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#qsoparty Fun with 40m in QRO QSO Party, report #qsoparty


Hans Summers
 

Hi all

Since the thread on the QRO QSO party somehow got hijacked, here's a new one. Apologies if it is not of interest... 

I was a bit unlucky at 1900Z, I had a reply to my first CQ on 40m immediately (which was not unlucky), from UT2LA/QRP Sergey. I sent his report etc. But then during his over, I had a family interruption... for 45 minutes! I came back at 1951Z and worked HA6VH Geza and E74LZ Meho. After Meho, (and after 2000Z) people kept calling and calling... there were several at once... I QSOed 4L6QL Mike then LZ2GA Georgi, there were still people calling, but I was so so tired and planning to get up early for the 0300Z session so reluctantly I switched off the radio. 

This morning at 0300Z it was 6am local time and everyone was asleep. Even, miraculously and highly uncharacteristically, The Baby. 40m was beautifully quiet at my QTH and very little QSB. I had a long stream of QSOs, most of them with very good signals:

RA3LK Anatol
UA6YH Alex
UA6YX Yuri
UR5EOH Toly
DJ0YI Ben
UA4CDV Vlad
R4PCE Alex
DH2FW Frank
HA0HW Laci (starting 0404Z so just outside the hour). 

No QCXs in any of them :-/   But at least Ian G4GIR made up for that in the 1300Z session yesterday, one of my five 20m QSOs that session. 

Sorry to go on... but this was my first time on air for 1 month since the last QRP Labs QRO QSO party! The QSO parties help get me on air, and remind me what fun I *should* be having if I wasn't so busy :-/   Now I have good enthusiasm for the day! I should do this every morning!

Another question... in case anyone has any ideas... I have a 0-30V, 0-20A linear power supply type RXN-3020D. Purchased new last year. Same ubiquitous design thing, as made by many manufacturers. I power it on, and set it for 20V. Current draw on key-down is somewhere between 4.5A for around 50-60W RF output (including the current consumption of the QCX). *IF* I turned the knobs all the way clockwise the display reads 31.2V. HOWEVER... over the course of an hour of operating, the output voltage drifts downward. I have to keep making adjustments, turning the voltage knob clockwise a bit, to keep the output reading 20V. By the end of an hour's operating, the voltage knob is almost all the way clockwise and the thing can just barely make it past 20V. Any ideas anyone? I ought to open it up probably. But time is so short... 

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


Shane Justice
 

Hans,

That is a lot of good news! I am looking forward to getting my U3S/D kit, the QCX+, as well as the 50W PA kit completed and on the air, so I can join you all. I don't know what propagation will be like, but I look forward to trying it. It may be sometime before I can do so, as I still have to erect an antenna, and I am about 1/4 way through the CW Acadamy intermediate course, so that I can boost my speed of copy to match those who are more practiced/proficient than I.

Do be careful with yourself and make sure you balance work, family and fun- it's no fun to get burned out. 

Thinking about your power supply issue, I only have general comments; 1) make sure you turn down the voltage after your session, just in case the power supply recovers and the voltage returns to 30V, so you don't lose something that is connected that can't tolerate the 30V level. 2) if the voltage does recover, there is something probably in the regulation circuit that is experiencing thermal effects- perhaps the voltage reference, or the comparitor, or even the driver circuitry. 3) if the supply has smarts in it, it could be some issue with the ripple regulation, or over current sensing.

As I am unfamiliar with the power supply you have, I looked up the model number, and found there are A, and D versions of the manuals. Which do you have?

Perhaps some study of the schematic might indicate a troubleshooting starting point.

If you have a thermal camera, or IR thermometer, it will point out a region that is getting hot, and you can zero in on the components in that region to determine if the issue is a design or component flaw.

I wish I could be more assistance to you.

73,
Shane


On Sep 14, 2020 at 22:41, Hans Summers <hans.summers@...> wrote:

Hi all

Since the thread on the QRO QSO party somehow got hijacked, here's a new one. Apologies if it is not of interest... 

I was a bit unlucky at 1900Z, I had a reply to my first CQ on 40m immediately (which was not unlucky), from UT2LA/QRP Sergey. I sent his report etc. But then during his over, I had a family interruption... for 45 minutes! I came back at 1951Z and worked HA6VH Geza and E74LZ Meho. After Meho, (and after 2000Z) people kept calling and calling... there were several at once... I QSOed 4L6QL Mike then LZ2GA Georgi, there were still people calling, but I was so so tired and planning to get up early for the 0300Z session so reluctantly I switched off the radio. 

This morning at 0300Z it was 6am local time and everyone was asleep. Even, miraculously and highly uncharacteristically, The Baby. 40m was beautifully quiet at my QTH and very little QSB. I had a long stream of QSOs, most of them with very good signals:

RA3LK Anatol
UA6YH Alex
UA6YX Yuri
UR5EOH Toly
DJ0YI Ben
UA4CDV Vlad
R4PCE Alex
DH2FW Frank
HA0HW Laci (starting 0404Z so just outside the hour). 

No QCXs in any of them :-/   But at least Ian G4GIR made up for that in the 1300Z session yesterday, one of my five 20m QSOs that session. 

Sorry to go on... but this was my first time on air for 1 month since the last QRP Labs QRO QSO party! The QSO parties help get me on air, and remind me what fun I *should* be having if I wasn't so busy :-/   Now I have good enthusiasm for the day! I should do this every morning!

