开云体育

I'm assembling a QMX+, and all those on-end toroids look a bit fragile to me. They get pushed about as I merely install each new toroid. Yes, they'll all be inside a case in the completed unit, but I still wonder if they might be microphonic or suffer from mechanical shock (for example, if the radio is dropped during travel, even in an outer container).

?

So I'm considering tacking the toroids down with beads of hot glue or RTV (the kind that doesn't outgas acetic acid, of course). Is this likely to affect the performance of the circuits, or to be a Bad Idea for reasons I haven't thought of?

?

Thanks,

Steve N1XNX

I have used a dab of hot glue on board connectors and don’t recommend it. I would try wax next time or maybe even white glue. Hot glue might melt insulation and I used it because I mistakenly thought I would never need to take it loose. I had to desolder the pins and replace wires and header. Luckily no other parts were damaged. I would try dripping wax on a spare toroid first.?
73s John N4HNO

Gluing them makes them really difficult to work on later. Make sure you have them adjusted properly before gluing if you do that.? I don’t personally glue them because their inductance and therefore the filter performance doesn’t significantly change with orientation. And if it was necessary it would probably be a step in the assembly instructions. I’ve had to work on a few that were glued and it is a mess. Just my thoughts.?

73… Ron

Hi,

I agree with Ron. I put the the QMX+ through a shake and drop test

and? glue is not necessary. The little inductors are more fragile anyway.

A cell phone is even more fragile than a QMX+.? ?Don't drop it!?

73,

George

Hot glue is pain to remove if needed.

?

Instead use B6000 or 7000 glue, holds just right not toxic to components, and easy to remove with just a small swipe of alcohole.

?

Do not use silicone since it can cause corosion.

It's probably not necessary on QMX+

I have done it frequently with the old U3S etc plug-in bandpass /low pass filters as these do get quite a lot of handling during active use.? ? Several breakages before, Never had a breakage since.

On those filters there is always a winding free area between the PCB connections and I find a blob of araldite rapid across the toroid to-from the board either side works well and the tune doesn't shift.
I do it with the VNA still connected so I can say that with confidence?
? ?
I sometimes I've also put a very small thin /light blob as a 'cap' across the top of the winding to avoid the turns there being disturbed when handled.? ?Again no de-tuning seen

?

This is all on a different radio that will be messed with on a weekly basis though but I think the technique will be transferrable..??

While they are positioned differently in the QMX, I did see suggestions for glue.? Haven't used glue and have no adverse effects.? If you watch a video of Hans adjusting a QCX, you can see toroids being pushed every which way and he doesn't seem concerned.

?

Good luck with your build. These are AMAZING little radios!

--

72 de N4REE, Bob Easton - QRP CW forever

Rubbing alcohol will release hot glue. BUT on a torroid with wire wrapped around it, it will be more difficult. I don't think its hot enough to damage the coatings though.If you use it do so in moderation and try not to get it in the hole as its much harder to get it out than just a dab on the bottom side.

I have used a couple tiny drops of fingernail polish on my touchy band pass filters to help hold windings in place. Its strong enough to hold winding still if you brush it with your hand, but can easily be snapped loose if an adjustment is needed later for some reason. Again Dont drench it.

?

In fact, just last week I was trouble shooting a problem with my qcx+. L1 had been inadvertantly bumped around so much that one leg did break off, so your concern is somewhat valid if you are not careful. Fortunately It was solderd to the top side and repair was easy. (HINT HINT)

--

regards,
Bryan, N0LUF

I can’t paste a link but if you search: NASA-STD-8739.1 It will take you to a wonderful PDF that explains everything to do with staking down electronic components.

Here:?

?

A good visual guide to soldering:?

?

73, Don N2VGU

I hot glued a number of my toroids and it has not had any discernable effect on performance.? I was mostly concerned about the ones standing one and to keep another from sliding horizontally into a tabbed semiconductor device.? I used it sparingly.? Theoretically the introduction of dielectric material between turns can increase turn to turn capacitance which can affect coil Q, but a dab here or there should not have significant effect.

?

Brien - KE7WB

Great visual guide to soldering.? Thanks for posting !

Jim WB4ILP?

Personally I would not glue the toroids down with anything.

The only thing I do when I install a toroid is I pull the wires down snuggly when I solder them so that they’re pulled against the board firmly and that’s it.

i’ve built 4 QRP lab kits and never had an issue with the Toroids.

if you glue them it only makes any future adjustments or rework very difficult.

If it isn’t in the manual don’t do it.