RFI on phone line - ferrite cores?

Does anyone think that clip on ferrite cores might help reducing RFI from a
phone line? I know I should just try it, but wondered if anyone had already
stopped RF interference using them? The interference is being caused by a
local radio ham, who I am on good terms with and who has offered to help
cure the problem.

Glenn Myers wrote:
> Does anyone think that clip on ferrite cores might help reducing RFI from a
> phone line? I know I should just try it, but wondered if anyone had already
> stopped RF interference using them? The interference is being caused by a
> local radio ham, who I am on good terms with and who has offered to help
> cure the problem.
>
>
>
of course. I will block the RFI. And the broadband, of course, but hey,
who cares?

Kráftéé wrote:
> Glenn Myers wrote:
>> Does anyone think that clip on ferrite cores might help reducing RFI
>> from a phone line? I know I should just try it, but wondered if
>> anyone had already stopped RF interference using them? The
>> interference is being caused by a local radio ham, who I am on good
>> terms with and who has offered to help cure the problem.
>
> First thing to try would be a RF filter on the line or even a plugin
> RF filter. Be aware that the usage of such things could affect your
> broadband if used incorrectly just as using any of the tried & tested
> solutions from the 'Hams' arsenal could do.
>
>
Mot of the intereference on long broadband lines IS RF ..Broadband IS
RF..noise.

How anyone can epect to filter RFI out of the line without removing the
broadband, beats me.

What band is the ham on?

"The Natural Philosopher" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Kráftéé wrote:
> > Glenn Myers wrote:
> >> Does anyone think that clip on ferrite cores might help reducing RFI
> >> from a phone line? I know I should just try it, but wondered if
> >> anyone had already stopped RF interference using them? The
> >> interference is being caused by a local radio ham, who I am on good
> >> terms with and who has offered to help cure the problem.
> >
> > First thing to try would be a RF filter on the line or even a plugin
> > RF filter. Be aware that the usage of such things could affect your
> > broadband if used incorrectly just as using any of the tried & tested
> > solutions from the 'Hams' arsenal could do.
> >
> >
> Mot of the intereference on long broadband lines IS RF ..Broadband IS
> RF..noise.
>
> How anyone can epect to filter RFI out of the line without removing the
> broadband, beats me.
>
> What band is the ham on?


3500 KHz

On Sun, 01 Feb 2009 12:51:35 +0000, Krft faxed us with....

> Glenn Myers wrote:
>> Does anyone think that clip on ferrite cores might help reducing RFI
>> from a phone line? I know I should just try it, but wondered if anyone
>> had already stopped RF interference using them? The interference is
>> being caused by a local radio ham, who I am on good terms with and who
>> has offered to help cure the problem.
>
> First thing to try would be a RF filter on the line or even a plugin RF
> filter. Be aware that the usage of such things could affect your
> broadband if used incorrectly just as using any of the tried & tested
> solutions from the 'Hams' arsenal could do.

And broadband does not operate up to the lower end of RF spectrum at all
then? Mmmm. You are starting to scare me.

--
Replica Watches - TRY LIDL - Cheap meds? Visit your GP

In message <(E-Mail Removed)>, Glenn Myers
<rty57utr@547uuky8.342> wrote
>Does anyone think that clip on ferrite cores might help reducing RFI from a
>phone line? I know I should just try it, but wondered if anyone had already
>stopped RF interference using them? The interference is being caused by a
>local radio ham, who I am on good terms with and who has offered to help
>cure the problem.
>

It's probably not only you with the compromised broadband but also your
neighbours and the rest of the local area?
--
Alan
news2006 {at} amac {dot} f2s {dot} com

On Sun, 1 Feb 2009 12:11:19 -0000, "Glenn Myers" <rty57utr@547uuky8.342> wrote:

>Does anyone think that clip on ferrite cores might help reducing RFI from a
>phone line? I know I should just try it, but wondered if anyone had already
>stopped RF interference using them?

Which piece of your equipment is receiving the signal?
If it is a telephone then try filetering the cable to your device.

--
Geo

The Natural Philosopher wrote:
>>
> Mot of the intereference on long broadband lines IS RF ..Broadband IS
> RF..noise.
>
> How anyone can epect to filter RFI out of the line without removing the
> broadband, beats me.

By using a "Common Mode Choke" - that's how. Look it up. Loads of
references.
-----------------------------------------------------------------------
OK - now to assist the OP -

The wanted ADSL signal is in Differential Mode (equal and opposite
polarities on the A and B wires of the pair). The signal circuit is the
loop from exchange, out through the customer's router/modem, and back to
the exchange.

The unwanted signal will be in Common Mode. That is - the A and B wires
will have the SAME polarity and direction of signal on each. The circuit
formed, through which the interference will flow, will be via signals
induced on BOTH wires equally, through the customer's equipment (causing
the problems !), and to earth via stray capacitive coupling.

A common mode RFI choke on the cable between the router and the line
socket will probably fix this problem, by breaking the Common-Mode
circuit, whilst leaving the differential mode circuit unaffected. A
clip-on ferrite core will work, but only with multiple turns of wire
through it. It's effectiveness at low HF (3.5MHz) is proportional to the
square of the number of turns.
How to do this - open the clip-on core, wind as many turns of the cable
over one half of the core as you can and still be able to clip the core
shut. Job done.

I use this remedy myself. It completely removed local RF interference.
It had NO EFFECT WHATEVER on the ADSL signal - sync rates and SNR are
unaffected.

Glenn Myers wrote:
> "The Natural Philosopher" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Kráftéé wrote:
>>> Glenn Myers wrote:
>>>> Does anyone think that clip on ferrite cores might help reducing RFI
>>>> from a phone line? I know I should just try it, but wondered if
>>>> anyone had already stopped RF interference using them? The
>>>> interference is being caused by a local radio ham, who I am on good
>>>> terms with and who has offered to help cure the problem.
>>> First thing to try would be a RF filter on the line or even a plugin
>>> RF filter. Be aware that the usage of such things could affect your
>>> broadband if used incorrectly just as using any of the tried & tested
>>> solutions from the 'Hams' arsenal could do.
>>>
>>>
>> Mot of the intereference on long broadband lines IS RF ..Broadband IS
>> RF..noise.
>>
>> How anyone can epect to filter RFI out of the line without removing the
>> broadband, beats me.
>>
>> What band is the ham on?
>
>
> 3500 KHz
>
>
You are fucked then.

It only take the tiniest bit of nonlinearity in your outside cabling..a
weeny bit of corrosion, or simply a metal to metal joint to mix that
down to the broadband frequencies.

For the purposes of broadband, the line to the exchange is 'inside the
house'




>

Blah Blah Blah wrote:
> On Sun, 01 Feb 2009 12:51:35 +0000, Krft faxed us with....
>
>> Glenn Myers wrote:
>>> Does anyone think that clip on ferrite cores might help reducing RFI
>>> from a phone line? I know I should just try it, but wondered if anyone
>>> had already stopped RF interference using them? The interference is
>>> being caused by a local radio ham, who I am on good terms with and who
>>> has offered to help cure the problem.
>> First thing to try would be a RF filter on the line or even a plugin RF
>> filter. Be aware that the usage of such things could affect your
>> broadband if used incorrectly just as using any of the tried & tested
>> solutions from the 'Hams' arsenal could do.
>
> And broadband does not operate up to the lower end of RF spectrum at all
> then? Mmmm. You are starting to scare me.
>
Upstream is about 30Khz-120Khz, downstream 150Khz-1.1Mhz but the main
energy is sub 600Khz.

Its clear of the SW bands, but not by much.