Date   

Re: No sidetone on QCX #qcx #sidetone

 

Howard:

I do get sidetone when the QCX is in Keyer Setup mode.  The sidetone is not heard once the QCX is actually transmitting CW.
--
73, Bernie, VE3FWF
(most typos in this message have been generated by highly sophisticated auto-correction software)


QCX acceptable load mismatch?

Johan Bodin
 

Hi,

is there any knowledge/experience about how much abuse the QCX PA can withstand without damage? If a low loss SWR meter is used, the impedance seen by the PA will deviate wildly from the 50+j0 ohm target while searching for a perfect match with an antenna tuner. I am currently using a -6dB resistive SWR bridge (three 50 ohm resistors + a detector) while tuning so the worst case load seen by the QCX goes from 33 to 100 ohms when the load at the bridge output goes from shorted to open. Can I assume that this is safe?

My Mini is still alive and well but the lack of PA protection makes me a little worried. I just want to prevent failure in the field when messing around with makeshift antennas :)

73
SM6LKM


Re: No sidetone on QCX #qcx #sidetone

howard winwood G4GPF
 




I changed Q6 as I thought that might be the problem.  And while I was at it, I updated the firmware to 1.07a. There is sidetone coming from the micro on R59  according to the scope.


if you see the sidetone at R59, you then need to trace it through IC8b (pin 7), IC8a (pin 1),IC9b (pin7), IC9a (pin 1) via volume pot and Q7 to IC10b (pin7), IC10a (pin 1) to headphones.
The pins quoted are the output pins on each op amp


Re: Another Successful QCX-Mini Build

Albert Tatlock's Greatest Hits - Vol 1
 

On Wed, Apr 7, 2021 at 01:01 PM, Arv Evans wrote:
Wind power from the beans?  8-)
Exactly ;-)

https://www.youtube.com/watch?v=FXHkFZ-nG4Y


Re: Another Successful QCX-Mini Build

Arv Evans <arvid.evans@...>
 

Wind power from the beans?  8-)

_._


On Wed, Apr 7, 2021 at 1:58 PM Jesus Christ on Toast via groups.io <andyfoad=rocketmail.com@groups.io> wrote:
On Wed, Apr 7, 2021 at 12:19 PM, Hans Summers wrote:
I know people have their QCX-minis all nice and ready to go with charged batteries etc., and what do I do here when there's no power, I just eat beans.
Time to invest in wind power ;-)


Re: Another Successful QCX-Mini Build

Albert Tatlock's Greatest Hits - Vol 1
 

On Wed, Apr 7, 2021 at 12:19 PM, Hans Summers wrote:
I know people have their QCX-minis all nice and ready to go with charged batteries etc., and what do I do here when there's no power, I just eat beans.
Time to invest in wind power ;-)


Re: Another Successful QCX-Mini Build

Arv Evans <arvid.evans@...>
 

Hans

Do I sense a near-future tutorial on how to stage one's QRPLabs
transceiver for emergency use? 

Similar problem solved here by having a fully charged 12V wet cell
in the garden tractor.  Also have a string of salvaged yard-light solar
cells that keep 4 Li-ion cells up to 12V.  These are mostly ignored 
and only used infrequently when I need a quiet power source for
high-gain audio experimentation.

Arv
_._




On Wed, Apr 7, 2021 at 1:19 PM Hans Summers <hans.summers@...> wrote:
Hi Jody

Thanks for the nice feedback and yes, the test jig is seeing plenty of action these days, now into its second 1000-batch ( https://youtu.be/xb_ZmPx7Py4 ). Have fun!

I managed to get a rare bit of operating time in today myself, which was fun here too. 

The day did not get off to a good start, when the power went off at about 7am. When the rest of the team arrived for work at 8:30am, I discovered everyone already knew about this 7am-noon planned outage except me, nobody ever tells me anything. Had I known I could have put the 'phone on charge overnight, rather than being nearly empty (12% battery). 

