Topics

T1 Winding/Soldering question

Jon Karve
 

Hi Everyone,

First I just wanted to say hello, I just recently got into amateur radio and have been very fascinated by all things HF and QRP.  I'm still learning CW, but I've successfully put together smaller/easier kits recently, made a decent (working) half wave end fed antenna, and and finally decided to try my hand at the 40m QCX kit. From the instructions for T1, I didn't have too much trouble winding it (other than snapping the wire 1/3 of the way through and barely having enough after unwinding and restarting), but after I mounted it to the board I'm second guessing the method I used.

The wires for holes 4, 6, and 8 come out from the bottom of the toroid, and I'm certain everything lines up correctly, but from the attached picture it looks like they are inserting the wire into hole 8 by passing the wire up, over, and through the center of the toroid, which I did (and did for all other "inside" holes), but now after having soldered and trimmed all of the connections I'm wondering if this was a mistake.  Did I just inadvertently add a 6th winding to 6, 4, and 8, or was this how it was intended? Was I supposed to squeeze the wire underneath the toroid to avoid this winding? If I did do this incorrectly, I'd rather know now before I get too much more on the board.

Thanks!!
Jon
KC3PDS

 

Jon,

First, welcome aboard!

The mantra for toroids is "every time the wire goes through the hole, that counts as one turn".

The holes in the circuit board are strtegically placed around either the inside or the outside edge of the toroid, so that for any winding the holes for the beginning and end are on the alternate concentric circle. If the hole isn't right where the wire is - or at least on the inside or outside ring as the wire goes down to the board,  you have probably not wound correctly.

I see that you're using the "modified way" of winding the coils, suggested for the 60m and 80m versions. When you cut the loop and fit the outer wire from each pair (i.e. the one coming UP through the middle and going DOWN the outside) you must push the end that comes out from under the outer edge back through to the inside and into the hole on the inner diameter of the toroid. Personally I don't find that method easier, and I suspect the manufacturer - Hans - didn't either, which is why it is only proposed for the 60 and 80m versions where there is so much wire that the coils overlap each other.

Worst of all though - and you're probably not going to like this - is that you appear to have wound 3 turns for the primary and S1, while the 40m version wants 5 turns :-(

Picture of my 40m T1 attached (I hope).


Julian N4JO.

On 6/11/2020 10:41 PM, kc3pds@... wrote:
Hi Everyone,

First I just wanted to say hello, I just recently got into amateur radio and have been very fascinated by all things HF and QRP.  I'm still learning CW, but I've successfully put together smaller/easier kits recently, made a decent (working) half wave end fed antenna, and and finally decided to try my hand at the 40m QCX kit. From the instructions for T1, I didn't have too much trouble winding it (other than snapping the wire 1/3 of the way through and barely having enough after unwinding and restarting), but after I mounted it to the board I'm second guessing the method I used.

The wires for holes 4, 6, and 8 come out from the bottom of the toroid, and I'm certain everything lines up correctly, but from the attached picture it looks like they are inserting the wire into hole 8 by passing the wire up, over, and through the center of the toroid, which I did (and did for all other "inside" holes), but now after having soldered and trimmed all of the connections I'm wondering if this was a mistake.  Did I just inadvertently add a 6th winding to 6, 4, and 8, or was this how it was intended? Was I supposed to squeeze the wire underneath the toroid to avoid this winding? If I did do this incorrectly, I'd rather know now before I get too much more on the board.

Thanks!!
Jon
KC3PDS

 

Unless, of course, I misunderstood you, and the attached picture isn't yours, but from the manual... ;-)

Use my pic as a reference, though, for how it should look - in terms of turns, anyway.

Julian N4JO.


On 6/11/2020 11:44 PM, Julian Opificius wrote:

Jon,

First, welcome aboard!

The mantra for toroids is "every time the wire goes through the hole, that counts as one turn".

The holes in the circuit board are strtegically placed around either the inside or the outside edge of the toroid, so that for any winding the holes for the beginning and end are on the alternate concentric circle. If the hole isn't right where the wire is - or at least on the inside or outside ring as the wire goes down to the board,  you have probably not wound correctly.

I see that you're using the "modified way" of winding the coils, suggested for the 60m and 80m versions. When you cut the loop and fit the outer wire from each pair (i.e. the one coming UP through the middle and going DOWN the outside) you must push the end that comes out from under the outer edge back through to the inside and into the hole on the inner diameter of the toroid. Personally I don't find that method easier, and I suspect the manufacturer - Hans - didn't either, which is why it is only proposed for the 60 and 80m versions where there is so much wire that the coils overlap each other.

