Topics

Winding QCX T1 #t1 #qcx

Richard G4TGJ
 

In the photo of T1 in the QCX manual it shows the 4 windings as very distinctively separate. The 30 turn winding takes up half the toroid and then there are 3x3 turn windings, each being quite tight with a large gap to the next one. In my 30m version all the turns are spread around the toroid fairly evenly. Does this matter? I am failing to get a minimum with the Phase Low and Phase High adjustments and am getting to the end stop.

Martin
 

I can't tell, what I did wrong but facing the same problem I took T 1 out again took all the windings off and did it again. It looked much neater then and it worked fine.

Fot the lack of output I took of turns from the toroids in the filter and replaced the 390 pf by something of better quality. Its not perfect but I get 4 W at 15 V.

Martin
DK3UW

Alan G4ZFQ
 

In the photo of T1 in the QCX manual it shows the 4 windings as very distinctively separate. The 30 turn winding takes up half the toroid and then there are 3x3 turn windings, each being quite tight with a large gap to the next one. In my 30m version all the turns are spread around the toroid fairly evenly. Does this matter?
Richard,

With these types of coils it does not actually make much difference.
>I am failing to get a
minimum with the Phase Low and Phase High adjustments and am getting to the end stop.
But as Martin says T1 and it's soldering is the first thing to look at.

73 Alan G4ZFQ

Richard G4TGJ
 

I've created a spreadsheet calculating the phase shift through IC6 and IC7. This shows that the correct 90 degree phase difference should happen when R17 and R24 are at their midpoints. So I think I will start by checking that these are soldered correctly. Across R14 and R21 I should measure about 8.3K and 6.5K so this seems a good place to start.

Martin
 

are you sure of T1. All coils in the same sense, connected correctly and perfectly welded ? That would be (was) my starting point.

Martin

Richard G4TGJ
 

I will check that too.

Richard G4TGJ
 

I took voltage measurements and got a very strange result on T1. 4 connections should be at 0V and 4 at 2.5V, but 1 was at 3.5V! So clearly the enamel hadn't burnt off despite my best efforts. I put the soldering on the joint for another 10 seconds and after that the voltages are now correct. However I still cannot get the phase low and high alignment to work. Very frustrating.

Alan G4ZFQ
 

on T1. 4 connections should be at 0V and 4 at 2.5V, but 1 was at 3.5V! So clearly the enamel hadn't burnt off despite my best efforts. I put the soldering on the joint for another 10 seconds and after that the voltages are now correct. However I still cannot get the phase low and high alignment to work.
Richard,

Are you sure there is not another bad connection? I'm not sure if voltage readings are reliable for checking all connections. And are you sure the windings are in the same direction? Otherwise check soldering along the path and check IC voltages.

73 Alan G4ZFQ

Richard G4TGJ
 

I'm not sure! In fact I'm sure there must be something wrong otherwise it would be working.

I've taken some readings again, this time with the internal volt meter. All the ICs look fine - some of the readings taken with my DVM were much higher than in the manual but that's because of the low impedance of the internal meter.

One thing I have noticed with the voltages on T1 are that pins 5 and 6 are different by 0.02V (1.77V and 1.79V with the internal meter and 2.54V and 2.56V with the DVM). Since these coils are just a few turns I assume they should be the same voltage. That enamel seems to be very tough!

Kurt Zimmerman
 

When it comes to T1 I made an effort to start by sanding the varnish off the leads.  Then I heated each lead to burn off anything I might have missed.  So far I'm 2 for 2 with positive results.  I plan on doing that with my 30m version as well.

The piece of sandpaper I use is smaller than a postage stamp.  It is just large enough where I can fold it over then pass the wire through it.  I do this several times until I see the copper lead becomes dull in appearance.  At this point I'm quite confident that most if not all of the varnish has been removed.  The heating the lead makes it about 100%

Good luck.
73;
Kurt - W2MW

-------- Original Message --------
Subject: Re: [QRPLabs] Winding QCX T1 #qcx #t1
From: "Richard G4TGJ" <rpt@...>
Date: Wed, July 25, 2018 8:28 am
To: QRPLabs@groups.io

I'm not sure! In fact I'm sure there must be something wrong otherwise it would be working.

I've taken some readings again, this time with the internal volt meter. All the ICs look fine - some of the readings taken with my DVM were much higher than in the manual but that's because of the low impedance of the internal meter.

