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Hints for winding T1 in QCXs

Jim W7EED
 

Hello everyone,

A very common theme in this forum is the difficulty of winding T1 for the QCX.  I have wound quite a few now (although none for 60 or 80 meters) and I have come up with what I believe is a much easier way.

Rather than winding as described in the assembly instructions, I install T1 with just Secondary 3 wound on the core.  Pack it on the core so that it occupies about 180° but don’t allow turns to overlap.  That's not possible on the lower bands; just do it neatly.  Insert the untinned leads through holes #1 and #2.  Hold the core tightly against board and pull the leads on the other side taut with a pair of needle nose pliers and cut so that about 1/8” of each protrudes.  Remove T1 and tin the two leads for about ¼ inch using your soldering iron.  Reinstall T1 and solder.  Pretinning the leads allows the solder to flow through the holes to create a solder minescus on both the top and bottom sides of the board.  Open or "cold" solder joints are virtually impossible to have when this is done.  Here is a photo of a QCX-40 with just Secondary 3 on T1:



I wind Secondary 3 with the lead on the left in the photo on the outside of the core (pad #1).  I refer to it as the “start.”  I then tin (1/4 inch) and solder a short length of wire to pad #5 (a little longer than required to complete Secondary 1).  Since that end will be the “start,” I wind it through and under the core and come out on the “pad #1 side” of the core.  Think of it as winding towards pad #1.  I use tweezers during this step.  I insert the wire through pad #6 after the required number of turns, pull taut, cut and remove.  Tin for about ¼ inch as before.  Reinsert and solder to the pad.  Since that was so much fun, you can do it two more times!  After you're done, it will look like this:


I also strongly suggest that T1 be the first component installed on the board.  It's a lot easier to wind without all of the clutter around it.  After that, just proceed with the assembly as stated in the instructions.

I hope I didn’t make it sound confusing; I am NOT a technical writer!  There’s really no right way, just a way that works for you.  I found this method works for me.

By the way, the question of solder has come up.  I use Sn63/Pb37 rosin core solder (Kester 24-6337-0010), .020 inch diameter.  I have a Weller Soldering Station and I use a small wedge tip at 700°F.

Good luck and have fun!

--
73,
Jim W7EED

Don DeGregori
 

Hi Jim,

So all of the 4 windings are in series in a particular way as you describe. The schematic of the whole radio doesn't show it that way. I'll look at everything again. Thanks for you effort. I hope the next revision will consider your simplification.

Don ... W6RWN

Alan G4ZFQ
 

I hope the next revision will consider your simplification.
Don,

Somehow this discussion seems to be across 3 Subject lines. Is someone changing it?
https://groups.io/g/QRPLabs/topic/32802661#36777
https://groups.io/g/QRPLabs/topic/32818705#36805
https://groups.io/g/QRPLabs/topic/27485975#36819

But the essential fact is that the schematic can not reflect the physical layout. It would be virtually unreadable.

73 Alan G4ZFQ

Steve in Okinawa
 

Having the lead numbers printed on the circuit board will also be a big help.

terryhugheskirkcudbrifght@...
 

hi

did you have any difficulty in passing the wire for s1,2 and pri under the core

terry gm4dso

Joe Cotton
 

Hi Jim
Great hint for winding T1 for the QCX. The T1 winding step may be the hardest part of the whole megilla. 
The point that you make to wind the secondary winding 3 first and to mount the T1 as the first step are great ideas. 
However, your description of winding the primary and the secondary 1 and secondary 2 are not clear to me.  Allow me to say it in my own words and see if I understand you correctly. 

Step 1.  Wind secondary 3 over half of the toroid.  Solder it in holes 1 and 2, leaving room between the toroid and the board for wires (to come). 
Step 2.  Take about two inches of wire, tin one end, solder to hole 5.  This wire is standing straight up.
Step 3.  Bend the wire over the top of the toroid, then down into the toroid, and then underneath the toroid, coming out between hole 5 and hole 1. 
Step 4   Repeat step 3, two more times.
Step 5.  You should have a short length of wire left.  Bend this over the top of the toroid, and down into hole 6. Solder hole 6.

Step 6,  Repeat steps 2 through 5, for holes 3 and 4.  The first winding should come out between holes 3 and 5 in step 3.
Step 7.  Repeat steps 2 through 5, for holes 7 and 8.  The first winding should come out between holes 7 and 3 in step 3.

It's the step 3 which I want to get correct, and leave no doubt exactly what to do!  Do I have step 3 correct? I think that the windings all need to be in the correct direction. Do I have it correct?

thanks
Joe W3TTT

Joe Cotton
 

Looking over my previous post for the 20th time, I think that I need to add this.

Winding the secondary 3 over 180 degrees of the toroid,  Point a short lead down as you hold the toroid and the wire, wind the long end of the wire up, over the top, into the toroid, and under.  Continue in this direction. When finished winding, the short end that you started with will go in hole 1, and the long end will go in hole 2.    

The purpose of this instruction is to get the winding direction correct. 

It turns out (no pun intended) that all windings start out with a short end pointing down, held close to the toroid on the outside of the toroid.  Then the windings go up, over the top, inside the toroid, and underneath, coming back up on the outside of the toroid, on the right side of the previous turn, (with the turn facing you).  The turns will continue in a counter-clockwise direction, looking from the top. 

Joe W3TTT  

dkwflight
 

Hi
After my limited experience winding T1 I think I will try to color code the different sections along with your suggestion.
Thanks
Dennis
AG4TD

MrMSterner .
 

Good evening and thank's for letting me join the group extended with a lot of learning and joy.

