Re: QMX on a stick - a minimalistic SOTA activation
#qmx
@DL2ARL
Thanks for pointing this out. Seems I have been lucky so far...and if I think about it, its probably by chance. Routinely, I connect my trigger board first to the powerbank and then I connect the transceiver. By this time, voltage negotiation seems done and the QMX does not see the 5 V to 12 V step anymore. Unfortuantely, I can't edit my initial thread to highlight that this sequence may be important to not kill anything.
So for everyone who is still reading: If you plan to use USB-PD to power your QMX, first connect the trigger board to the powerbank, wait some seconds until voltage negotiation is done, then connect the QMX.
@N6HAN
Correct, it's a BNC connector for RG58. It's drilled open (a little) to match it with the 6 mm brass tube + heat shrink (to isolate the whip from ground). That's basically the base of the antenna. In the meantime, I played around with the coil "design". Because it worked so well on 30m, I wanted to have the option to switch coils and operate on 20m, 30m as well as 40m. Below a picture with some comments.
I did another short SOTA activation with the QMX this morning on 20m, and again it worked amazingly well. 12 QSOs in 15 minutes. And with the new firmware 017 I did not experience any glitches at all. Smooth CW operation. Thumbs up, Hans! For sure many more QMX SOTA activations will follow.
Best,
Matt
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Hello AD5MO!
Tangential to topic, but, I am working on three similar go-boxes and I am very interested to incorporate two Inovato Quadra systems.? My plan includes water resistant power outlets on two of these.? I ordered two Quadra and two 10.1" monitors that were?each engineered to support Raspberry Pi.? The third case has a 12V PC and monitor.? There are three transceivers here to box up.? I am thinking to put Yaesu FT 891 and a QDX together. I want a 2M/70cM go-box for who knows what's coming. So, maybe I will likely use the third case for solar, a battery, and for antennae and connectors.? Your set-up is a different but welcome inspiration.
I appreciate your photo!? A member of a local ham club made one that included an MFJ UTC/Local clock, a white board, band plan, LiPoFe4 battery, I liked his that was easy to set up and take down in less than 5 minutes.? I want to include my QDX, an azmithal map and carry the battery separately.? Other members of this same local club use a go-box to contain systems that they set up on site rather than have mostly packed with connections already made like yours.? I am thinking about putting connections under a sheet of scrap Lexan.? Yours seems easier.? Thanks for your go-box photo.
73 KY4XJ Paul
? ?
On Thursday, February 22nd, 2024 at 2:03 PM, mordan42 via groups.io <mordan42@...> wrote:
Hello all, looking for assistance with my POTA to go box, which consists of QMX Rev 1 low band, a screen, an Inovato Quadra box, and a morse key paddle in an Apache case. WSJTX works great on decoding, but when the QMX tries to transmit, I get one dot under VFO indicator and a brief flash of power out meter, then everything reverts not no dots under VFO and AGC meter (Firmware 17 is running). I would include a picture but it happens so quickly, I can't really get it.
My QMX works fine on a PC laptop, so I suspect it's an Inovato Quadra or Debian system setting getting in the way. I'm new to both of those and would greatly appreciate any assistance.
73 de AD5MO
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I'm on my 5th build.? All work and the latest partial SMT and works the same as the others.
My curves are different than Guidos.? I never measure output impedance,? However the?
gain I get is flatter to 30mhz.? I used a 50mW into an attenuator so the source sees
a flatter load.?
Fixture line up used was a Rigol815T, Qbit block amp, step attenuator(HP set to 10db),
DUT(the amp), 30DB Narda?power attenuator, Kaye step attenuator to Rigol input.??
The Qbit amp is a class A video amp flat from .5Mhz to 100Mhz with max undistorted
output of 27dbm.??
Test is done at 9W to avoid saturation . for the amps I have and built 1db compression?
varies from 12W to 13.5W at 13.8V at it terminals.?
The amp will oscillate if the wiring is poor that being th einput coax and output coax
to LPF and load.? Your dealing with 26-28db of gain.
--
Allison
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Post online only,?
direct email will go to a bit bucket.