So what can a wannabe radiophile like me do, with no electricity? I ate some breakfast. Unwrapped and read the last two issues of RadCom, which unmysteriously had arrived only 1 day apart, last week (note: unmysteriously because here in the farthest-outer-reaches-of-outer-nowhere-at-all much stranger things happen, indeed it is not far short of a miracle if a RadCom turns up at all). Then I re-read SPRAT, which was also a recent beneficiary of the postal services evident spontaneous burst of abnormal efficiency. I tidied the workbench. I read some old article papers from 2008. I took a power nap (anti-pun unintended). 

At some point the phone charge reached 4% and an existential crisis therefore approached criticality. The XYL had taken the car to town and so plugging it in to the car was not an option either. Nobody had a power bank. I walked to the supermarket, the supermarket didn't have a power bank either (optimistically I had hoped they might and hopelessly optimistically, that it might arrive at least partially charged). The kids iPads were at 100% charge but without connectivity, and rigging some USB sockets from my old PC case wiring harness back to back, didn't help since the iPad seems not to want to deliver power out of its charging connector as a PC might. 

Then I recalled from my 2017 GSM Data logger product development, the small 12V 10W solar panel out on the roof, long-forgotten and unloved. I found the other end of the cable and tested with the DVM, sure enough ~19V unloaded, still working... I found a project with a 7805 in it and enough wiring that I could cut it out and have some wires to twist the wires from the solar panel on, and twist the wires from the old PC wiring harness with the USB sockets. 5V! Hooray, and yes, the phone started charging up. Crisis almost appeared to be averted until a few minutes later the smell of burning was rapidly succeeded by the sound of yelling when I probed with my finger to find the tab of the 7805 red-hot. Of course, I forgot, you drop the volts like that, you dissipate lots of heat, oops... so a quick hunt for a scrap piece of metal with a suitable hole in it and a nut and bolt and that problem was solved too. 

By then 12 noon had rocked round and the power still did not come back at the promised prescribed time. In fact things got worse because the tap water stopped too. The over-optimistic walk to the supermarket had not been entirely fruitless since I found some cans of Heinz baked beans which are of course usual back in Blighty but a rare find in these parts. So I went and ate a can of cold Heinz baked beans for lunch which is exactly my favourite way of eating beans even when there isn't an unforgivable lack of power. 

While munching delicious Heinz beans I started to feel despondent yet again about being such a bad radio amateur, I would be of absolutely no use in any emergency, I know people have their QCX-minis all nice and ready to go with charged batteries etc., and what do I do here when there's no power, I just eat beans. Then I sat upright and thought, what am I NOT thinking! I have my 12V 10W panel on the roof, and I have my QCX+! So I rushed upstairs and ripped the wires off my MacGyver'ed phone charger, and screwed them into a 2.1mm connector... and was calling CQ on 14012 within 5 minutes. 

There was a horrible thump on key-down as the solar panel voltage (and hence QCX+ supply voltage) dropped from near 18V down to about 10V. Even in the bright sunlight there's no way that panel is producing the rated 10W. Maybe it's covered in dirt up there, who knows. I estimate at 10V the QCX+ was producing maybe somewhere around three watts of output power. I had five answers to my CQ's in an hour of operating, best DX Ken G3OCA at 2933km. Not bad at all and lots of fun. 

The power didn't come back until 3:30pm. But every cloud has a silver lining.

73 Hans G0UPL
http://qrp-labs.com



On Wed, Apr 7, 2021 at 8:01 PM Jody - K3JZD <k3jzd.jody@...> wrote:
I finished building my 80m Rev 2 QCX-Mini just in time for this month's Spartan Sprint.  The build was picture perfect - the alignment went as expected.   The Quality Control on the Minis is now great.  Very sensitive receiver, and I was able to work everyone that I heard.during the Spartan Sprint event. 

