[Arpiben]

Changing hat...

Copper foil (rather than aluminium) is commonly used as a workaround to reduce EMI:

• radiating from device / connectors / cables / transitions / waveguides / etc...
• entering from noisy environment towards the same device / connectors / cables / transitions / waveguides / etc...

In principle, copper foil is used in small quantity and is properly grounded.

When having no idea at all about what to suppress and how, I would suggest not to play with any foil at all since odds are great that you will end up by worsening things in terms of noise.
Dealing with Power cables shielding as per this thread title I seriously doubt of any benefit with the 30 feet length foil since if the AC/DC source is noisy the foil will not prevent it to enter to the plugged devices.

 

[ScareDe2]

I seriously doubt of any benefit

But you don't give the benefit of the doubt.

:sadface:

 

[Arpiben]

But you don't give the benefit of the doubt.

:sadface:

Well looking at it in a different way I may have added that the probable added noise your are catching with your Alu foils is giving you a more pleasant listening experience.
I am afraid we can't go further both of us. :sadface:

 

[ScareDe2]

Well looking at it in a different way I may have added that the probable added noise your are catching with your Alu foils is giving you a more pleasant listening experience.
I am afraid we can't go further both of us. :sadface:

At least we probably agree that we can catch noise with cables.

 

[pinnahertz]

Changing hat...

Copper foil (rather than aluminium) is commonly used as a workaround to reduce EMI:

• radiating from device / connectors / cables / transitions / waveguides / etc...
• entering from noisy environment towards the same device / connectors / cables / transitions / waveguides / etc...

In principle, copper foil is used in small quantity and is properly grounded.

When having no idea at all about what to suppress and how, I would suggest not to play with any foil at all since odds are great that you will end up by worsening things in terms of noise.
Dealing with Power cables shielding as per this thread title I seriously doubt of any benefit with the 30 feet length foil since if the AC/DC source is noisy the foil will not prevent it to enter to the plugged devices.

There is probably more aluminum-polyester foil cable shielding in use in the world now than copper. IIR, the original product was introduced ny Belden in the 1960s, called Beldfoil. Cables that use it include a drain wire so the foil shield can be electrically bonded at cable ends. Aluminum-polyester foil shields are the most common shield types found in installed cabling of all types, from multi-pair with individual and overall shields, to “quad shield” and “double shield” RF coax like RG6 and RG59. Low leak Quad-shield makes todays high speed digital cable TV systems possible, but it’s used everywhere. Foil shielding in cable makes 100% shielding possible while retaining cable flexibility. However, where cable flexibility or repeated bending is required, like for hand-held microphones for example, a copper braid or spiral is preferred for its long term reliability and somewhat lower handling noise.

Might be worth noting that cable shielding of any kind creates an electromagnetic and electrostatic barrier but is magnetically transparent. That means it has zero effect on inductive noise pickup.

 

[Arpiben]

1.There is probably more aluminum-polyester foil cable shielding in use in the world now than copper. IIR, the original product was introduced ny Belden in the 1960s, called Beldfoil. Cables that use it include a drain wire so the foil shield can be electrically bonded at cable ends. Aluminum-polyester foil shields are the most common shield types found in installed cabling of all types, from multi-pair with individual and overall shields, to “quad shield” and “double shield” RF coax like RG6 and RG59. Low leak Quad-shield makes todays high speed digital cable TV systems possible, but it’s used everywhere. Foil shielding in cable makes 100% shielding possible while retaining cable flexibility. However, where cable flexibility or repeated bending is required, like for hand-held microphones for example, a copper braid or spiral is preferred for its long term reliability and somewhat lower handling noise.

2.Might be worth noting that cable shielding of any kind creates an electromagnetic and electrostatic barrier but is magnetically transparent. That means it has zero effect on inductive noise pickup.

1. Right. I was having in mind the copper rubber foil you add on top of not the cable shield itself. Anyway thanks for clarifying.
2. Right excluding hollow cables / waveguides (out of audio applications)

 

[bigshot]

I don't know much about this stuff, but it's been my experience that RF and grounding problems are either there or they aren't. It isn't the sort of thing that you can make small incremental improvements to. If you aren't hearing obvious noise, I wouldn't worry about it.

 

[pinnahertz]

I don't know much about this stuff, but it's been my experience that RF and grounding problems are either there or they aren't. It isn't the sort of thing that you can make small incremental improvements to.