I'm swedish in the middle age and just received my QCX CW 20m kit and following the group minutiously. However the T1 seems to be the "big challange".

I'm 43 yrs and when I was younger I completed my technician studies at highschool, after that I went over to IT (as many of you out there) and for today spent almost 19yrs at a Canadian company.

As a assembly constructor of the QCX20 I will start with the inventory and then assembly the  T1 first.

From my sight the suggested plan to follow the winding of S3 as a very good first step, solder it to the PCB and then continue the rest of windings of T1. I don't know who sent this picture but (frequency band dependent) allignment, left versus right hand in the 4 parts of winding, looks good. I also agree that the manual is a little bit un-clear in this part.

I hope to hear from you all soon in the future, perheps in a contest.

73
/s0Michael


On Sun, Aug 11, 2019, 22:13 dkwflight <dkwflight@...> wrote:
Hi
After my limited experience winding T1 I think I will try to color code the different sections along with your suggestion.
Thanks
Dennis
AG4TD

R. Tyson
 

Hi all,
Just take the time to study the diagrams and the photos. Make sure you have got it clear in your mind - go over the diagrams until you are happy that you know how it is done. It's not difficult and is nothing to be scared of. Once you have it mentally sorted Just make sure you have the correct number of turns on.

The most fiddly part is getting all the wire ends into the correct holes and pulling them down so the toroid fits snugly on the board. Make sure you get a good solder joint on each wire end - it will save you fault finding later on ! I clean each wire end before fitting the coil to the board as well as leaving the soldering iron on for several seconds.

The 40 meter coil was fairly easy to get into place. I found the 20 meter coil more difficult. There are only 3 turns on each secondary winding (if my memory is correct) and these kept loosening up and moving each time I tried to get all the wire ends in place through the board....  persistence and several attempts won out in the end.

Regard the whole thing as an exercise in patience !

Reg        G4NFR 

Ted 2E0THH
 

I strongly second these comments from Reg.
Like most, I had never wound a torroid in my life before the QCX40 and I just followed the instructions, 8000+ kits speaks for itself.

Over the years I have had a great deal of experience working with military specs and manuals for kit costing several magnitudes beyond $49! The QSX manual would put many of those to shame.

73s Ted
2E0THH


On Mon, Aug 12, 2019 at 10:32 AM, R. Tyson wrote:
Hi all,
Just take the time to study the diagrams and the photos. Make sure you have got it clear in your mind - go over the diagrams until you are happy that you know how it is done. It's not difficult and is nothing to be scared of. Once you have it mentally sorted Just make sure you have the correct number of turns on.

The most fiddly part is getting all the wire ends into the correct holes and pulling them down so the toroid fits snugly on the board. Make sure you get a good solder joint on each wire end - it will save you fault finding later on ! I clean each wire end before fitting the coil to the board as well as leaving the soldering iron on for several seconds.

The 40 meter coil was fairly easy to get into place. I found the 20 meter coil more difficult. There are only 3 turns on each secondary winding (if my memory is correct) and these kept loosening up and moving each time I tried to get all the wire ends in place through the board....  persistence and several attempts won out in the end.

Regard the whole thing as an exercise in patience !

Reg        G4NFR 

terryhugheskirkcudbrifght@...
 

hi all
i agree that it is best to start with mounting t1
i would add that it is best to mount all the toroids because you can then check for continuity ( and thus the solder joints)  if no other components are mounted.

terry gm4dso

terryhugheskirkcudbrifght@...
 

hi joe

step 4

how many times for 40 mtr

terry gm4dso

Chris Wood
 

Good morning

It has been said before, but it bears repeating:  cut the wire tails to different lengths, so that you aren't trying to poke them all through the pcb at the same time. 

Chris
G4CWS

On Monday, 12 August 2019, 11:11:04 BST, terryhugheskirkcudbrifght via Groups.Io <terryhugheskirkcudbrifght@...> wrote:


hi all
i agree that it is best to start with mounting t1
i would add that it is best to mount all the toroids because you can then check for continuity ( and thus the solder joints)  if no other components are mounted.

terry gm4dso

geoff M0ORE
 

Where did you get a copy of the QSX manual from?

On 12/08/2019 10:52, qrp@... wrote:
I strongly second these comments from Reg.
Like most, I had never wound a torroid in my life before the QCX40 and I just followed the instructions, 8000+ kits speaks for itself.

Over the years I have had a great deal of experience working with military specs and manuals for kit costing several magnitudes beyond $49! The QSX manual would put many of those to shame.

73s Ted
2E0THH


On Mon, Aug 12, 2019 at 10:32 AM, R. Tyson wrote:
Hi all,
Just take the time to study the diagrams and the photos. Make sure you have got it clear in your mind - go over the diagrams until you are happy that you know how it is done. It's not difficult and is nothing to be scared of. Once you have it mentally sorted Just make sure you have the correct number of turns on.

The most fiddly part is getting all the wire ends into the correct holes and pulling them down so the toroid fits snugly on the board. Make sure you get a good solder joint on each wire end - it will save you fault finding later on ! I clean each wire end before fitting the coil to the board as well as leaving the soldering iron on for several seconds.

The 40 meter coil was fairly easy to get into place. I found the 20 meter coil more difficult. There are only 3 turns on each secondary winding (if my memory is correct) and these kept loosening up and moving each time I tried to get all the wire ends in place through the board....  persistence and several attempts won out in the end.

Regard the whole thing as an exercise in patience !

Reg        G4NFR 

Ted 2E0THH
 

Hi Hi

But I'll bet it will be just as thorough!

73s Ted

2E0THH