Topics

80 meter cw rig #80m

Don Blachura
 

Built a 20 meter and 40 meter rig and all great.
Finished a 80 meter cw rig and is fine until I transmit.
Getting smoke around the coils.Have it rx fb. Checked for solder bridges etc.
Short in one of the torrid winding? Gets hot under the coils.

Don..w2xb

N3MNT
 

Assume you are referring to LPF coils. Can you post closeup photo of that area of the board.  Are you sure all items installed in correct position?

Don Blachura <w2xbwa2hpw@...>
 

Yes the LPF torrids. Inclosed is a pix , but not very good. Camera stinks.

 

Don..w2xb

 

Learning to send a pix with i-pad..not to yet. At 82 getting there.

 

Sent from Mail for Windows 10

 

From: N3MNT
Sent: Wednesday, March 11, 2020 8:46 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] 80 meter cw rig #80m

 

Assume you are referring to LPF coils. Can you post closeup photo of that area of the board.  Are you sure all items installed in correct position?

 

George Korper
 

Are there any updates for this topic? I am very interested in 80 meters. 
Anyone who has built an 80 meter QCX, would love to hear about it and get some guidance. 

Richard Hall
 

I finished my 80 meter QCX last week without a problem. I used the alternate technique for T1: wind the big secondary in a single layer all the way around and then the other windings on top. I also wound 71 turns as I figured it would be easier to remove turns than to add. I ended up with 69 turns.
80 is noisy. You should be prepared for that. I am having good luck with a receiving antenna: https://www.qsl.net/kc2tx/loopschematic.htm and pre-amp: http://www.mtmscientific.com/preamp.html
I have ordered the 50W PA and will build it for 80. Barefoot, I have reached Mexico and Oregon from Burbank, CA.
Richard
NS3C

George Korper
 

TNX. I will follow your instructions.


On Wed, Apr 1, 2020, 12:44 PM Richard Hall <n76003@...> wrote:
I finished my 80 meter QCX last week without a problem. I used the alternate technique for T1: wind the big secondary in a single layer all the way around and then the other windings on top. I also wound 71 turns as I figured it would be easier to remove turns than to add. I ended up with 69 turns.
80 is noisy. You should be prepared for that. I am having good luck with a receiving antenna: https://www.qsl.net/kc2tx/loopschematic.htm and pre-amp: http://www.mtmscientific.com/preamp.html
I have ordered the 50W PA and will build it for 80. Barefoot, I have reached Mexico and Oregon from Burbank, CA.
Richard
NS3C

Christiaan PA3FUN
 

Hi George. I'm using QCX on 80 for about half a year now. And yes - it works GREAT.
I encountered nothing unusual when building the kit. Besides the winding of T1, on which topic light has been shed by many, it's "business as usual". About two months ago I also build the 50W amp for 80m and noticed "it goes along well" 😊.
The caps needed for 80m (LPF) were obtained the easy way; I bought two Amp-kits. Since each kit is supplied with all caps necessary for building it for 40/30/15, I simply borrowed some caps from kit#1 to complete kit#2 for 80m, still being able to complete kit#1 for 40m using the remaining caps 🙂👍.
Should you need any help fixing your 80m QSX please let me know. WhatsApp video-call may be the easiest way.
73's Chrostiaan PA3FUN

George Korper
 

Hello Christiaan,
This is welcome news. Since it is very early here, and I have two amp kits, let me see if I understand. Which capacitors 
are used for the 80 meter amp, and what are the correct windings for the three inductors? I'm sure I could eventually figure that out,
but I'd rather follow in you successful footsteps! Thanks for the help. 
All Best 73,
George
K3GK

On Thu, Apr 16, 2020 at 4:16 AM Christiaan PA3FUN <christiaan@...> wrote:
Hi George. I'm using QCX on 80 for about half a year now. And yes - it works GREAT.
I encountered nothing unusual when building the kit. Besides the winding of T1, on which topic light has been shed by many, it's "business as usual". About two months ago I also build the 50W amp for 80m and noticed "it goes along well" 😊.
The caps needed for 80m (LPF) were obtained the easy way; I bought two Amp-kits. Since each kit is supplied with all caps necessary for building it for 40/30/15, I simply borrowed some caps from kit#1 to complete kit#2 for 80m, still being able to complete kit#1 for 40m using the remaining caps 🙂👍.
Should you need any help fixing your 80m QSX please let me know. WhatsApp video-call may be the easiest way.
73's Chrostiaan PA3FUN

Hans Summers
 

Hi all

Note, in my opinion:

1) There are 4 pairs of capacitors in the 50W PA kit; these are intended to be able to build it for 40, 30 or 20m. However, if you pair up those capacitors in the right way you will be able to get quite close to the "usual" values 470pF and 1200pF. So:
180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

2) Normally we use -2 material for 80m LPFs but I believe calculating the right number of turns and winding them on the supplied (yellow) T50-6 toroids should work fine. There may or may not be sufficient wire in the kit for this, but wire diameter is not critical so you may substitute something. 