Nah, it reality it can be very incremental. Good for you if you haven't had to deal with RF! Trying to get great audio working when you're surrounded by 10 FMs and 5 TVs is a bit of a different story. But the real fun was keeping audio clean at a 50kW AM transmitter site. Sheesh. You just keep beating it into submission, an increment at a time. Shields sometimes become a point of entry.

However, most home audio folk don't get RFI, they misidentify noise as RF when it's actually something else.

If you aren't hearing obvious noise, I wouldn't worry about it.

Yup. If it ain't broke, don't fix it.

 

[castleofargh]

metal has funky properties with a lot of waves, from possibly reflecting some wifi signal, to polarization of light. but before discussing what's going on, we have a dire need of information. like what waves(wavelength)? and what do we do with the improvised shield(grounded or not? where?)? those 2 parameters alone could pretty much turn a shield into an antenna, having the very opposite of the effect desired.
I made people laugh some years back on a french forum with a portable amp where I could tell if a cellphone was sending stuff like 5meters away from me in another room(a nightmare). and I greatly reduced the noise grabbing and amplifying issue with... an empty box of Pringles(audiophile taste). so sometimes, funny stuff like that do happen and the guys with the aluminum hats to stop aliens or the CIA from probing their mind are on to something, maybe... ^_^

my issue in general with shielding in audio is where do we solder it? can I be sure that the picked up noise won't end up back in the audio loop? some stuff are made with a clear ground for the job and the cable is expected to be shielded, but other times we are in situations like a headphone cable, do we solder, or leave it be? is it even relevant to have a shield there? then different gears may have different designs for ground. there can also be the matter of how close that improvised shield comes to the signal's wires, and if they end up having some electrical impact on it. we could add the total surface of the DIY shield, the bigger it is the bigger whatever noise getting into it.
all in all I'm with Arpi and the rest, if there isn't a clear issue, I would leave it alone. and if curiosity takes over like it often does for me, I'd make sure to measure my output to at least check that I'm not making making things worst.

 

[Zapp_Fan]

I had some SNR problems on my cable modem. I found that the coax cable had some holes in the foil shielding, so I wrapped some aluminum foil around it. My internet started working again, although I am not sure if the two events are related. The cable modem did report better SNR, but I was also jiggling the cable around and messing with the contacts. Not exactly hard science.

 

[pinnahertz]

I had some SNR problems on my cable modem. I found that the coax cable had some holes in the foil shielding, so I wrapped some aluminum foil around it. My internet started working again, although I am not sure if the two events are related. The cable modem did report better SNR, but I was also jiggling the cable around and messing with the contacts. Not exactly hard science.

You're describe connection quality issues, not shielding problems caused a hole in the foil, assuming the whole wasn't a foot long or so. Type F connectors on RG6 cable are notorious for trouble, unless they are high quality compression "snap/seal" types. Re-terminating cable is one of the first things a tech would do to troubleshoot connection and issues. If that hasn't been done, it should be.

 

[Zapp_Fan]

You're describe connection quality issues, not shielding problems caused a hole in the foil, assuming the whole wasn't a foot long or so. Type F connectors on RG6 cable are notorious for trouble, unless they are high quality compression "snap/seal" types. Re-terminating cable is one of the first things a tech would do to troubleshoot connection and issues. If that hasn't been done, it should be.

You're probably right about that. IIRC ultimately cleaning and re-tightening all the outdoor connections helped more.

 

[Arpiben]

You're probably right about that. IIRC ultimately cleaning and re-tightening all the outdoor connections helped more.

Dealing with outdoor connectors you may protect them against humidity/rain with self adhesive rubber gum ( auto amalgamating).

 

[pinnahertz]

Dealing with outdoor connectors you may protect them against humidity/rain with self adhesive rubber gum ( auto amalgamating).

And if you can't find that, just vinyl electrical tape will help them stay cleaner longer. Just wrap it tightly so it forms over the connector and wire. If you use the snap/seal connectors, just tape over the connector, the wire is already sealed.

I use the "coax-seal" tape. I have the huge, wide roll, but this works too.

 

[Speedskater]

a] Thin aluminum foil or tape is an excellent shield material at high radio frequencies. With braided copper being a better shield at lower frequencies.
b] But while it might be a shield, it could be a reflector or an interference antenna. It's hard to tell without analyzing the circuit and the set-up.
c] It's difficult to connect to other metals.

It's unlikely that a good hi-fi system will have a problem that aluminum foil will solve.