Worst of all though - and you're probably not going to like this - is that you appear to have wound 3 turns for the primary and S1, while the 40m version wants 5 turns :-(

Picture of my 40m T1 attached (I hope).


Julian N4JO.

On 6/11/2020 10:41 PM, kc3pds@... wrote:
Hi Everyone,

First I just wanted to say hello, I just recently got into amateur radio and have been very fascinated by all things HF and QRP.  I'm still learning CW, but I've successfully put together smaller/easier kits recently, made a decent (working) half wave end fed antenna, and and finally decided to try my hand at the 40m QCX kit. From the instructions for T1, I didn't have too much trouble winding it (other than snapping the wire 1/3 of the way through and barely having enough after unwinding and restarting), but after I mounted it to the board I'm second guessing the method I used.

The wires for holes 4, 6, and 8 come out from the bottom of the toroid, and I'm certain everything lines up correctly, but from the attached picture it looks like they are inserting the wire into hole 8 by passing the wire up, over, and through the center of the toroid, which I did (and did for all other "inside" holes), but now after having soldered and trimmed all of the connections I'm wondering if this was a mistake.  Did I just inadvertently add a 6th winding to 6, 4, and 8, or was this how it was intended? Was I supposed to squeeze the wire underneath the toroid to avoid this winding? If I did do this incorrectly, I'd rather know now before I get too much more on the board.

Thanks!!
Jon
KC3PDS

Paul Harrison
 

Looks fine from here. 30 Sec/3 Prim. is correct for 20m.

Paul DJ0CU.


 

 It would be fine for a 20, Paul, but he's making a 40, as he says in his original post: "decided to try my hand at the 40m QCX kit. " :-)

Julian, N4JO.

On 6/12/2020 2:35 AM, Paul Harrison via groups.io wrote:
Looks fine from here. 30 Sec/3 Prim. is correct for 20m.

Paul DJ0CU.


Jon Karve
 

Yes this is the 40 meter version, sorry for the confusion here! The image I posted was just from the instructions, since I was more questioning my interpretation of it.  Here is a picture of my actual T1 on the board.

Jim Painter
 

Jon, welcome. This is not easy to explain but I’ll give it a try. If the core is wound properly, the leads should end up in the proper locations to match up with the holes in the board without manipulation.

If you lay the core flat, it makes a difference whether the first winding goes down through the core or up. You have to think about where the first and last turns will end up. If you have gone in the proper direction with the first turn, both ends will line up with the hole they should go into without making an extra wrap or crossing them over.

It is important that all wraps start the same way. That is to say, if the fast wrap goes up through the core, then all the following winds should start that way. I’m pretty sure the instructions mention that. It’s all about the phase relationship of the windings.

If all of your leads fell in line with the proper holes except the last one, then it may be that the last winding was done opposite from the others.

Hans, please correct me if I’m wrong.

Jim....KQ3S




On Jun 12, 2020, at 3:35 AM, Paul Harrison via groups.io <dj0cu@...> wrote:

Looks fine from here. 30 Sec/3 Prim. is correct for 20m.

Paul DJ0CU.


Jon Karve
 

Hi Jim/Julian/Paul,

Thanks for this explanation - I did follow the instruction manual for the winding, not winding each separately but making the 38 turns, twist a loop, 5 turns, twist, 5, twist 5.  Everything is definitely in the same direction, but I think the confusion was that in the instructions it looked like we are laying the toroid down and then untwisting/cutting the loops made, which would then have all of the wires on the oustide of the toroid.  

It sounds like from your explanation above, the windings that ended up on the under side should have stayed underneath the toroid, and should go through the inner holes immediately, so I likely have an extra wrap on the primary and secondary 1 and 2.  Not sure I'll be able to manipulate tiny tails that I have left to salvage it with the wire already wrapped, so I'll order some more and pull it off the board and re-wind.

Thank you everyone for the help!

 

Yes, it does look like you have 6, 6, 6 and 39 turns. That might still work, though...

And nice, tight, tidy wiring, b.t.w - congratulations !

One last thing: be very sure that you've burned off the insulation: one or two of hose connections on the inner circle don't look perfect - the little dip where the wire goes through is the give-away...

Julian, N4JO.

On 6/12/2020 8:10 AM, kc3pds@... wrote:
Yes this is the 40 meter version, sorry for the confusion here! The image I posted was just from the instructions, since I was more questioning my interpretation of it.  Here is a picture of my actual T1 on the board.