One thing I have noticed with the voltages on T1 are that pins 5 and 6 are different by 0.02V (1.77V and 1.79V with the internal meter and 2.54V and 2.56V with the DVM). Since these coils are just a few turns I assume they should be the same voltage. That enamel seems to be very tough!

Steve in Okinawa
 

I built a Weber Tribander a few years ago (old-school "SA612A Sandwich") and the anxiety with toroid winding was completely absent because the wire supplied had insulation that burned cleanly off with a touch of molten solder. No doubt Hans has a lifetime supply of the currently supplied magnet wire, but individual QCX builders could substitute for it. Sorry, I can't recall the trade name for that type of insulation

Steve Fabricant JS6TMW 

On Jul 25, 2018, at 23:14, Kurt Zimmerman <kurt@...> wrote:

When it comes to T1 I made an effort to start by sanding the varnish off the leads.  Then I heated each lead to burn off anything I might have missed.  So far I'm 2 for 2 with positive results.  I plan on doing that with my 30m version as well.

The piece of sandpaper I use is smaller than a postage stamp.  It is just large enough where I can fold it over then pass the wire through it.  I do this several times until I see the copper lead becomes dull in appearance.  At this point I'm quite confident that most if not all of the varnish has been removed.  The heating the lead makes it about 100%

Good luck.
73;
Kurt - W2MW
-------- Original Message --------
Subject: Re: [QRPLabs] Winding QCX T1 #qcx #t1
From: "Richard G4TGJ" <rpt@...>
Date: Wed, July 25, 2018 8:28 am
To: QRPLabs@groups.io

I'm not sure! In fact I'm sure there must be something wrong otherwise it would be working.

I've taken some readings again, this time with the internal volt meter. All the ICs look fine - some of the readings taken with my DVM were much higher than in the manual but that's because of the low impedance of the internal meter.

One thing I have noticed with the voltages on T1 are that pins 5 and 6 are different by 0.02V (1.77V and 1.79V with the internal meter and 2.54V and 2.56V with the DVM). Since these coils are just a few turns I assume they should be the same voltage. That enamel seems to be very tough!

Old Dog
 

That enamel can be tough but I've never seen any insulation or enamel that could survive anealing the end of wire in the flame of a lighter.  That and a little flux and job done!

On Wed, Jul 25, 2018 at 10:14 AM, Kurt Zimmerman <kurt@...> wrote:
When it comes to T1 I made an effort to start by sanding the varnish off the leads.  Then I heated each lead to burn off anything I might have missed.  So far I'm 2 for 2 with positive results.  I plan on doing that with my 30m version as well.

The piece of sandpaper I use is smaller than a postage stamp.  It is just large enough where I can fold it over then pass the wire through it.  I do this several times until I see the copper lead becomes dull in appearance.  At this point I'm quite confident that most if not all of the varnish has been removed.  The heating the lead makes it about 100%

Good luck.
73;
Kurt - W2MW
-------- Original Message --------
Subject: Re: [QRPLabs] Winding QCX T1 #qcx #t1
From: "Richard G4TGJ" <rpt@...>
Date: Wed, July 25, 2018 8:28 am
To: QRPLabs@groups.io

I'm not sure! In fact I'm sure there must be something wrong otherwise it would be working.

I've taken some readings again, this time with the internal volt meter. All the ICs look fine - some of the readings taken with my DVM were much higher than in the manual but that's because of the low impedance of the internal meter.

One thing I have noticed with the voltages on T1 are that pins 5 and 6 are different by 0.02V (1.77V and 1.79V with the internal meter and 2.54V and 2.56V with the DVM). Since these coils are just a few turns I assume they should be the same voltage. That enamel seems to be very tough!




David Wilcox
 

Also, clean the wire RIGHT UP TO THE BASE OF THE TOROID! Many times I thought I had cleaned it far enough but when I pulled it through with a little tension it went a little bit farther than I had sanded and a poor connection was the result. Oh the head ache. Even aspirin didn't help!

Dave K8WPE

On Jul 25, 2018, at 10:14 AM, Kurt Zimmerman <kurt@...> wrote:

When it comes to T1 I made an effort to start by sanding the varnish off the leads.  Then I heated each lead to burn off anything I might have missed.  So far I'm 2 for 2 with positive results.  I plan on doing that with my 30m version as well.