With the LCD back light turned off, I was able to run the whole two hours without consuming my small lightweight 500mAH LiPo battery pack.  And that was with me calling CQ repeatedly using the QCX-Mini memory keying features, leaving just a 10 second delay between my transmissions. The SMD based QCX-Mini is much easier on batteries than my through-hole component based 40m QCX and 20m QXC+ units.are.  Since 80m may become less attractive as we head into the Summer months, I guess it is now time for me to order a 40m QCX-Mini to obtain that better battery life whenever I am using 40m.

Jody - K3JZD

 


Re: A simple QCX AGC #mods #qcx

Jim AJ8S
 

I decided to order the rev 2 boards also.....


Re: No sidetone on QCX #qcx #sidetone

Russ AB6MU
 

Hi Bernie,

Have you watched the Youtube video that Hans posted on debugging the QCX? If not, you may find it helpful.

Debugging QCX issues, using cheap pocket scope, DVM or built-in DVM. With 40m QSO at the end

Russ


Re: Another Successful QCX-Mini Build

Hans Summers
 

Hi Jody

Thanks for the nice feedback and yes, the test jig is seeing plenty of action these days, now into its second 1000-batch ( https://youtu.be/xb_ZmPx7Py4 ). Have fun!

I managed to get a rare bit of operating time in today myself, which was fun here too. 

The day did not get off to a good start, when the power went off at about 7am. When the rest of the team arrived for work at 8:30am, I discovered everyone already knew about this 7am-noon planned outage except me, nobody ever tells me anything. Had I known I could have put the 'phone on charge overnight, rather than being nearly empty (12% battery). 

So what can a wannabe radiophile like me do, with no electricity? I ate some breakfast. Unwrapped and read the last two issues of RadCom, which unmysteriously had arrived only 1 day apart, last week (note: unmysteriously because here in the farthest-outer-reaches-of-outer-nowhere-at-all much stranger things happen, indeed it is not far short of a miracle if a RadCom turns up at all). Then I re-read SPRAT, which was also a recent beneficiary of the postal services evident spontaneous burst of abnormal efficiency. I tidied the workbench. I read some old article papers from 2008. I took a power nap (anti-pun unintended). 

At some point the phone charge reached 4% and an existential crisis therefore approached criticality. The XYL had taken the car to town and so plugging it in to the car was not an option either. Nobody had a power bank. I walked to the supermarket, the supermarket didn't have a power bank either (optimistically I had hoped they might and hopelessly optimistically, that it might arrive at least partially charged). The kids iPads were at 100% charge but without connectivity, and rigging some USB sockets from my old PC case wiring harness back to back, didn't help since the iPad seems not to want to deliver power out of its charging connector as a PC might. 

Then I recalled from my 2017 GSM Data logger product development, the small 12V 10W solar panel out on the roof, long-forgotten and unloved. I found the other end of the cable and tested with the DVM, sure enough ~19V unloaded, still working... I found a project with a 7805 in it and enough wiring that I could cut it out and have some wires to twist the wires from the solar panel on, and twist the wires from the old PC wiring harness with the USB sockets. 5V! Hooray, and yes, the phone started charging up. Crisis almost appeared to be averted until a few minutes later the smell of burning was rapidly succeeded by the sound of yelling when I probed with my finger to find the tab of the 7805 red-hot. Of course, I forgot, you drop the volts like that, you dissipate lots of heat, oops... so a quick hunt for a scrap piece of metal with a suitable hole in it and a nut and bolt and that problem was solved too. 

By then 12 noon had rocked round and the power still did not come back at the promised prescribed time. In fact things got worse because the tap water stopped too. The over-optimistic walk to the supermarket had not been entirely fruitless since I found some cans of Heinz baked beans which are of course usual back in Blighty but a rare find in these parts. So I went and ate a can of cold Heinz baked beans for lunch which is exactly my favourite way of eating beans even when there isn't an unforgivable lack of power. 