In this case - the kit should be buildable as supplied, for 80m band. I have not yet had time to try it myself. When I do, and obtain the comparable measurements, then I could update the assembly manual to include 80m. 

73 Hans G0UPL

On Thu, Apr 16, 2020 at 12:34 PM George Korper <georgekorper@...> wrote:
Hello Christiaan,
This is welcome news. Since it is very early here, and I have two amp kits, let me see if I understand. Which capacitors 
are used for the 80 meter amp, and what are the correct windings for the three inductors? I'm sure I could eventually figure that out,
but I'd rather follow in you successful footsteps! Thanks for the help. 
All Best 73,
George
K3GK

On Thu, Apr 16, 2020 at 4:16 AM Christiaan PA3FUN <christiaan@...> wrote:
Hi George. I'm using QCX on 80 for about half a year now. And yes - it works GREAT.
I encountered nothing unusual when building the kit. Besides the winding of T1, on which topic light has been shed by many, it's "business as usual". About two months ago I also build the 50W amp for 80m and noticed "it goes along well" 😊.
The caps needed for 80m (LPF) were obtained the easy way; I bought two Amp-kits. Since each kit is supplied with all caps necessary for building it for 40/30/15, I simply borrowed some caps from kit#1 to complete kit#2 for 80m, still being able to complete kit#1 for 40m using the remaining caps 🙂👍.
Should you need any help fixing your 80m QSX please let me know. WhatsApp video-call may be the easiest way.
73's Chrostiaan PA3FUN

George Korper
 

Ok Hans, Thank you. 80 will be there when you ready. 


On Thu, Apr 16, 2020 at 5:38 AM Hans Summers <hans.summers@...> wrote:
Hi all

Note, in my opinion:

1) There are 4 pairs of capacitors in the 50W PA kit; these are intended to be able to build it for 40, 30 or 20m. However, if you pair up those capacitors in the right way you will be able to get quite close to the "usual" values 470pF and 1200pF. So:
180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

2) Normally we use -2 material for 80m LPFs but I believe calculating the right number of turns and winding them on the supplied (yellow) T50-6 toroids should work fine. There may or may not be sufficient wire in the kit for this, but wire diameter is not critical so you may substitute something. 

In this case - the kit should be buildable as supplied, for 80m band. I have not yet had time to try it myself. When I do, and obtain the comparable measurements, then I could update the assembly manual to include 80m. 

73 Hans G0UPL

On Thu, Apr 16, 2020 at 12:34 PM George Korper <georgekorper@...> wrote:
Hello Christiaan,
This is welcome news. Since it is very early here, and I have two amp kits, let me see if I understand. Which capacitors 
are used for the 80 meter amp, and what are the correct windings for the three inductors? I'm sure I could eventually figure that out,
but I'd rather follow in you successful footsteps! Thanks for the help. 
All Best 73,
George
K3GK

On Thu, Apr 16, 2020 at 4:16 AM Christiaan PA3FUN <christiaan@...> wrote:
Hi George. I'm using QCX on 80 for about half a year now. And yes - it works GREAT.
I encountered nothing unusual when building the kit. Besides the winding of T1, on which topic light has been shed by many, it's "business as usual". About two months ago I also build the 50W amp for 80m and noticed "it goes along well" 😊.
The caps needed for 80m (LPF) were obtained the easy way; I bought two Amp-kits. Since each kit is supplied with all caps necessary for building it for 40/30/15, I simply borrowed some caps from kit#1 to complete kit#2 for 80m, still being able to complete kit#1 for 40m using the remaining caps 🙂👍.
Should you need any help fixing your 80m QSX please let me know. WhatsApp video-call may be the easiest way.
73's Chrostiaan PA3FUN

Christiaan PA3FUN
 

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

Hans Summers
 

Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

George Korper
 

Things come to those who wait.