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I built 3 of V1 type 10W linear amplifier to use with ?my own design carrier board and am very happy with it. I am still using them for my sota/vota activities.Great product!
--
?
73, Barb
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Hi Hans. Glad your problem is (painfully) solved.? I can;t tell you how many times I've got bitten over the years with:
1. early CMOS chips that had no input protection.? They would get damaged if you looked at them the wrong way.? From where I live, I had ab expression, "CMOS loves the summer, CMOS hates the winter."? In anything I design for my own use, I always make sure devices have built-in ESD protection to the extent available.
2. I learned not to get too clever taking advantage of of a device's unusual internal structure that may not be there from multiple vendors.? I once minimized chip count for a 5 v to 10 v level shifter by taking advantage of a 5V CMOS device that could handle 10 volts on its output via a pullup resistor to 10 volts. This was confirmed by the vendor as acceptible use. I was happy for awhile, then I became unhappy when the vendor stopped making the part.? No problem. I said to myself. There are several other vendors making the part.? But it turned out they were all only 5V compatible on their output. So I had to do a redesign with considerably more parts and was considerably unhappy.
-Steve K1RF
------ Original Message ------
Date 2/23/2024 4:36:53 AM
Subject Re: [QRPLabs] #qmx #shipping update
Hi all
GOOD NEWS... (rare, I know)
I carefully followed the mail tracking number with the domestic courier, for the 350 Nexperia BSS84AK I ordered from Istanbul on Tuesday afternoon that shipped on Wednesday. This morning I saw that it had arrived in the cargo depot in town (12km?up the road). So after I delivered the three kids to their schools and kindergarten respectively, I stopped off at the cargo depot and picked up my small package. A little quicker than waiting for them to put it on their next village van in my direction.?
We tested five QMX Rev 3 boards this morning. I changed the Q202 transistor from the factory BSS84 to the new Nexperia BSS84AK, and asked five different people in my team to assemble the boards, with their miscellaneous ESD fetishes... I'm very happy to report that all five worked perfectly!?
My technician has now started replacing the transistors on 345 QMX Rev 3 boards. I placed an order for 650 more of these transistors so we can complete the replacement on the entire batch of 1,000 Rev 3 boards. We are resuming QMX kit shipments today! Problem solved!
I'm still a bit annoyed that there are multiple kinds of BSS84, some with ESD protection and some without. Even Nexperia have a BSS84 with no ESD protection and the BSS84AK with ESD protection. Other parameters are different between the two variants, and with other manufacturers too. I don't get it, why keep moving the goalposts? Isn't life hard enough already... reminded me somehow of Japan, living in Tokyo 2011 after the great?Tōhoku earthquake in March 2011; standing on solid ground was always something kinda fundamental to my existencialism... but with all the daily aftershocks for a year+, the whole place was all jumping all over the place the whole time. And now I can't even rely on my BSS84's...
On Fri, Feb 23, 2024 at 12:37?AM Dave Schmidt < dgschmidt@...> wrote: Wow!? Thanks for the update!? Between new developement, existing support and dealing with supply chain and contract manufacturer's issues, I don't see how you can do it all and still get time to sleep!
Dave
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On 23/02/2024 11:58, Dan Hurd W5DMH wrote: Has anyone tried using a USB to 12v Buck converter to power their QDX? Dan, From 5 volts USB you might get ~300mA at 12 volts? Even if you do not get any QRM from the converter TX would have to be QRP. Maybe feed the PA from 5 volts on another USB socket. Then why use a converter? 5 Volts could power a QDX directly What I'm saying is I do not think it would work:-) 73 Alan G4ZFQ.
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Hi
I have used these
answer is no
- You won't have the required current on transmit
- Too much noise on receive
?
There might be a solution on USB-C s
I am using an Varta power bank (Power Bank Fast Energy Type 57983) for
5 volts to RPi from USB
12 volts to QDX/QMX from USB-C with a special cable (it triggers the USC-C to give 12 Volts)
73 muhsin TA1MHS
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Has anyone tried using a USB to 12v Buck converter to power their QDX??
