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Might it be time to step away from the radio for a bit ? ;-)

 

I actually had my first anxiety dream involving amateur radio: I dreamed that I toasted the finals in my QCX...

--
Julian, N4JO.

Daniel Conklin
 

Look in the bright side. At least, in your dream you knew what you toasted. So you can fix it in your dreams.

Fri, Jul 3, 2020 at 02:31 PM, Julian N4JO wrote:

I actually had my first anxiety dream involving amateur radio: I dreamed that I toasted the finals in my QCX...

--
Julian, N4JO.

 
--
73, Dan - W2DLC

Mike Besemer - WM4B
 

Yeah… and at $0.45 each, a pretty affordable disaster.  That kind of anxiety I can deal with. 

 

Mike

WM4B

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Daniel Conklin
Sent: Friday, July 3, 2020 5:56 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Might it be time to step away from the radio for a bit ? ;-)

 

Look in the bright side. At least, in your dream you knew what you toasted. So you can fix it in your dreams.

Fri, Jul 3, 2020 at 02:31 PM, Julian N4JO wrote:

I actually had my first anxiety dream involving amateur radio: I dreamed that I toasted the finals in my QCX...

--
Julian, N4JO.


 
--
73, Dan - W2DLC

dl2arl@...
 

Hi!
toasting the BS170 is not an option. Really! They might go south because of some static discharges on a mountain top (a Zenner Diode or some other surge protectors at the output would take care of this), but toasting them would imply doing something very, very wrong.

I have taken some pain and also found some pleasure by trying to understand the Nathan O. Sokal, WA1HQC writings found on the internet concerning the classE amplifiers and it was worth! YESS!
I also learned a lot from KD1JV and his ATS&MTR rigs that all have classE amplifiers with BS170 transistors.

Bottom line is that if you set them working right (take a look at the "SoftLanding.jpg image attached) and you do not push your ambitions beyond 3 or 4W output from a 13,8V supply, you have no chance of toasting those transistors even if you transmit in the bottom of your trousers instead of a grown-up antenna. In normal operation the transistors do not get warm at all: looking at the QCX with an IR camera, the things that show up hottest are (besides of the processor) the ferrite beads of the low pass filter (mainly the first one after the PA = L3).

Having still had a bad feeling I even ordered some heat-sinks with fancy thermo-glue pads from the remote BY land, but because they did not yet reach me, I found an old brass screw, 8mm thick (M8) and some 20mm long, decapitated it so that only the thread remained and cut with a saw 1/4 of it out (refine the raw cut with a jewler's file). It is no longer a screw now, but something like a 3/4 of a sausage where 1/4 of it  is missing: lengthwise.

Filling the 1/4 gap with some fast curing epoxy and holding the sausage over the transistors will give you the fanciest heat sink you can get, but it will be not worth the trouble. If you get those finals working in their soft landing zone and care for a decent antenna, they will have no reason to heat up at all.

Speaking about the glue to be used... well there are proud special-thermo-glues out there to buy for much'o $, but what for? If there will be a weak link in the heat transmission line between the transistors and the heat sink, this will not be the thin glue fringe between the plastic housing and the heat sink, but the thick plastic housing itself. So why worry?

By the way: I did pair the transistors, well knowing that by being FETs and not bi-polar transistors they will have less thermal run-away issues. Nevertheless, I do take pride having done that and hope that pairing the transistors helps keeping the current flowing trough them even. If this is not taken care of, it's like with the horses in front of a carriage: the best, the hardest working take the most beating. Your mileage might vary, but  pairing them is not a big deal. There is an article on this issue related to the SoftRock rigs out there in the net.

And if this all does not work... as Mike states above my message... at $0.45 each:  why worry? Worry yes, but worry not to spoil the PCB while replacing the transistors, especially if they have been heavily glued to some fancy but needless heat sink gimmik. I read of some wisely providing the transistors with solder-free replacement sockets. This is also not an option for me, because it needlessly increases the reactance of the connection. Wisely used, the finals will last longer than the microprocessor used. At least, the processor sticks in a socket.

I dreamed lately that the finals in my QCX+ froze stiff because nobody was answering my CQs. What about THIS dream of mine? LOL

Wish you all the best 73, Razvan DL2ARL

 

Yes, I suppose I could Daniel - if I had control over them..

And if I DID have control over my dreams, I can assure you it wouldn't be the transistors that were smokin' hot...

Julian N4JO.

On 7/3/2020 4:56 PM, Daniel Conklin wrote:
Look in the bright side. At least, in your dream you knew what you toasted. So you can fix it in your dreams.

Fri, Jul 3, 2020 at 02:31 PM, Julian N4JO wrote:
I actually had my first anxiety dream involving amateur radio: I dreamed that I toasted the finals in my QCX...

--
Julian, N4JO.

 
--
73, Dan - W2DLC

 

Well the point is really that anything I've ever studied really intensely has found its way into my dreams at one point or another: embedded software, piloting an aircraft, foreign languages... one or two blondes in my past...

I'm surprisde that Morse code hasn't found its way there yet; just a matter of time, I would imagine.

Julian, N4JO

On 7/3/2020 5:00 PM, Mike Besemer - WM4B wrote:

Yeah… and at $0.45 each, a pretty affordable disaster.  That kind of anxiety I can deal with. 