While munching delicious Heinz beans I started to feel despondent yet again about being such a bad radio amateur, I would be of absolutely no use in any emergency, I know people have their QCX-minis all nice and ready to go with charged batteries etc., and what do I do here when there's no power, I just eat beans. Then I sat upright and thought, what am I NOT thinking! I have my 12V 10W panel on the roof, and I have my QCX+! So I rushed upstairs and ripped the wires off my MacGyver'ed phone charger, and screwed them into a 2.1mm connector... and was calling CQ on 14012 within 5 minutes. 

There was a horrible thump on key-down as the solar panel voltage (and hence QCX+ supply voltage) dropped from near 18V down to about 10V. Even in the bright sunlight there's no way that panel is producing the rated 10W. Maybe it's covered in dirt up there, who knows. I estimate at 10V the QCX+ was producing maybe somewhere around three watts of output power. I had five answers to my CQ's in an hour of operating, best DX Ken G3OCA at 2933km. Not bad at all and lots of fun. 

The power didn't come back until 3:30pm. But every cloud has a silver lining.

73 Hans G0UPL
http://qrp-labs.com



On Wed, Apr 7, 2021 at 8:01 PM Jody - K3JZD <k3jzd.jody@...> wrote:
I finished building my 80m Rev 2 QCX-Mini just in time for this month's Spartan Sprint.  The build was picture perfect - the alignment went as expected.   The Quality Control on the Minis is now great.  Very sensitive receiver, and I was able to work everyone that I heard.during the Spartan Sprint event. 

With the LCD back light turned off, I was able to run the whole two hours without consuming my small lightweight 500mAH LiPo battery pack.  And that was with me calling CQ repeatedly using the QCX-Mini memory keying features, leaving just a 10 second delay between my transmissions. The SMD based QCX-Mini is much easier on batteries than my through-hole component based 40m QCX and 20m QXC+ units.are.  Since 80m may become less attractive as we head into the Summer months, I guess it is now time for me to order a 40m QCX-Mini to obtain that better battery life whenever I am using 40m.

Jody - K3JZD

 


No sidetone on QCX #qcx #sidetone

 

There is no sidetone but only a slight hum  and key click  when keying the QCX.  This is a new fault which may have been caused by accidentally keying the rig without an antenna for about 2 seconds.  
 

I searched the archives but nothing came up regarding this problem.

The QCX sounds fine on the air and the RX is OK as well.

I changed Q6 as I thought that might be the problem.  And while I was at it, I updated the firmware to 1.07a. There is sidetone coming from the micro on R59  according to the scope.


Perhaps 🤔 the RX/TX transistor  Q5  is the problem?    I hate to change parts without understanding  the root cause.

 

Next  step suggestions most welcome.


73, Bernie, VE3FWF
(most typos in this message have been generated by highly sophisticated auto-correction software)


Re: 50W QRPLabs amplifier build troubleshooting #50w #troubleshooting

Ron Carr
 

Looking at the graph on page 67 ( or section 8.1 ) 10 watts at 13 volts is not all that low for the 80 meter version at 13 volts. The way to get more power out of this amp is to increase the supply voltage.


Re: 50W QRPLabs amplifier build troubleshooting #50w #troubleshooting

V Z
 

Thanks, Geoff, 

please don't take it as if I go around crushing MOSFETs right and left, and then pining them to my wall collection. Thank for the word of caution :) Mom, I was not inhaling.

Vlad


Re: QCX Mini v2 and Audio Distortion as RF/Voltage grows

Roney Monte
 

Thanks Steve/Howard/Arv/Ron, FB!

I understand your descriptions to each step of circuit verification.

Tomorrow I'll carefully follow your tricks, using the scope and getting more observations. Thats a job to be done slowly.

I will also do the practice mode to test the audio side tone without RF.

I'm in a lock-down area, so I generally have access to the LAB about 2 times a week.
Hope to get data and understand the paths in the circuit. So I will bring new data.

73
Roney


Re: Another Successful QCX-Mini Build

Curt wb8yyy
 

Jody

Wonderful report. Were you on last evening and what were you using as an antenna?