I would like to plug into my laptop and not have to carry a separate battery for the QDX.?
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Hi all
GOOD NEWS... (rare, I know)
I carefully followed the mail tracking number with the domestic courier, for the 350 Nexperia BSS84AK I ordered from Istanbul on Tuesday afternoon that shipped on Wednesday. This morning I saw that it had arrived in the cargo depot in town (12km?up the road). So after I delivered the three kids to their schools and kindergarten respectively, I stopped off at the cargo depot and picked up my small package. A little quicker than waiting for them to put it on their next village van in my direction.?
We tested five QMX Rev 3 boards this morning. I changed the Q202 transistor from the factory BSS84 to the new Nexperia BSS84AK, and asked five different people in my team to assemble the boards, with their miscellaneous ESD fetishes... I'm very happy to report that all five worked perfectly!?
My technician has now started replacing the transistors on 345 QMX Rev 3 boards. I placed an order for 650 more of these transistors so we can complete the replacement on the entire batch of 1,000 Rev 3 boards. We are resuming QMX kit shipments today! Problem solved!
I'm still a bit annoyed that there are multiple kinds of BSS84, some with ESD protection and some without. Even Nexperia have a BSS84 with no ESD protection and the BSS84AK with ESD protection. Other parameters are different between the two variants, and with other manufacturers too. I don't get it, why keep moving the goalposts? Isn't life hard enough already... reminded me somehow of Japan, living in Tokyo 2011 after the great?Tōhoku earthquake in March 2011; standing on solid ground was always something kinda fundamental to my existencialism... but with all the daily aftershocks for a year+, the whole place was all jumping all over the place the whole time. And now I can't even rely on my BSS84's...
On Fri, Feb 23, 2024 at 12:37?AM Dave Schmidt < dgschmidt@...> wrote: Wow!? Thanks for the update!? Between new developement, existing support and dealing with supply chain and contract manufacturer's issues, I don't see how you can do it all and still get time to sleep!
Dave
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Hi Jerry,
I have built two of these amplifiers and they work flawlessly.
The only thing I can think of is a possible bad contact due to a cold solder joint.
Check the bias currents of the IRF510.
73
Guido? on7ch
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QCX Challenge - February 2024
Hi all,
?
Yes, february has one more day this year, but it's still the shortest month, so it's already time again for the?QCX Challenge, next Monday, February 26th, at 1300Z, 1900Z and 0300Z (Tuesday).
?
See all info here :?
?
Join the discord page in the #qcx-qrp-operation channel to post your QRG or exchange other info, or just have a chat with other QRP Labs friends ...
Just a note:
While the 'contest' aspect of the QCX Challenge is not the main goal, we just want to have some fun with our rigs, right ?
But I want to remember that if you want to take it up as a contest and want to play it fair, each QSO must have the needed exchange,
from the rules? :
Exchange:?true RST, name, rig, power
Some complain about the SST being at the same times, some see it as easy points , but grabbing a few quick SST qso's without the full exchange is not in 'in the spirit of the program' ...
As for that SST, I think there is always enough room in the higher portion of the band (e.g. QSY above 7050 on 40m, above 14060 on 20m etc)
73 es GL,
Luc ON7DQ
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Oleh and other gentlemen,
That's what I found out. Thank you!
The little fella is an amazing piece of work and the support offered here by both Hans and the rest of the QRP Labs group membership is absolutely terrific! Once I stumbled through my first waves of ignorance, everything fell into place and the QDX performed flawlessly. I have never had a radio I built out of the box (off the bench?) work with as little troubleshooting as this one!
And I cannot say enough about the forethought and engineering that went into the creation of this radio. Not to gush too much (impossible!) but after building this kit and watching the many presentations by Hans -- -- I remain astounded at the genius of his work..
..also on the order sheet for the "low band" version of this hoping to catch the magic once more!
As Alistair Sim said in his famous Yuletide recounting in the movie, Scrooge, My sincere gratitude to all!? ? ?
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."
