Mixing
EM waves and cable shields
Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
After reading about cable screens to prevent electric field interference such as:
“Most of our audio cables are screened, and this does a decent job in
keeping the Radio Frequencies at bay, but doesn’t do anything much to
keep out the signals that we can hear, because these attack our audio
largely by long wave length electromagnetic fields which go straight
through the expensive foil wrap and braided screen protection around
our cables.â€Â
How can low frequency interference such as 50/60Hz long wave due to mains electricity pass through the a coaxial cable shield but not high freq. EM waves like radio waves?
electromagnetic-radiation
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
favorite
After reading about cable screens to prevent electric field interference such as:
“Most of our audio cables are screened, and this does a decent job in
keeping the Radio Frequencies at bay, but doesn’t do anything much to
keep out the signals that we can hear, because these attack our audio
largely by long wave length electromagnetic fields which go straight
through the expensive foil wrap and braided screen protection around
our cables.â€Â
How can low frequency interference such as 50/60Hz long wave due to mains electricity pass through the a coaxial cable shield but not high freq. EM waves like radio waves?
electromagnetic-radiation
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
After reading about cable screens to prevent electric field interference such as:
“Most of our audio cables are screened, and this does a decent job in
keeping the Radio Frequencies at bay, but doesn’t do anything much to
keep out the signals that we can hear, because these attack our audio
largely by long wave length electromagnetic fields which go straight
through the expensive foil wrap and braided screen protection around
our cables.â€Â
How can low frequency interference such as 50/60Hz long wave due to mains electricity pass through the a coaxial cable shield but not high freq. EM waves like radio waves?
electromagnetic-radiation
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
After reading about cable screens to prevent electric field interference such as:
“Most of our audio cables are screened, and this does a decent job in
keeping the Radio Frequencies at bay, but doesn’t do anything much to
keep out the signals that we can hear, because these attack our audio
largely by long wave length electromagnetic fields which go straight
through the expensive foil wrap and braided screen protection around
our cables.â€Â
How can low frequency interference such as 50/60Hz long wave due to mains electricity pass through the a coaxial cable shield but not high freq. EM waves like radio waves?
electromagnetic-radiation
electromagnetic-radiation
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 5 hours ago
newage2000
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 5 hours ago
newage2000
111
asked 5 hours ago
newage2000
111
111
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
newage2000 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
add a comment |Â
3 Answers
3
active
oldest
votes
up vote
2
down vote
The skin effect means that fields of high frequency penetrate less deep into conductors than fields of low frequency.
answered 4 hours ago
my2cts
3,5362416
add a comment |Â
up vote
1
down vote
after having used high-impedance shielded cable runs for audio and live on-stage performance for 48 years, I can say from direct experience that the assertion you referenced is wrong. in fact the primary purpose of shielded cables in audio apps is to block 1) radiated interference from things like fluorescent light fixtures and some neon bulbs (60Hz plus higher harmonics), 2) radiated interference from silicon-controlled rectifiers ("light dimmers", also 60Hz plus higher harmonics) and 3) crosstalk from adjacent audio cables carrying signals to and from speakers, amplifiers and preamplifiers (in the full audio range).
in fact, the way you detect a shielding fault when it occurs is a sudden and very audible increase in the amount of audible hum and buzz getting into the signal path.
the RF shielding effect is important too, but only if you are in the vicinity of a large radio transmitting antenna or if your upstairs neighbor is a poorly-educated CB or ham radio enthusiast.
answered 4 hours ago
niels nielsen
11.4k41833
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
 |Â
show 2 more comments
up vote
1
down vote
You can radiate 60Hz EM quite easily at 120v and 10amps for example, but as Nielsen shows in many instances it is from ac switching devices that actually produce a white noise (composed of many high frequencies) similar to a spark noise (but not a spark). Most home speakers do not use shielded cable, it's only on the inputs from dvd players etc where coax is present, and this prevents rf as well as 60Hz. If these input cables get too long you can pick up the 60Hz and the white noise which when amplified is bad. I have no experience in stage wiring but these cables can be long which would help pickup even on speaker cables, also there may me a mix of speaker cables and microphone cables that could cross talk. Also many times the white noise gets carried on the powervlines directly into amps.
answered 1 hour ago
PhysicsDave
59426
add a comment |Â
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
The skin effect means that fields of high frequency penetrate less deep into conductors than fields of low frequency.
answered 4 hours ago
my2cts
3,5362416
add a comment |Â
up vote
2
down vote
The skin effect means that fields of high frequency penetrate less deep into conductors than fields of low frequency.