Another question... in case anyone has any ideas... I have a 0-30V, 0-20A linear power supply type RXN-3020D. Purchased new last year. Same ubiquitous design thing, as made by many manufacturers. I power it on, and set it for 20V. Current draw on key-down is somewhere between 4.5A for around 50-60W RF output (including the current consumption of the QCX). *IF* I turned the knobs all the way clockwise the display reads 31.2V. HOWEVER... over the course of an hour of operating, the output voltage drifts downward. I have to keep making adjustments, turning the voltage knob clockwise a bit, to keep the output reading 20V. By the end of an hour's operating, the voltage knob is almost all the way clockwise and the thing can just barely make it past 20V. Any ideas anyone? I ought to open it up probably. But time is so short... 

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


Hans Summers
 

Hi Shane
 
That is a lot of good news! I am looking forward to getting my U3S/D kit, the QCX+, as well as the 50W PA kit completed and on the air, so I can join you all. I don't know what propagation will be like, but I look forward to trying it. It may be sometime before I can do so, as I still have to erect an antenna, and I am about 1/4 way through the CW Acadamy intermediate course, so that I can boost my speed of copy to match those who are more practiced/proficient than I.

Good luck! I am gradually incrementing my keyer speed every few months. I have it set to 14wpm now. On the assumption people will likely be replying at similar speed, I think I must be improving. Terribly slowly, but improving nonetheless.  
 
Thinking about your power supply issue, I only have general comments; 1) make sure you turn down the voltage after your session, just in case the power supply recovers and the voltage returns to 30V, so you don't lose something that is connected that can't tolerate the 30V level.

I have very good habits in that regard. Don't ask me to list all the terrible incidents, nor even a count of how many incidents there were, until I got to these good habits... 
 
2) if the voltage does recover, there is something probably in the regulation circuit that is experiencing thermal effects- perhaps the voltage reference, or the comparitor, or even the driver circuitry.

The voltage recovers yes... 
 
3) if the supply has smarts in it, it could be some issue with the ripple regulation, or over current sensing.

As I am unfamiliar with the power supply you have, I looked up the model number, and found there are A, and D versions of the manuals. Which do you have?

The full model number is RXN-3020D. 
 
Perhaps some study of the schematic might indicate a troubleshooting starting point.

Probably... I am guilty of the worst kind of person who asks for help... the one who has not exhausted all possible avenues to help himself, before asking help from others. I only plead forgiveness on account of work overload!

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


Shane Justice
 

Hi Hans,

I was looking for the RXN-3020D on the internet. Not sure what's going on with the search engine, but one link went to a PDF of the attached file, which has a schematic for a 30V, 20A power supply that seems to have a front face drawing similar to a RXN-3020D sketch I saw us a four page manual specifically for the 
RXN-3020D.

If you want to pull the cover off and see if the part designations on the board match the drawing, this would be a good starting point.

If so, perhaps we can do some prognosticating about where to look for thermal issues.

73,
Shane


On Sep 15, 2020 at 09:13, Hans Summers <hans.summers@...> wrote:

Hi Shane
 
That is a lot of good news! I am looking forward to getting my U3S/D kit, the QCX+, as well as the 50W PA kit completed and on the air, so I can join you all. I don't know what propagation will be like, but I look forward to trying it. It may be sometime before I can do so, as I still have to erect an antenna, and I am about 1/4 way through the CW Acadamy intermediate course, so that I can boost my speed of copy to match those who are more practiced/proficient than I.

Good luck! I am gradually incrementing my keyer speed every few months. I have it set to 14wpm now. On the assumption people will likely be replying at similar speed, I think I must be improving. Terribly slowly, but improving nonetheless.  
 
Thinking about your power supply issue, I only have general comments; 1) make sure you turn down the voltage after your session, just in case the power supply recovers and the voltage returns to 30V, so you don't lose something that is connected that can't tolerate the 30V level.

I have very good habits in that regard. Don't ask me to list all the terrible incidents, nor even a count of how many incidents there were, until I got to these good habits... 
 
2) if the voltage does recover, there is something probably in the regulation circuit that is experiencing thermal effects- perhaps the voltage reference, or the comparitor, or even the driver circuitry.

The voltage recovers yes... 
 
3) if the supply has smarts in it, it could be some issue with the ripple regulation, or over current sensing.

As I am unfamiliar with the power supply you have, I looked up the model number, and found there are A, and D versions of the manuals. Which do you have?

The full model number is RXN-3020D. 
 
Perhaps some study of the schematic might indicate a troubleshooting starting point.

Probably... I am guilty of the worst kind of person who asks for help... the one who has not exhausted all possible avenues to help himself, before asking help from others. I only plead forgiveness on account of work overload!

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


KEN G4APB
 

On Tue, Sep 15, 2020 at 06:41 AM, Hans Summers wrote:
Another question... in case anyone has any ideas... I have a 0-30V, 0-20A linear power supply type RXN-3020D. Purchased new last year. Same ubiquitous design thing, as made by many manufacturers. I power it on, and set it for 20V. Current draw on key-down is somewhere between 4.5A for around 50-60W RF output (including the current consumption of the QCX). *IF* I turned the knobs all the way clockwise the display reads 31.2V. HOWEVER... over the course of an hour of operating, the output voltage drifts downward. I have to keep making adjustments, turning the voltage knob clockwise a bit, to keep the output reading 20V. By the end of an hour's operating, the voltage knob is almost all the way clockwise and the thing can just barely make it past 20V. Any ideas anyone? I ought to open it up probably. But time is so short... 

Hi Hans, the user manual describes a ‘restricted current mode’, maybe you have inadvertently set it. Also, there is a warning that high levels of RF can affect it. Maybe you need to turn the psu off and on again at the mains to reset it and put some ferrite on the input and output leads???

 

73 Ken G4APB