-end measurement first before digging into this any further. So I added T2 back into the circuit. This way, the QDX is unmodified apart from a missing T1. I injected a -50 dBm signal into the antenna port at frequencies between 12 and 18 MHz in 200 kHz increments. That covers the same range as my 20 m test. I configured these frequencies into WSJT and used the vertical decibel indicator in WSJT to quantify the amount of RX signal. I recorded the frequency / dB pairs during a sweep. the following plot shows the terminal sweep at the left, the somewhat flawed manual VNA measurement reported before in the center (unaltered, the issues that we discussed are still there), and the new end-to-end measurement at the right.
In my opinion, the terminal sweep is still odd given the other two measurements...
Regards
Matt
|
QCX older model output clipping?
OK Output is about 3 watts,? Actually its almost 4 watts,? The jumper has a ton of loss...... but I get the same wave form with a dummy load.? The tops of the wave are flattened,? I am assuming this is due to clipping?? This is a 40M QCX Recently built by me.?? Any ideas and suggested fixes?? Also the tone sounds just a tiny tiny bit raspy when I hear it on my main rig.? attached are some Pics.
Thanks ahead of time
W5LNA
|
Re: QMX on Inovato Quadra
Yessir, that's all the way up top, first thing checked!
|
John and everyone else
Thank you for your insights -- they make a lot of sense. I gave this quite a bit of thought and decided that it would be best to make an end-to-end measurement first before digging into this any further. So I added T2 back into the circuit. This way, the QDX is unmodified apart from a missing T1. I injected a -50 dBm signal into the antenna port at frequencies between 12 and 18 MHz in 200 kHz increments. That covers the same range as my 20 m test. I configured these frequencies into WSJT and used the vertical decibel indicator in WSJT to quantify the amount of RX signal. I recorded the frequency / dB pairs during a sweep. the following plot shows the terminal sweep at the left, the somewhat flawed manual VNA measurement reported before in the center (unaltered, the issues that we discussed are still there), and the new end-to-end measurement at the right.
In my opinion, the terminal sweep is still odd given the other two measurements...
Regards
Matt
|
Yeah... "Locked in transmit" seems unlikely for a simple "failure
to connect", though.
There's a common thing that's reported on the 991 where it goes
into transmit, if on, when the computer is rebooted. That's
because when DTR (or is it RTS) goes low, it acts as the default
PTT. Maybe that's happening here?
I vaguely recall reading that order is important-- Disconnect
power and USB from the QDX, turn computer on, apply QDX power,
plug in USB, something like that. Something about the USB init
negotiation with the computer only happens once, with the QDX (and
QMX too!)
I keep coming back to seeing USB, not COM and Audio. The computer
is seeing something plugged in (USB), but not the correct devices.
I don't remember, was there a driver that's supposed to be loaded?
Is there something showing in DM Unknown Devices?
In DM, go into View and show hidden devices (i.e., devices that
are not present.) I'd delete the hidden devices, especially if
there are a lot, just to simplify things.
You could try re-flashing the QDX memory. (How-to is in the
manual!) If you can't get to the flash drive to load the firmware,
suspects are your USB cable, and some problem on the host
computer.
Have you tried known good USB cables? How about another host
computer? Are you using a USB hub? What if you connect directly to
the computer?
Good Luck, William!
73, Paul -- AI7JR
On 2/21/24 21:20, k6whp wrote:
Paul,?
Yes it is. My issue is the apparent non-recognition of the QDX by
the laptop. Apparently, one just plugs every thing in, fires up
WSJTX, and the radio takes off in receive mode.?
While the two "USB ports" are visible in the device manager, there
are no connections made and the QDX is locked in transmit.?
As I said, I just need to determine if the radio is functioning or
is it a connecy/set-up issue.?
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got
worse."
--
Paul -- AI7JR
|
Re: QMX on Inovato Quadra
WSJT-X also has a vertical slider for TX power over on the right hand side/bottom. Is that turned all the way up? (I hope that’s where the slider is… I’m picturing it in my mind.)
—Tim NC0Q?
|
Re: QMX on Inovato Quadra
Addendum: everything *that I can see from the desktop* is turned up. Nothing will be taken personally if someone asks if I checked "x" "y" or "z" boxes, because I will be there first to say that I probably didn't, or thought I did and forgot about it. Thanks!
|
Good afternoon everybody, from Louisiana. I have the QMX rev. 1 low band, which has functioned flawlessly since its completion, and *still functions correctly* hooked up to a PC running WSJTX.