Jon Karve
 

Thanks, do you think it still would be usable as-is? I could just leave it and try, then redo it later on if there are major issues.

I did try to make sure the enamel was burned off, it looks cleaner on the underside.  I also did a quick DC continuity test with a multimeter with all 4 sets, which I believe is sufficient?

Simon Kennedy
 

One quick point based on my experience - if you are left handed (as I am) and you follow the instructions on winding T1 the ends to be soldered into the board end up in the wrong place. I fiddled with mind to get them into the correct holes but with no detrimental effect. YMMV.

73 Simon
G0FCU.

On Fri, 12 Jun 2020 at 15:13, <kc3pds@...> wrote:
Thanks, do you think it still would be usable as-is? I could just leave it and try, then redo it later on if there are major issues.

I did try to make sure the enamel was burned off, it looks cleaner on the underside.  I also did a quick DC continuity test with a multimeter with all 4 sets, which I believe is sufficient?

 

Somebody else should perhaps answer that question. It is sometimes necessary/helpful to remove a turn under certain conditions, but I've never heard of anybody having to add them, though I'm most certainly not an authority on that score.

Having said all that, I would have then said "well, if the connections are uncertain, it wouldn't hurt to pull the turn off and resolder anyway", but that is still easier said than done if you don't have good solder removal skills.

If it were me I would complete the assembly process with the minimum of disturbance, and get it ticking, then go and fix windings if you need to, In the meantime, you'll no doubt get more experienced advice on the winding count.

If you DO pull winding off, do this: 1. unsolder one wire from each coil; it doesn't matter electrically whether it's form the inside circle or the outside circle. DON'T cut the wires shorter yet. 2. Clean the holes properly using desoldering braid or a vacuum. 3. estimate where the feed-through point would be on each of the free wires, and clean the varnish off at that point. Don't worry about the ends. 4. Feed the cleaned wires through and solder carefully. THEN snip off the ends.

Julian, N4JO.

On 6/12/2020 9:13 AM, kc3pds@... wrote:
Thanks, do you think it still would be usable as-is? I could just leave it and try, then redo it later on if there are major issues.

I did try to make sure the enamel was burned off, it looks cleaner on the underside.  I also did a quick DC continuity test with a multimeter with all 4 sets, which I believe is sufficient?

Jon Karve
 

Simon - I never thought of left/right handedness being a factor there, but I think I was winding just a tiny bit off of what the board was expecting, so I did have to fiddle a tiny bit to get everything lining up.  My windings were counter-clockwise starting with the 38, then the sets of 5 (which are now all increased by 1).

Julian - Thanks, I didn't think of the fact that I could leave the "difficult" wires (inside) alone and just desolder the corresponding outside ones to remove a turn.  I'll re-examine this afternoon and will likely do this before continuing.  I'd say my soldering skills are "intermediate", I haven't done a ton of desoldering though.  I have worked with hobby electronics/microcontrollers for a number of years and have played around with etching my own PCBs, all SMD and making things work with typically through hole components, but still fun and everything has worked so far.

I do have both a desoldering braid and a vaccum - I'll give both methods a shot on a spare proto board that I have and see which one I'm the most comfortable with.  If possible I'd like to just fix this now and not have this potential issue looming over my head while I continue on with the build.

Thanks again!

Jon, KC3PDS

 

Jon,

Yes, considering your obviously more-than-adequate skill level, I think that's a wise choice.

I know that over the various releases of the QCX Hans has moved the construction and installation of T1 from the end of the construction - by which point it was considered that a new constructor would have brushed up his or her skills - to the beginning, where there is the maximum access and minimum likelihood of damaging any other components in the installation process.

Like the other manuals for QRP-Labs products, this manual is written extremely well, and has been the subject of many well-deserved complimentary comments. It absolutely deserves to be read well at all points during construction and calibration processes, and for operational guidance. I myself would separate the third section from the first two, but no matter. I have seen on several occasions even experienced constructors lament that they didn't RTFM first :-)  Take note of this if you choose to purchase a PA for your QCX later on!

Good luck :-)

Julian N4JO.

On 6/12/2020 9:37 AM, kc3pds@... wrote:
Simon - I never thought of left/right handedness being a factor there, but I think I was winding just a tiny bit off of what the board was expecting, so I did have to fiddle a tiny bit to get everything lining up.  My windings were counter-clockwise starting with the 38, then the sets of 5 (which are now all increased by 1).