answered 4 hours ago
my2cts
3,5362416
add a comment |Â
up vote
2
down vote
up vote
2
down vote
The skin effect means that fields of high frequency penetrate less deep into conductors than fields of low frequency.
answered 4 hours ago
my2cts
3,5362416
The skin effect means that fields of high frequency penetrate less deep into conductors than fields of low frequency.
answered 4 hours ago
my2cts
3,5362416
answered 4 hours ago
my2cts
3,5362416
answered 4 hours ago
my2cts
3,5362416
answered 4 hours ago
my2cts
3,5362416
3,5362416
add a comment |Â
add a comment |Â
up vote
1
down vote
after having used high-impedance shielded cable runs for audio and live on-stage performance for 48 years, I can say from direct experience that the assertion you referenced is wrong. in fact the primary purpose of shielded cables in audio apps is to block 1) radiated interference from things like fluorescent light fixtures and some neon bulbs (60Hz plus higher harmonics), 2) radiated interference from silicon-controlled rectifiers ("light dimmers", also 60Hz plus higher harmonics) and 3) crosstalk from adjacent audio cables carrying signals to and from speakers, amplifiers and preamplifiers (in the full audio range).
in fact, the way you detect a shielding fault when it occurs is a sudden and very audible increase in the amount of audible hum and buzz getting into the signal path.
the RF shielding effect is important too, but only if you are in the vicinity of a large radio transmitting antenna or if your upstairs neighbor is a poorly-educated CB or ham radio enthusiast.
answered 4 hours ago
niels nielsen
11.4k41833
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
 |Â
show 2 more comments
up vote
1
down vote
after having used high-impedance shielded cable runs for audio and live on-stage performance for 48 years, I can say from direct experience that the assertion you referenced is wrong. in fact the primary purpose of shielded cables in audio apps is to block 1) radiated interference from things like fluorescent light fixtures and some neon bulbs (60Hz plus higher harmonics), 2) radiated interference from silicon-controlled rectifiers ("light dimmers", also 60Hz plus higher harmonics) and 3) crosstalk from adjacent audio cables carrying signals to and from speakers, amplifiers and preamplifiers (in the full audio range).
in fact, the way you detect a shielding fault when it occurs is a sudden and very audible increase in the amount of audible hum and buzz getting into the signal path.
the RF shielding effect is important too, but only if you are in the vicinity of a large radio transmitting antenna or if your upstairs neighbor is a poorly-educated CB or ham radio enthusiast.
answered 4 hours ago
niels nielsen
11.4k41833
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
 |Â
show 2 more comments
up vote
1
down vote
up vote
1
down vote
after having used high-impedance shielded cable runs for audio and live on-stage performance for 48 years, I can say from direct experience that the assertion you referenced is wrong. in fact the primary purpose of shielded cables in audio apps is to block 1) radiated interference from things like fluorescent light fixtures and some neon bulbs (60Hz plus higher harmonics), 2) radiated interference from silicon-controlled rectifiers ("light dimmers", also 60Hz plus higher harmonics) and 3) crosstalk from adjacent audio cables carrying signals to and from speakers, amplifiers and preamplifiers (in the full audio range).
in fact, the way you detect a shielding fault when it occurs is a sudden and very audible increase in the amount of audible hum and buzz getting into the signal path.
the RF shielding effect is important too, but only if you are in the vicinity of a large radio transmitting antenna or if your upstairs neighbor is a poorly-educated CB or ham radio enthusiast.
answered 4 hours ago
niels nielsen
11.4k41833
after having used high-impedance shielded cable runs for audio and live on-stage performance for 48 years, I can say from direct experience that the assertion you referenced is wrong. in fact the primary purpose of shielded cables in audio apps is to block 1) radiated interference from things like fluorescent light fixtures and some neon bulbs (60Hz plus higher harmonics), 2) radiated interference from silicon-controlled rectifiers ("light dimmers", also 60Hz plus higher harmonics) and 3) crosstalk from adjacent audio cables carrying signals to and from speakers, amplifiers and preamplifiers (in the full audio range).
in fact, the way you detect a shielding fault when it occurs is a sudden and very audible increase in the amount of audible hum and buzz getting into the signal path.
the RF shielding effect is important too, but only if you are in the vicinity of a large radio transmitting antenna or if your upstairs neighbor is a poorly-educated CB or ham radio enthusiast.
answered 4 hours ago
niels nielsen
11.4k41833
answered 4 hours ago
niels nielsen
11.4k41833
answered 4 hours ago
niels nielsen
11.4k41833
answered 4 hours ago
niels nielsen
11.4k41833
11.4k41833
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
 |Â
show 2 more comments
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
At 60Hz there is no wave there is electric field or magnetic field. At that freq the interference is not EM wva but the field. You need a huge antenna to receive 60Hz as a wave.