I have recently gotten a HamClock bundle (Inovato Quadra flashed with Debian {which I've never used before}) and I can decode just fine, run Putty okay, etc... except for transmitting. When I attempt to transmit FT4 or FT8, the program shows a brief flash of one dot under VFO A indicator, and brief output on the power meter before killing the transmission and switching back to AGC meter (less than a second).
I know the FW_17 manual says that this is likely a muted sound problem on the computer itself, but I have everything turned up to maximum, input registered to QMX input and output on QMX output. Sound is all the way up.
Ideas, anyone? I should note that this is my FIRST debian based project and I am NOT a programmer.
Thank you in advance, AD5MO.
|
@CoolDuke - The one I've made several of is
and I've also made the same guy's larger base mounted version, it's on a piece of 1/4" stainless steel which turned out to not be large and heavy enough to stay down so it's still a 2 handed operation unless I tape it to the desk.
Check out the existing remixes on them, the base mounted at least has an improvement for the paddle to hold a nut which will prevent it from coming loose as easy.? The mini really needs this too and if I ever get around to it will remix it myself and add that and a couple other improvements I feel it needs.? 2 of the minis have a pen spring, which is ok.? The other (and the base mounted) I glued on opposing neodymium magnets which makes the action feel a lot better imo.? I also like the retractable cable which is a nice portable kit addition.
(sad qmx in the background, will be having surgery performed in a few days)
|
Hello Hans,
How is the V3 testing and shipments going?? I see I have a tracking number but no acceptance of the item yet - hopefully this doesn't mean you found an issue.
Dave
AI6VX
|
Re: QDX V3 SWR Sensitivity ?
I use a MFJ 1979 with choke Balun and radials. Tune it with NANO VNA. Works great.
On Thu, Feb 22, 2024 at 10:22?AM Mike KK7ER < groupio@...> wrote: I hate to say it, but the QMX (with SWR protection) would have been a better choice.
Those loaded telescoping whip antennas have narrow resonance and can be finicky to tune.
For me, just touching the coax connector with my hand changes the resonant point and SWR.
I would not trust one with my QDX.
I always use an EFHW with it after verifying SWR.
My 2 cents.
73, Mike KK7ER
|
For my portable QDX setup I'm working on (going to try and build a 40/30/20/15 version)... I ordered an EFHW kit from QRP Guys, which has a built in match/single knob tuner and an LED SWR indicator.?
Thinking I'll set up a linked wire setup with it.?
-Nate?
N8BTR
|
Re: QMX: Requiescat in Pacem
The correct sentence is "Requescat (third person, indicative) in preposition requiring ablative case answering the question where) pace ablative case object of preparation.? This is the end of your unwanted Latin grammar lesson.
On February 21, 2024, at 23:27, Steve Roberts <robers97@...> wrote:
Thank you for this post.? I am working through an early build failure and this help me isolate it to the 3v3 circuit.? Well really it just gave a great guide on how to work through PON issues.
|
Re: QMX Trouble shooting, difficulty getting firmware installed
Hi. Some quite bad looking solder blobs and at least one dry joint Thai I can see. I suggest you go over the whole thing again, removing excess solder and checking for dry joints.
73
--
David Thomas M0OOR
|
If you have a 3D printer you can do a lot of this cheaply.
I would recommend a trap 20/30/40 EFHW antenna.? Links are fine if you don't mind dropping the antenna to change bands, but the trap antenna is easy enough to build and works very well.? There are plenty of designs available on the internet, so you don't need to buy an expensive kit (K6ARK's kit isn't very expensive, but there are companies out there who will charge you $100 for something you can put together yourself for $30).? I've tried several cases for the transformer and it really is user preference here.
You can make your own battery pack with a 3D printed case.? The first one you build will be more expensive than a Talentcell because you'll also need a charger, but they are cheaper if you make several.? I've made a few for my (tr)USDx's, and I plan to make one for my QMX.
Again, there are several 3D printable keys available.? I use a single lever paddle designed by K6ARK.? It isn't connected to the rig, but it works well and is cheap - particularly if you make several.
73,
Mike, KL7MJ
|
Re: QDX V3 SWR Sensitivity ?
My personal opinion after reading MUCH about the QDX here, and my own experience.....you want some protection from high SWR and/or end of TX spikes especially with the BS170s. Diodes across the finals or L14.?
-Nate?
N8BTR
|
Re: QDX V3 SWR Sensitivity ?
I hate to say it, but the QMX (with SWR protection) would have been a better choice.
Those loaded telescoping whip antennas have narrow resonance and can be finicky to tune.
For me, just touching the coax connector with my hand changes the resonant point and SWR.
I would not trust one with my QDX.
I always use an EFHW with it after verifying SWR.
My 2 cents.
73, Mike KK7ER
|
Paul - AI7JR
Leland Lannoye, W9HIF