I had my qcx maxi on 80m last evening, it was more swamped than previous use with volume at minimum, using 80m efhw. I see Hans has posted resistor mods in an app note I will try. With a smaller field antenna, perhaps its fine as is. 

I do have a 20m mini on order. For 40m I have a SW40 available. 

Enjoy

73 Curt wb8yyy


Another Successful QCX-Mini Build

Jody - K3JZD
 

I finished building my 80m Rev 2 QCX-Mini just in time for this month's Spartan Sprint.  The build was picture perfect - the alignment went as expected.   The Quality Control on the Minis is now great.  Very sensitive receiver, and I was able to work everyone that I heard.during the Spartan Sprint event. 

With the LCD back light turned off, I was able to run the whole two hours without consuming my small lightweight 500mAH LiPo battery pack.  And that was with me calling CQ repeatedly using the QCX-Mini memory keying features, leaving just a 10 second delay between my transmissions. The SMD based QCX-Mini is much easier on batteries than my through-hole component based 40m QCX and 20m QXC+ units.are.  Since 80m may become less attractive as we head into the Summer months, I guess it is now time for me to order a 40m QCX-Mini to obtain that better battery life whenever I am using 40m.

Jody - K3JZD

 


Re: QCX Mini v2 and Audio Distortion as RF/Voltage grows

Ronald Taylor
 

Steven/Roney, actually the voltages on IC9 are correct. IC9B is DC coupled to IC8 and has roughly the same voltages present (pins 5,6,&7) as does IC8A (pins 1,2&3) and all previous stages back to IC5. Roughly 2.5 volts is the expected reading on IC9B. The only IC with bias voltages approximately half the 12v supply are those on IC10. IC9A is capacitively coupled in and out and is separately biased via a 750K ohm resistor from the 5 volt supply, so roughly 5 volts on IC9 pins 1,2&3 is also normal. 

It does sound like a stage is going into oscillation at some voltage though. As Arv mentioned earlier, you need to use your scope to look for the stage that's oscillating. Also, you should check all the bias voltages on all the op amps. Be aware that the voltages in the chart are taken with the internal DVM and the low impedance of that device tend to load down some of the readings. Using your external DVM you should see roughly 2.5 volts bias on all op amps prior to IC9A. It is also possible to have a stage in oscillation but the voltages look OK. Finally, it is possible you are getting RF back into the audio circuits. You might try transmitting in practice mode to see if the problem still exists with no RF present ... ie just an audio problem. Good luck

73 ... Ron

On Wed, Apr 7, 2021 at 4:45 AM Steven Dick <sbdick@...> wrote:
IC9 pins 5,6,7 are too low.  They should be close to half of the +12V supply. You didn't list voltages for IC8, which could be abnormal making voltages at IC9 pins 5.6.7 too low.
This abnormal condition needs to be looked at more closely. Check all solder joints around this area and possible shorts.
DC levels need to be fixed, but perhaps one of the op amps is oscillating and the nature of the oscillation changes as a function of supply voltage. The sidetone frequency should not change with power supply voltage changes. All the frequencies you list are not audible sidetone frequencies - much too high.

------ Original Message ------
From: "Roney Monte" <roneymonte@...>
Sent: 4/6/2021 6:38:15 PM
Subject: Re: [QRPLabs] QCX Mini v2 and Audio Distortion as RF/Voltage grows

I measured a square wave @ 41.84 KHz in PAD9 "Sidetone" while TX.
I measured a saw wave @ 12.12 KHz in PAD6 "Audio 1" while TX.
I measured a saw wave @ 16.00 KHz in PAD3 "AF Out" while TX.
I measured a saw wave @ 16.00 KHz in PAD12 "SPK" while TX.

I measured a weird distorted square wave @ 41.91 KHz at PAD5 "Audio 2" near R59, when running 12.0V
obs: This same square wave, when running at 7.0V show the stable squares without distortion.

