With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a good
old fashioned or even new fangled radio, without the noise occurring at some
point. Even from next door one can get it getting into the audio chain.
Anyone know if there is an easy way to stop it. In the old days a few
capacitors got rid of Radio China or Vatican City, but due to the high
frequencies of the phones and the spiky nature of the handshaking noise,
this seems not to work much. What is the mechanism. they cannot be tuned to
the r frequencies, so is it just straight diode type detection due to the
huge signal level?

Low level circuits like turntables, microphone inputs etc, seem to be the
worst, but I've also proved my Denon is picking it up from its speaker
cables.

Brian

--
From the Sofa of Brian Gaff Reply address is active
Remember, if you don't like where I post
or what I say, you don't have to
read my posts! :-)

Top posted because it's Brian.

Looping speaker leads though ferrite clip-on block may fix that entry
route. You may find something similar plus more careful earthing or/and a
filtered mains block would help.

You'd need to say more about the details of your "Low level circuits" for
me to give more specific suggestions. e.g. a 100pF rf cap shunt may help,
but larger caps would be a problem for some inputs like "turntables" (sic).
Maybe you've not tried caps that remain caps at UHF and above?

Diodes might simply make it worse by spraying the energy across into other
frequency bands and pulling more current.

Jim


In article , Brian-Gaff
wrote:
With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a
good old fashioned or even new fangled radio, without the noise
occurring at some point. Even from next door one can get it getting into
the audio chain. Anyone know if there is an easy way to stop it. In the
old days a few capacitors got rid of Radio China or Vatican City, but
due to the high frequencies of the phones and the spiky nature of the
handshaking noise, this seems not to work much. What is the mechanism.
they cannot be tuned to the r frequencies, so is it just straight diode
type detection due to the huge signal level?

Low level circuits like turntables, microphone inputs etc, seem to be
the worst, but I've also proved my Denon is picking it up from its
speaker cables.

Brian

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Hmm well its mostly turntable and microphones into a mixer. It is being
domestic unballanced switchable impedence stuff, so probably not designed
for the problem as the unit was built in 1979 when we did not have mobile
phones. The stuff in throught the two speakers is coming in from next
door, who probably have the sofa up gainst the same wall as my speakers lie
against.
I also have a sub woofer which seems to alsopick it up with no leads
attached at all, so probably the leads inside the box on the amp are doing
the dirty.
I was interested in your comment about the cut of frequency of
capacitorrs, I am a bit out of touch, and most of the ones I fitted before
were of the simi transparent silver innards type.
Brian

--
From the Sofa of Brian Gaff Reply address is active
Remember, if you don't like where I post
or what I say, you don't have to
read my posts! :-)
"Jim Lesurf" wrote in message
...
Top posted because it's Brian.

Looping speaker leads though ferrite clip-on block may fix that entry
route. You may find something similar plus more careful earthing or/and a
filtered mains block would help.

You'd need to say more about the details of your "Low level circuits" for
me to give more specific suggestions. e.g. a 100pF rf cap shunt may help,
but larger caps would be a problem for some inputs like "turntables"
(sic).
Maybe you've not tried caps that remain caps at UHF and above?

Diodes might simply make it worse by spraying the energy across into other
frequency bands and pulling more current.

Jim


In article , Brian-Gaff
wrote:
With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a
good old fashioned or even new fangled radio, without the noise
occurring at some point. Even from next door one can get it getting into
the audio chain. Anyone know if there is an easy way to stop it. In the
old days a few capacitors got rid of Radio China or Vatican City, but
due to the high frequencies of the phones and the spiky nature of the
handshaking noise, this seems not to work much. What is the mechanism.
they cannot be tuned to the r frequencies, so is it just straight diode
type detection due to the huge signal level?

Low level circuits like turntables, microphone inputs etc, seem to be
the worst, but I've also proved my Denon is picking it up from its
speaker cables.