– newage2000
4 hours ago
1
1
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
no, you don't. this is easily demonstrated with a guitar amp and an electric guitar with unshielded pickups, feeding an oscilloscope.
– niels nielsen
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
I was just pointing out what you call radiation interference is not radiation it is field
– newage2000
4 hours ago
1
1
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
I am a ham radio operator. we call any signal carried by electromagnetic waves (which are time-varying electromagnetic fields) "radiation".
– niels nielsen
4 hours ago
1
1
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
to get a good impedance match between the antenna and free space, that is true. you do not need a good impedance match to radiate. a poor match will work.
– niels nielsen
4 hours ago
 |Â
show 2 more comments
up vote
1
down vote
You can radiate 60Hz EM quite easily at 120v and 10amps for example, but as Nielsen shows in many instances it is from ac switching devices that actually produce a white noise (composed of many high frequencies) similar to a spark noise (but not a spark). Most home speakers do not use shielded cable, it's only on the inputs from dvd players etc where coax is present, and this prevents rf as well as 60Hz. If these input cables get too long you can pick up the 60Hz and the white noise which when amplified is bad. I have no experience in stage wiring but these cables can be long which would help pickup even on speaker cables, also there may me a mix of speaker cables and microphone cables that could cross talk. Also many times the white noise gets carried on the powervlines directly into amps.
answered 1 hour ago
PhysicsDave
59426
add a comment |Â
up vote
1
down vote
You can radiate 60Hz EM quite easily at 120v and 10amps for example, but as Nielsen shows in many instances it is from ac switching devices that actually produce a white noise (composed of many high frequencies) similar to a spark noise (but not a spark). Most home speakers do not use shielded cable, it's only on the inputs from dvd players etc where coax is present, and this prevents rf as well as 60Hz. If these input cables get too long you can pick up the 60Hz and the white noise which when amplified is bad. I have no experience in stage wiring but these cables can be long which would help pickup even on speaker cables, also there may me a mix of speaker cables and microphone cables that could cross talk. Also many times the white noise gets carried on the powervlines directly into amps.
answered 1 hour ago
PhysicsDave
59426
add a comment |Â
up vote
1
down vote
up vote
1
down vote
You can radiate 60Hz EM quite easily at 120v and 10amps for example, but as Nielsen shows in many instances it is from ac switching devices that actually produce a white noise (composed of many high frequencies) similar to a spark noise (but not a spark). Most home speakers do not use shielded cable, it's only on the inputs from dvd players etc where coax is present, and this prevents rf as well as 60Hz. If these input cables get too long you can pick up the 60Hz and the white noise which when amplified is bad. I have no experience in stage wiring but these cables can be long which would help pickup even on speaker cables, also there may me a mix of speaker cables and microphone cables that could cross talk. Also many times the white noise gets carried on the powervlines directly into amps.
answered 1 hour ago
PhysicsDave
59426
You can radiate 60Hz EM quite easily at 120v and 10amps for example, but as Nielsen shows in many instances it is from ac switching devices that actually produce a white noise (composed of many high frequencies) similar to a spark noise (but not a spark). Most home speakers do not use shielded cable, it's only on the inputs from dvd players etc where coax is present, and this prevents rf as well as 60Hz. If these input cables get too long you can pick up the 60Hz and the white noise which when amplified is bad. I have no experience in stage wiring but these cables can be long which would help pickup even on speaker cables, also there may me a mix of speaker cables and microphone cables that could cross talk. Also many times the white noise gets carried on the powervlines directly into amps.
answered 1 hour ago
PhysicsDave
59426
answered 1 hour ago
PhysicsDave
59426
answered 1 hour ago
PhysicsDave
59426
answered 1 hour ago
PhysicsDave
59426
59426
add a comment |Â
add a comment |Â
newage2000 is a new contributor. Be nice, and check out our Code of Conduct.
newage2000 is a new contributor. Be nice, and check out our Code of Conduct.
newage2000 is a new contributor. Be nice, and check out our Code of Conduct.
newage2000 is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f432987%2fem-waves-and-cable-shields%23new-answer', 'question_page');
);
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password