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Your oversensitive MOSFET brings back memories of dealing with very ESD sensitive A/D converters from when I was a design engineer in the 1980's. We were constantly riding the production manager for poor manufacturing yield (infant mortality or failure during burn-in). He resorted to all sorts of weird methods to rein in ESD on the production floor. He was spraying the place down with fabric softener (that just made everything sticky and slippery at the same time) and chasing down people to make sure they had the conductive heel-straps inside their shoes. Finally we figured it out, his group was all wearing company issued lab jackets that were made of synthetic fiber and just moving their arms they generated a few thousand volts.
And yea, we had to go back and put 100k resistor blocks on the data busses at the card edges. The radio that was built in to the device was also generating RFI if there was a bad antenna on the two watt transmitter.
I am excited for my second QMX to be at position #68 on the list.
--
Tisha, AA4HA
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Allison,?
I believe this is the size iron Hans is referring to, in his early Neolithic writings, as being just a little large, but still able to get the job done in a pinch.
I believe Hans found a Weller iron once that had the same characteristics.?
I believe his phrase was " it might be a tight fit. If we can get it close enough and not bump the board, the radiating? heat will free the BAS521.......? Of course this is before the advent of using hot air to remove such small trivial items.
Maybe Hans can reminisce and wax eloquent at the FDIM and let's us know what it was like way back when....
Warmest Regards
James?
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Re: QMX HIGH BAND NO RF OUT AFTER ANOTHER 10 hour WSPR TRANSMISSION
Giuseppe,
If you are convinced that the BS170s have failed, replace them. It is not difficult.
Try to find another nearby Ham or Radio club that can help you with diagnosis and repair, if you feel insecure in doing it yourself.
JZ
On Thu, Feb 22, 2024, 7:36?PM GIUSEPPE < iw8rsb@...> wrote: John, I tried to transmit from home with QMX and listen with the Yaesu FT 817 in CW, the absorption in transmission is low but the CW tone can be heard and the signal is full, in my opinion it's the BS170 transistors that have gone up in smoke , I can't understand how it went from 6W of power to a few mW, I used a wattmeter and an LED meter and there is no RF output, I don't understand what could have happened, I sent an email to Hans but I didn't received no response, everything else about the QMX works great.? Booooòhhhh.........I don't know what to do anymore.? 73 bye
Giuseppe iu8eun
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
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Re: QMX HIGH BAND NO RF OUT AFTER ANOTHER 10 hour WSPR TRANSMISSION
John, I tried to transmit from home with QMX and listen with the Yaesu FT 817 in CW, the absorption in transmission is low but the CW tone can be heard and the signal is full, in my opinion it's the BS170 transistors that have gone up in smoke , I can't understand how it went from 6W of power to a few mW, I used a wattmeter and an LED meter and there is no RF output, I don't understand what could have happened, I sent an email to Hans but I didn't received no response, everything else about the QMX works great.? Booooòhhhh.........I don't know what to do anymore.? 73 bye
Giuseppe iu8eun
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
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#key #qmx QMX Straight Key Mode incorrect
#key
#qmx
Hans,
The standard way to connect a straight key is to connect it to the tip and sleeve. The QMX Straight Key Mode is supposed to do that, but when selecting 'Tip" it does not work and instead the "Ring" is active. To use the standard connections I need to select "Ring". The logic is reversed in the QMX.
Gary
W9TD
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Praising Jeffery Moore W1NC
This wonderful ham found my mistakes and fixed my QCX Rev2 and it works great! ?I highly recommend him if you find yourself over your head while trying to get your Qrp Labs kit working properly! I had a few problems I could not diagnose (some due to a known early Rev2 board problem) and a couple of pieces of loose solder I did not find. Thank you Jeff ? I hope to meet you someday and thank you in person!
Keith N8CEP
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Nice large caliber iron, I'd use it for SMT!? ;)??
--
Allison
------------------
Post online only,?
direct email will go to a bit bucket.
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Wow!? Thanks for the update!? Between new developement, existing support and dealing with supply chain and contract manufacturer's issues, I don't see how you can do it all and still get time to sleep!
Dave
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Barb WB2CBA
ON7DQ Luc
k6whp
Tisha Hayes, AA4HA
KB9NBL
Gary W9TD