Brian

--
Please use the address on the audiomisc page if you wish to email me.
Electronics
http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article ,
Brian-Gaff wrote:
With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a
good old fashioned or even new fangled radio, without the noise
occurring at some point. Even from next door one can get it getting into
the audio chain. Anyone know if there is an easy way to stop it. In the
old days a few capacitors got rid of Radio China or Vatican City, but
due to the high frequencies of the phones and the spiky nature of the
handshaking noise, this seems not to work much. What is the mechanism.
they cannot be tuned to the r frequencies, so is it just straight diode
type detection due to the huge signal level?

Low level circuits like turntables, microphone inputs etc, seem to be
the worst, but I've also proved my Denon is picking it up from its
speaker cables.

You seem to be very unlucky or live in an odd area or have odd equipment
if you're picking up interference on a pickup or mic?

My laptop reports some 20 Wi-Fi signals at usable level round here, but no
problems on the Hi-Fi here. Or with mobile phones which I'd guess are as
common as the above.

Obviously, roaming the radio waves for distant and obscure stuff might be
a different matter.

--
*The fact that no one understands you doesn't mean you're an artist

Dave Plowman London SW
To e-mail, change noise into sound.

On 21/11/2015 14:34, Dave Plowman (News) wrote:
In article ,
Brian-Gaff wrote:
With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a
good old fashioned or even new fangled radio, without the noise
occurring at some point. Even from next door one can get it getting into
the audio chain. Anyone know if there is an easy way to stop it. In the
old days a few capacitors got rid of Radio China or Vatican City, but
due to the high frequencies of the phones and the spiky nature of the
handshaking noise, this seems not to work much. What is the mechanism.
they cannot be tuned to the r frequencies, so is it just straight diode
type detection due to the huge signal level?

Low level circuits like turntables, microphone inputs etc, seem to be
the worst, but I've also proved my Denon is picking it up from its
speaker cables.

You seem to be very unlucky or live in an odd area or have odd equipment
if you're picking up interference on a pickup or mic?

My laptop reports some 20 Wi-Fi signals at usable level round here, but no
problems on the Hi-Fi here. Or with mobile phones which I'd guess are as
common as the above.

Obviously, roaming the radio waves for distant and obscure stuff might be
a different matter.


FWIW, my iPhone's 'polling' (not sure how, what or why) can be heard on
my hifi, FM radios, and work's PA systems in lecture halls. It's a sort
of chirping, and lasts about 10s.

--
Cheers, Rob

In article ,
RJH wrote:
You seem to be very unlucky or live in an odd area or have odd
equipment if you're picking up interference on a pickup or mic?

My laptop reports some 20 Wi-Fi signals at usable level round here,
but no problems on the Hi-Fi here. Or with mobile phones which I'd
guess are as common as the above.

Obviously, roaming the radio waves for distant and obscure stuff might
be a different matter.


FWIW, my iPhone's 'polling' (not sure how, what or why) can be heard on
my hifi, FM radios, and work's PA systems in lecture halls. It's a sort
of chirping, and lasts about 10s.

Yes - that does happen, but moving the phone away a few feet should sort
it.

It used to happen frequently on live radio etc broadcasts despite those in
the studio being told to turn off any phones. Rather than go to silent.
It's far less common these days, so something has changed.

--
*Reality is a crutch for people who can't handle drugs.

Dave Plowman London SW
To e-mail, change noise into sound.

On 22/11/2015 10:41, Dave Plowman (News) wrote:
In article ,
RJH wrote:
You seem to be very unlucky or live in an odd area or have odd
equipment if you're picking up interference on a pickup or mic?

My laptop reports some 20 Wi-Fi signals at usable level round here,
but no problems on the Hi-Fi here. Or with mobile phones which I'd
guess are as common as the above.

Obviously, roaming the radio waves for distant and obscure stuff might
be a different matter.


FWIW, my iPhone's 'polling' (not sure how, what or why) can be heard on
my hifi, FM radios, and work's PA systems in lecture halls. It's a sort
of chirping, and lasts about 10s.