The piece of sandpaper I use is smaller than a postage stamp.  It is just large enough where I can fold it over then pass the wire through it.  I do this several times until I see the copper lead becomes dull in appearance.  At this point I'm quite confident that most if not all of the varnish has been removed.  The heating the lead makes it about 100%

Good luck.
73;
Kurt - W2MW
-------- Original Message --------
Subject: Re: [QRPLabs] Winding QCX T1 #qcx #t1
From: "Richard G4TGJ" <rpt@...>
Date: Wed, July 25, 2018 8:28 am
To: QRPLabs@groups.io

I'm not sure! In fact I'm sure there must be something wrong otherwise it would be working.

I've taken some readings again, this time with the internal volt meter. All the ICs look fine - some of the readings taken with my DVM were much higher than in the manual but that's because of the low impedance of the internal meter.

One thing I have noticed with the voltages on T1 are that pins 5 and 6 are different by 0.02V (1.77V and 1.79V with the internal meter and 2.54V and 2.56V with the DVM). Since these coils are just a few turns I assume they should be the same voltage. That enamel seems to be very tough!

BC
 

I have yet to build a QCX, but when I want to remove the varnish from wire, I scrape most of it off with a sharp knife.

Bob
AG7OZ

Richard G4TGJ
 

So I redid a number of solder joints on T1 but it still didn't want to align. Then I plugged a dummy load in and found that I could get it to align properly. I note that the instructions on p67 say to unplug the antenna during alignment of the radio but don't say to plug in a dummy load.

Al Holt
 

On Thu, Aug 2, 2018 at 11:20 AM, Richard G4TGJ wrote:
I note that the instructions on p67 say to unplug the antenna during alignment of the radio but don't say to plug in a dummy load.
I believe I read here on this group Hans mentioning connection to a dummy load can help alignment. I think the original instructions emphasize disconnecting the antenna because the alignment signal is injected just about at the antenna connection and having an antenna attached would radiate a possible interference. I recall my QCX-40 would align both with and without the dummy load attached.

--Al

 

Hi Al, is there a difference??

Juan Herrera HK6J 
Enviado desde mi iPhone

El 2/08/2018, a la(s) 10:44 a. m., Al Holt <grovekid2@...> escribió:

On Thu, Aug 2, 2018 at 11:20 AM, Richard G4TGJ wrote:
I note that the instructions on p67 say to unplug the antenna during alignment of the radio but don't say to plug in a dummy load.
I believe I read here on this group Hans mentioning connection to a dummy load can help alignment. I think the original instructions emphasize disconnecting the antenna because the alignment signal is injected just about at the antenna connection and having an antenna attached would radiate a possible interference. I recall my QCX-40 would align both with and without the dummy load attached.

--Al

Alan de G1FXB
 


I suspect Han's has being sidetracked to have rewritten that section into the build manuals so far.
Please read the whole thread for background but:-

Specifically message  https://groups.io/g/QRPLabs/message/22418


Alan

On 02/08/2018 16:51, Juano wrote:
Hi Al, is there a difference??

Juan Herrera HK6J 
Enviado desde mi iPhone

El 2/08/2018, a la(s) 10:44 a. m., Al Holt <grovekid2@...> escribió:

On Thu, Aug 2, 2018 at 11:20 AM, Richard G4TGJ wrote:
I note that the instructions on p67 say to unplug the antenna during alignment of the radio but don't say to plug in a dummy load.
I believe I read here on this group Hans mentioning connection to a dummy load can help alignment. I think the original instructions emphasize disconnecting the antenna because the alignment signal is injected just about at the antenna connection and having an antenna attached would radiate a possible interference. I recall my QCX-40 would align both with and without the dummy load attached.

--Al

N3MNT
 

If the enamel is not cleaned off the leads of T1 you will have very low readings when trying to maximize  readings and very unstable readings when trying to minimize the others.  Simply reheat each T1 solder connection for about 10sec each and your issue should be resolved.  If uncertain, use an ohm meter to measure resistance between the ends of the windings be sure to measure on the pad and not the end of the wire.

n3fel@aol.com
 

I just completed my QCX40 and simpathize with others who were/are challenged by The T1. In my case I had to unwind one turn of the large coil and strip back the end insulation.  I must have nicked the wire trying to scrap it clean with a sharp exacto blade and when pulling it through one of the eight holes it broke off at the base of the coil.  Recommendation:  Don't scrape!  Use the flame sparingly from a butane lighter to burn off the insulation.  Then allow 10s heat time to solder the connection.  Hope this helps.  Howard, n3fel