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QMX+ Toasted L-518 Toroid -- Cause ?

 

My QMX+, built for 12V version, has been performing well for some weeks.? I decided to tweak the LPF toroids to see if IO could boost power a bit.
Imagine my surprise when L-518, one of two toroids for 10 and 12 meters, felt like mush when I squeezed it.
Further exam revealed it had split in four places, as can be seen in the attached photo.
I'm asking for advice on what caused the damage, so I can avoid that behavior in the future. I'm presuming one of my 12V batteries was over-charged to 13.8v, or maybe an SWR adjustment using either a T-1 or a ZM-2 'searched' into a damaging SWR range.
Since the radio still seems to function as normal, should I bother to replace L-518?? Rather than risk hole or pad damage, I'd snip this one out, and install a new one wire-to-wire.
I'd appreciate your thoughts/advice.
- Bill? W3WJ
?
?
 

Hi Bill,

I doubt, that electrical issues/heat caused such a defect.
The wire will become black first. Then the colour of the core mantle will change. It won't break that fast.
It only could have been mechanical stress or a production fault.
?
73 Peter
 

Your toroids must be wound really tight! - lol. I think you can use cyanoacrylate glue (ie Crazy Glue) to glue it back together with negligible effect on it's RF properties. Just don't glue it to your finger like I did...

72 de va3rr
 

Hi Bill

Always remember: "if it ain't broke, don't fix it!". Ok I know yours actually IS broken but still the radio works fine... So leave it be. Note that the -0 material is permeability zero. It's the same as winding on air. It doesnt even have any magnetic properties to restore by glueing it back together, which would otherwise be the advice on a toroid with actual permeability. The only reason for having the toroid there at all is that you can't easily and repeatably and reliably wind such a nice toroid on air. It just provides a nice convenient shape so that when I say 25 turns it always comes out at approximately similar inductance every time..

73 Hans G0UPL


On Sun, Aug 11, 2024, 20:55 Bill Jobes via <jobes=[email protected]> wrote:
My QMX+, built for 12V version, has been performing well for some weeks.? I decided to tweak the LPF toroids to see if IO could boost power a bit.
Imagine my surprise when L-518, one of two toroids for 10 and 12 meters, felt like mush when I squeezed it.
Further exam revealed it had split in four places, as can be seen in the attached photo.
I'm asking for advice on what caused the damage, so I can avoid that behavior in the future. I'm presuming one of my 12V batteries was over-charged to 13.8v, or maybe an SWR adjustment using either a T-1 or a ZM-2 'searched' into a damaging SWR range.
Since the radio still seems to function as normal, should I bother to replace L-518?? Rather than risk hole or pad damage, I'd snip this one out, and install a new one wire-to-wire.
I'd appreciate your thoughts/advice.
- Bill? W3WJ
?
?
 

Great reminder and advice, Hans -- thank you !? It shall live on in its present state.
- Bill W3WJ
 

¿ªÔÆÌåÓý

Am I the only one that when I first saw that image, I thought now who used a Hot Dog to make a coil?

Joe WB9SBD

On 8/11/2024 1:27 PM, Hans Summers wrote:

Hi Bill

Always remember: "if it ain't broke, don't fix it!". Ok I know yours actually IS broken but still the radio works fine... So leave it be. Note that the -0 material is permeability zero. It's the same as winding on air. It doesnt even have any magnetic properties to restore by glueing it back together, which would otherwise be the advice on a toroid with actual permeability. The only reason for having the toroid there at all is that you can't easily and repeatably and reliably wind such a nice toroid on air. It just provides a nice convenient shape so that when I say 25 turns it always comes out at approximately similar inductance every time..

73 Hans G0UPL


On Sun, Aug 11, 2024, 20:55 Bill Jobes via <jobes=[email protected]> wrote:
My QMX+, built for 12V version, has been performing well for some weeks.? I decided to tweak the LPF toroids to see if IO could boost power a bit.
Imagine my surprise when L-518, one of two toroids for 10 and 12 meters, felt like mush when I squeezed it.
Further exam revealed it had split in four places, as can be seen in the attached photo.
I'm asking for advice on what caused the damage, so I can avoid that behavior in the future. I'm presuming one of my 12V batteries was over-charged to 13.8v, or maybe an SWR adjustment using either a T-1 or a ZM-2 'searched' into a damaging SWR range.
Since the radio still seems to function as normal, should I bother to replace L-518?? Rather than risk hole or pad damage, I'd snip this one out, and install a new one wire-to-wire.
I'd appreciate your thoughts/advice.
- Bill? W3WJ
?
?
 

Maybe you should "fix it" with bee wax as in good old times.
Bee wax doesn't do change the values or they do?
 

No, but the buzzing is damned annoying.?
--
Wayne S.
KF7RCM
 

¿ªÔÆÌåÓý

Hans, THANK YOU! ?I didn¡¯t build my QMX so wasn¡¯t aware of a 0 type of toroid in the unit¡­.. so you taught an old timer like me something new. ?It makes my day! ?64 years with a license and I am still learning. ?

Be the REASON someone smiles today.

Dave K8WPE

On Aug 11, 2024, at 1:27?PM, Hans Summers <hans.summers@...> wrote:

?
Hi Bill

Always remember: "if it ain't broke, don't fix it!". Ok I know yours actually IS broken but still the radio works fine... So leave it be. Note that the -0 material is permeability zero. It's the same as winding on air. It doesnt even have any magnetic properties to restore by glueing it back together, which would otherwise be the advice on a toroid with actual permeability. The only reason for having the toroid there at all is that you can't easily and repeatably and reliably wind such a nice toroid on air. It just provides a nice convenient shape so that when I say 25 turns it always comes out at approximately similar inductance every time..

73 Hans G0UPL


On Sun, Aug 11, 2024, 20:55 Bill Jobes via <jobes=[email protected]> wrote:
My QMX+, built for 12V version, has been performing well for some weeks.? I decided to tweak the LPF toroids to see if IO could boost power a bit.
Imagine my surprise when L-518, one of two toroids for 10 and 12 meters, felt like mush when I squeezed it.
Further exam revealed it had split in four places, as can be seen in the attached photo.
I'm asking for advice on what caused the damage, so I can avoid that behavior in the future. I'm presuming one of my 12V batteries was over-charged to 13.8v, or maybe an SWR adjustment using either a T-1 or a ZM-2 'searched' into a damaging SWR range.
Since the radio still seems to function as normal, should I bother to replace L-518?? Rather than risk hole or pad damage, I'd snip this one out, and install a new one wire-to-wire.
I'd appreciate your thoughts/advice.
- Bill? W3WJ
?
?
 

I see a splash of tomato sauce in the corner
 

I see a very stale plain Dunkin Donut.?

On Mon, Aug 12, 2024 at 10:09?AM Axel Kohlgrueber via <axelkohlgrueber=[email protected]> wrote:

I see a splash of tomato sauce in the corner

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