On Thu, Apr 16, 2020, 1:12 PM Hans Summers <hans.summers@...> wrote:
Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

Dave
 

I use the half inch cores for QRP and want to use one inch cores at 100W level. Too much power in a core will saturate the core, causing loss of inductance.  The core might even be damaged physically, shattering from the heat.  Then damage ensues to the PA.  I would rather not go there.

Quick question Hans:  I want to order some RF caps for other projects, and the choices at DigiKey are daunting.  What series are you supplying with the LPF and BPF?  Please!

Dave


On Apr 16, 2020, at 14:12, Hans Summers <hans.summers@...> wrote:


Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

Hans Summers
 

Hi Dave

Most are 50V 0.1-inch spaced, radial ceramic C0G/NP0 e.g. part number BC5151-ND for 470pF. 

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

On Thu, Apr 16, 2020 at 10:20 PM Dave <VE3GSO@...> wrote:
I use the half inch cores for QRP and want to use one inch cores at 100W level. Too much power in a core will saturate the core, causing loss of inductance.  The core might even be damaged physically, shattering from the heat.  Then damage ensues to the PA.  I would rather not go there.

Quick question Hans:  I want to order some RF caps for other projects, and the choices at DigiKey are daunting.  What series are you supplying with the LPF and BPF?  Please!

Dave


On Apr 16, 2020, at 14:12, Hans Summers <hans.summers@...> wrote:


Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

Christiaan PA3FUN
 

Hi Hans.
You're absolutely right. But there's some miscommunication I now realize.
I used T37-2 in the QCX LPF for 80m. I used T50-2 in the Amp's LPF.
Sorry for not being clear on that in my previous post.
73s Christiaan PA3FUN

Dave
 

Thank you!  That helps a lot.

I credit all the QRP-Labs kits I’ve been building with helping avoid cabin fever during this lockdown!

Dave

Dave


On Apr 16, 2020, at 16:23, Hans Summers <hans.summers@...> wrote:


Hi Dave

Most are 50V 0.1-inch spaced, radial ceramic C0G/NP0 e.g. part number BC5151-ND for 470pF. 

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

On Thu, Apr 16, 2020 at 10:20 PM Dave <VE3GSO@...> wrote:
I use the half inch cores for QRP and want to use one inch cores at 100W level. Too much power in a core will saturate the core, causing loss of inductance.  The core might even be damaged physically, shattering from the heat.  Then damage ensues to the PA.  I would rather not go there.

Quick question Hans:  I want to order some RF caps for other projects, and the choices at DigiKey are daunting.  What series are you supplying with the LPF and BPF?  Please!

Dave


On Apr 16, 2020, at 14:12, Hans Summers <hans.summers@...> wrote:


Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN

geoff M0ORE
 

For capacitors and other radio components, try "Just radios" at www.justradios.com.  I purchased some 500 volt, 1% silver micas for a  LPF board last year and had very good service. Located in Ontario Canada and are delivering by post during the current lockdown.

Geoff

On 16/04/2020 20:20, Dave wrote:
I use the half inch cores for QRP and want to use one inch cores at 100W level. Too much power in a core will saturate the core, causing loss of inductance.  The core might even be damaged physically, shattering from the heat.  Then damage ensues to the PA.  I would rather not go there.

Quick question Hans:  I want to order some RF caps for other projects, and the choices at DigiKey are daunting.  What series are you supplying with the LPF and BPF?  Please!

Dave


On Apr 16, 2020, at 14:12, Hans Summers <hans.summers@...> wrote:


Christian, all

I'm not convinced T37 size is healthy for 50W... any opinions on this? After all, that's why I put T50 size toroids in the 50W Amp kit...

73 Hans G0UPL 

On Thu, Apr 16, 2020, 20:37 Christiaan PA3FUN <christiaan@...> wrote:

Hi George, Hans e.a.

I wound the three LPF-toroids onto three little red T37-2 core's lying around in my shack. And simply used the inductances as defined in the QRP_labs LPF-filter as decribed on this page: https://qrp-labs.com/lpfkit

L1/L3: 25 (2.42uH)
L2: 27 (3.01uH)

Before assembly I verified & tuned the inductances to the above values using an inductance-meter. Worked like a charm the very first time :).

Regarding combining caps: I did just that what Hans suggests:

180 + 270 = 450pF (close to 470oF)
390 + 680pF = 1070pF (close-ish to 1200pF)

Good luck! Christiaan PA3FUN