Some IC :

IC10 pin1 = 6.13V                    IC10 pin8 = 12.0V
IC10 pin2 = 6.13V                    IC10 pin7 = 6.13V
IC10 pin3 = 6.13V                    IC10 pin6 = 6.13V
IC10 pin4 = 0V                   IC10 pin5 = 6.13V

IC9 pin1 = 5.27V                    IC9 pin8 = 12.0V
IC9 pin2 = 4.27V                    IC9 pin7 = 2.63V
IC9 pin3 = 4.92V                    IC9 pin6 = 2.61V
IC9 pin4 = 0V                   IC9 pin5 = 2.61V

It seems that some pin voltages are not expected as I read in page 109 from Manual 1.05.

I hope to get more tricks to try to follow.
Thanks
Roney

Virus-free. www.avast.com


Re: not recieved

terry schulz
 

sorry for being a little anxious thanks terry

On Wednesday, April 7, 2021, 07:50:01 AM PDT, Hans Summers <hans.summers@...> wrote:


Hi Terry

"Collecting" is normal for a few days, because the packages must be carried 250km by road via various FedEx/TNT agents to get from my QTH to the nearest TNT depot which is in the city of Izmir. This is always the case. It shows "Collecting" for a few days until it gets to Izmir because these agents are outside the tracking systems. Don't worry about it. 

For future issues regarding shipping please contact me off-list. 

73 Hans G0UPL
http://qrp-labs.com

On Wed, Apr 7, 2021 at 5:36 PM terry schulz <terry.schulz@...> wrote:
might be another problem two shipment numbers the same I provided a pdf below the shipment numbers are the same and is still being collected thanks terry

On Tuesday, April 6, 2021, 03:47:26 AM PDT, Mont Pierce KM6WT <de.km6wt@...> wrote:


On Tue, Apr 6, 2021 at 03:26 AM, Hans Summers wrote:
I already did, and I also sent Terry a new replacement board yesterday, to cover the ahem, err, obviously totally unlikely scenario where TNT don't find the original shipment...
As always, your customer service is the BEST !!!


73,
km6wt


Re: not recieved

Hans Summers
 

Hi Terry

"Collecting" is normal for a few days, because the packages must be carried 250km by road via various FedEx/TNT agents to get from my QTH to the nearest TNT depot which is in the city of Izmir. This is always the case. It shows "Collecting" for a few days until it gets to Izmir because these agents are outside the tracking systems. Don't worry about it. 

For future issues regarding shipping please contact me off-list. 

73 Hans G0UPL
http://qrp-labs.com

On Wed, Apr 7, 2021 at 5:36 PM terry schulz <terry.schulz@...> wrote:
might be another problem two shipment numbers the same I provided a pdf below the shipment numbers are the same and is still being collected thanks terry

On Tuesday, April 6, 2021, 03:47:26 AM PDT, Mont Pierce KM6WT <de.km6wt@...> wrote:


On Tue, Apr 6, 2021 at 03:26 AM, Hans Summers wrote:
I already did, and I also sent Terry a new replacement board yesterday, to cover the ahem, err, obviously totally unlikely scenario where TNT don't find the original shipment...
As always, your customer service is the BEST !!!


73,
km6wt


Re: not recieved

terry schulz
 

my address is Terry Schulz, 822 north 16th st., San Jose California 95112 thanks terry

On Wednesday, April 7, 2021, 07:36:13 AM PDT, terry schulz <terry.schulz@...> wrote:


might be another problem two shipment numbers the same I provided a pdf below the shipment numbers are the same and is still being collected thanks terry

On Tuesday, April 6, 2021, 03:47:26 AM PDT, Mont Pierce KM6WT <de.km6wt@...> wrote:


On Tue, Apr 6, 2021 at 03:26 AM, Hans Summers wrote:
I already did, and I also sent Terry a new replacement board yesterday, to cover the ahem, err, obviously totally unlikely scenario where TNT don't find the original shipment...
As always, your customer service is the BEST !!!


73,
km6wt

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