Julian - Thanks, I didn't think of the fact that I could leave the "difficult" wires (inside) alone and just desolder the corresponding outside ones to remove a turn.  I'll re-examine this afternoon and will likely do this before continuing.  I'd say my soldering skills are "intermediate", I haven't done a ton of desoldering though.  I have worked with hobby electronics/microcontrollers for a number of years and have played around with etching my own PCBs, all SMD and making things work with typically through hole components, but still fun and everything has worked so far.

I do have both a desoldering braid and a vaccum - I'll give both methods a shot on a spare proto board that I have and see which one I'm the most comfortable with.  If possible I'd like to just fix this now and not have this potential issue looming over my head while I continue on with the build.

Thanks again!

Jon, KC3PDS

Jon Karve
 

Julian,

Thanks again for all of this - I just examined this again, and I clearly had 6 turns on each that were supposed to be 5.  I followed your advise and removed the "outside" leads, cleaned the holes, removed a turn, tinned and soldered - everything was successful, with one caveat.  I also successfully lifted one of the pads off of the board, probably with too much heat from the iron when desoldering.  The lead is still intact and I verified it a DMM, so I'm going to cover it with a little hot glue and hope for the best :)

Other than that I'm fairly certain this is finally on correctly.  I appreciate all of the help from everyone and am very excited to get this up and running! The rest of the build should be cake compared to this :)

Jon KC3PDS

 

Yeah, that was my concern. Never mind, looks like you fixed it.

Yes, it gets easier from here - just more monotonous:-)

I do recommend you follow the guidance on the orientation of the resistor leads - it's not arbitrary. In addition to spacing, for the most part the orientation of the folded over downlead helps with signal searching if things go wrong.

Last thing: do make sure you set the multi-turn trimmers to midpoint (or at least not at the end) before you start to calibrate.

Julian, N4JO.

On 6/12/2020 11:30 AM, kc3pds@... wrote:
Julian,

Thanks again for all of this - I just examined this again, and I clearly had 6 turns on each that were supposed to be 5.  I followed your advise and removed the "outside" leads, cleaned the holes, removed a turn, tinned and soldered - everything was successful, with one caveat.  I also successfully lifted one of the pads off of the board, probably with too much heat from the iron when desoldering.  The lead is still intact and I verified it a DMM, so I'm going to cover it with a little hot glue and hope for the best :)

Other than that I'm fairly certain this is finally on correctly.  I appreciate all of the help from everyone and am very excited to get this up and running! The rest of the build should be cake compared to this :)

Jon KC3PDS

Jon Karve
 

Yeah I'm much more confident in it now that this is squared away.  For the resistor leads comment, are you referring to the O- on the board, ensuring the resistor is vertically place in the circle? I've recently built a pixie and a Forty-9er clone that both had the vertical orientation, but let me know if this is something different.  I did see a special note in the instructions about this.

I'll definitely ensure the trimmers are in the midpoint as well, that sounds like common sense but also something easy to miss.

Thanks again!
Jon KC3PDS

 

Jon,

Yes, the "O" on the silk screen, that's exactly what I mean. I only mention it  because to some folk it's obvious, some folk are oblivious :-)

One of the trimmers - can't remember which one - if one-ended will prevent even a basic coarse adjustment. Easier just to mid-point them to start.

Julian, N4JO.

On 6/12/2020 11:53 AM, kc3pds@... wrote:
Yeah I'm much more confident in it now that this is squared away.  For the resistor leads comment, are you referring to the O- on the board, ensuring the resistor is vertically place in the circle? I've recently built a pixie and a Forty-9er clone that both had the vertical orientation, but let me know if this is something different.  I did see a special note in the instructions about this.

I'll definitely ensure the trimmers are in the midpoint as well, that sounds like common sense but also something easy to miss.

Thanks again!
Jon KC3PDS

Jon Karve
 

Julian,

Thanks for that, it looks like this board is pretty tight, it probably wouldn't have made a difference on the previous builds if the resistors were in the opposite hole, but might make things trickier here.  I'll make sure everything is in as designed, hopefully should be able to complete the rest of this over the weekend.

Thanks again for all of the help, I'll definitely be reaching out again if I run into anything else.

Jon, KC3PDS

 

You're welcome, Jon, and please do.

Julna, N4JO.

On 6/12/2020 3:01 PM, Jon Karve wrote:
Julian,

Thanks for that, it looks like this board is pretty tight, it probably wouldn't have made a difference on the previous builds if the resistors were in the opposite hole, but might make things trickier here.  I'll make sure everything is in as designed, hopefully should be able to complete the rest of this over the weekend.

Thanks again for all of the help, I'll definitely be reaching out again if I run into anything else.

Jon, KC3PDS