Yes - that does happen, but moving the phone away a few feet should sort
it.

It used to happen frequently on live radio etc broadcasts despite those in
the studio being told to turn off any phones. Rather than go to silent.
It's far less common these days, so something has changed.


It was worse with analogue phones IIRC. Used to get it a lot on RTB
feeds on OBs

--
Graeme Wall
This account not read, substitute trains for rail.

In article ,
Graeme Wall wrote:
Yes - that does happen, but moving the phone away a few feet should
sort it.

It used to happen frequently on live radio etc broadcasts despite
those in the studio being told to turn off any phones. Rather than go
to silent. It's far less common these days, so something has changed.


It was worse with analogue phones IIRC. Used to get it a lot on RTB
feeds on OBs

You've got me confused now. ;-) My first phone - 1992 - was a Technophone
analogue, and that didn't induce the chirping noise. It was replaced (when
the service stopped) with a Nokia, and that did. I still have it, and it
still works, so I assume was on the current digital system?

I do remember it causing a problem on a Calrec analogue sound desk while
clipped to my waistband. Moving it a few feet away sorted it.

--
*Seen it all, done it all, can't remember most of it*

Dave Plowman London SW
To e-mail, change noise into sound.

In article , RJH wrote:

FWIW, my iPhone's 'polling' (not sure how, what or why) can be heard on
my hifi, FM radios, and work's PA systems in lecture halls. It's a sort
of chirping, and lasts about 10s.

We don't get any problems from phones, etc, even when using one in the same
room. This is despite a lot of the kit I use being pretty old - i.e. like
me!

I always fitted an RC at the input to amps and a full Zobel (series
inductor/resistor as well as shunt cap/resistor) to help block crap getting
in. I also put caps across all four mains bridge diodes and across the
mains input.

On 22 Nov in uk.rec.audio, Woody wrote:
In many cases putting a loop or two the speaker cable through a ferrite
ring will kill the interference dead, but have you tried buying ferrite
rings these days? At one time they were easily obtained and in many
varieties but now - lets us say rocking horse manure comes to mind.

FWIW I buy rings from CPC. I'd echo that they often deal with garbage
picked up from the speaker leads. As you only have to wind the lead though
them they are an easy fix for people to try.

The Armstrong 626 I had refurbished recently was an early version. These
were prone to clicks, etc. The first impression might be that they were
getting in via the mains. They also have a wooden lid and plastic base, so
are exposed to external fields. (Unless you line them with ali foil or
mu-metal!) But experiment showed me that it was via speaker leads. Solved
with ferrite clip-on blocks/rings.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Brian-Gaff wrote:


With the proliferisation of mobile devices running on the mobile phone
network its getting increasingly a annoying to listen to things on a good
old fashioned or even new fangled radio, without the noise occurring at some
point. Even from next door one can get it getting into the audio chain.
Anyone know if there is an easy way to stop it.



** There is no easy way.

In the old days a few
capacitors got rid of Radio China or Vatican City, but due to the high
frequencies of the phones and the spiky nature of the handshaking noise,
this seems not to work much. What is the mechanism. they cannot be tuned to
the r frequencies, so is it just straight diode type detection due to the
huge signal level?



** At a range of a few metres, the induced signal is hundreds of millivolts..
Rectification by a non linear component produces a small DC level and when the RF signal is 100% amplitude modulated at an audio frequency causes the buzzing noise. GSM phones are the worst.


Low level circuits like turntables, microphone inputs etc, seem to be the
worst, but I've also proved my Denon is picking it up from its speaker
cables.


** The standard technique is to reduce RF energy entering a device via input and output leads by making sure the shields are grounded to the metal case right at the connectors. A 10nF ceramic cap wired direct to chassis from the ground pin of the connector normally does the trick. The same can also be done with both speaker terminals.

I helps if all co-axial signal cables have woven shields.

If the device does not have a metal case, you are outta luck.


.... Phil