 

Mike

WM4B

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Daniel Conklin
Sent: Friday, July 3, 2020 5:56 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Might it be time to step away from the radio for a bit ? ;-)

 

Look in the bright side. At least, in your dream you knew what you toasted. So you can fix it in your dreams.

Fri, Jul 3, 2020 at 02:31 PM, Julian N4JO wrote:

I actually had my first anxiety dream involving amateur radio: I dreamed that I toasted the finals in my QCX...

--
Julian, N4JO.


 
--
73, Dan - W2DLC

 

"I dreamed lately that the finals in my QCX+ froze stiff because nobody was answering my CQs."

Well now, Razvan, that's way worse!

But not, it's not the cost, it's just that the mind likes to conjour up things to worry about sometimes, and logic has nothing to do with it!

Julian, N4JO.

On 7/3/2020 6:33 PM, dl2arl@... wrote:
Hi!
toasting the BS170 is not an option. Really! They might go south because of some static discharges on a mountain top (a Zenner Diode or some other surge protectors at the output would take care of this), but toasting them would imply doing something very, very wrong.

I have taken some pain and also found some pleasure by trying to understand the Nathan O. Sokal, WA1HQC writings found on the internet concerning the classE amplifiers and it was worth! YESS!
I also learned a lot from KD1JV and his ATS&MTR rigs that all have classE amplifiers with BS170 transistors.

Bottom line is that if you set them working right (take a look at the "SoftLanding.jpg image attached) and you do not push your ambitions beyond 3 or 4W output from a 13,8V supply, you have no chance of toasting those transistors even if you transmit in the bottom of your trousers instead of a grown-up antenna. In normal operation the transistors do not get warm at all: looking at the QCX with an IR camera, the things that show up hottest are (besides of the processor) the ferrite beads of the low pass filter (mainly the first one after the PA = L3).

Having still had a bad feeling I even ordered some heat-sinks with fancy thermo-glue pads from the remote BY land, but because they did not yet reach me, I found an old brass screw, 8mm thick (M8) and some 20mm long, decapitated it so that only the thread remained and cut with a saw 1/4 of it out (refine the raw cut with a jewler's file). It is no longer a screw now, but something like a 3/4 of a sausage where 1/4 of it  is missing: lengthwise.

Filling the 1/4 gap with some fast curing epoxy and holding the sausage over the transistors will give you the fanciest heat sink you can get, but it will be not worth the trouble. If you get those finals working in their soft landing zone and care for a decent antenna, they will have no reason to heat up at all.

Speaking about the glue to be used... well there are proud special-thermo-glues out there to buy for much'o $, but what for? If there will be a weak link in the heat transmission line between the transistors and the heat sink, this will not be the thin glue fringe between the plastic housing and the heat sink, but the thick plastic housing itself. So why worry?

By the way: I did pair the transistors, well knowing that by being FETs and not bi-polar transistors they will have less thermal run-away issues. Nevertheless, I do take pride having done that and hope that pairing the transistors helps keeping the current flowing trough them even. If this is not taken care of, it's like with the horses in front of a carriage: the best, the hardest working take the most beating. Your mileage might vary, but  pairing them is not a big deal. There is an article on this issue related to the SoftRock rigs out there in the net.

And if this all does not work... as Mike states above my message... at $0.45 each:  why worry? Worry yes, but worry not to spoil the PCB while replacing the transistors, especially if they have been heavily glued to some fancy but needless heat sink gimmik. I read of some wisely providing the transistors with solder-free replacement sockets. This is also not an option for me, because it needlessly increases the reactance of the connection. Wisely used, the finals will last longer than the microprocessor used. At least, the processor sticks in a socket.

I dreamed lately that the finals in my QCX+ froze stiff because nobody was answering my CQs. What about THIS dream of mine? LOL

Wish you all the best 73, Razvan DL2ARL

Daniel Conklin
 

Morse is a language, and if it finds its way into your dreams, then that's also a good sign that you are acquiring it. I still remember hearing Morse code every time the wind blew through my drafty house.
--
73, Dan - W2DLC

 

Well Dan it's not in my dreams yet, but I am now hearing "phantom Morse" -  incorrectly detecting Morse in other sounds - and I'll assume that's a good thing too :-)

Actually, I am just beginning to break over the threshold into hearing complete "molecular" sound signatures rather than hearing a number of dits and dahs. As I have a focus problem (the dreaded ADD, I think) much of my purposeful learning effort uses the "immersion" technique: having Morse patterns playing in the background while I'm doing something else. That seems to be working, as I'll hear a sound and say "oh, that was an L", or a Y, or whatever. I'm even getting to the point where I hear U and V as sound patterns, not two or three dits followed by a dah, and so on. Setting my app to 25WPM character rate per guidance received has helped enourmously, even if I'm struggling to get a words rate of 8. Farnsworth is my friend.

"I still remember hearing Morse code every time the wind blew through my drafty house."

"You will be visited before this night is done by the spirits of three SK's... "

Julian N4JO.

On 7/3/2020 9:30 PM, Daniel Conklin wrote:
Morse is a language, and if it finds its way into your dreams, then that's also a good sign that you are acquiring it. I still remember hearing Morse code every time the wind blew through my drafty house.
--
73, Dan - W2DLC