Kitz Forum

Broadband Related => Telephony Wiring + Equipment => Topic started by: neil on August 07, 2020, 07:46:37 PM

Title: DIY filter for REIN and RF noise
Post by: neil on August 07, 2020, 07:46:37 PM
Can someone please help me build filter for REIN and RF noise?
or identify components used here for REIN and RF filtering in this vdsl faceplate?
Title: Re: DIY filter for REIN and RF noise
Post by: neil on August 07, 2020, 07:47:23 PM
if possible pleas post link from ali epxress of the components
Title: Re: DIY filter for REIN and RF noise
Post by: neil on August 07, 2020, 08:31:44 PM
ferrite core or toroidal ring is used for RF filtering?
Title: Re: DIY filter for REIN and RF noise
Post by: Alex Atkin UK on August 07, 2020, 10:03:36 PM
Wouldn't filtering one end of the line create an imbalance?  The interference will still exist but your end might not see it, while its still corrupting the DSL signal at the other end?
Title: Re: DIY filter for REIN and RF noise
Post by: neil on August 07, 2020, 11:44:39 PM
Wouldn't filtering one end of the line create an imbalance?  The interference will still exist but your end might not see it, while its still corrupting the DSL signal at the other end?
hmm i dont know thats why i am asking here
Title: Re: DIY filter for REIN and RF noise
Post by: Alex Atkin UK on August 08, 2020, 03:11:20 AM
hmm i dont know thats why i am asking here

Fair enough.  But several regulars (I believe even the site owner) suffers REIN, so if it was THAT easy, someone would have done it.  ;)
Title: Re: DIY filter for REIN and RF noise
Post by: mrk26 on August 09, 2020, 11:31:46 AM
Can someone please help me build filter for REIN and RF noise?
or identify components used here for REIN and RF filtering in this vdsl faceplate?
Did you tried this https://www.bcedirect.co.uk/products/broadband-stabiliser-and-line-conditioner-faster-more-reliable-broadband-increase-broadband-speed-lower-broadband-dropouts (https://www.bcedirect.co.uk/products/broadband-stabiliser-and-line-conditioner-faster-more-reliable-broadband-increase-broadband-speed-lower-broadband-dropouts) looks like it's something you try to build?
Title: Re: DIY filter for REIN and RF noise
Post by: Alex Atkin UK on August 09, 2020, 10:01:47 PM
Did you tried this https://www.bcedirect.co.uk/products/broadband-stabiliser-and-line-conditioner-faster-more-reliable-broadband-increase-broadband-speed-lower-broadband-dropouts (https://www.bcedirect.co.uk/products/broadband-stabiliser-and-line-conditioner-faster-more-reliable-broadband-increase-broadband-speed-lower-broadband-dropouts) looks like it's something you try to build?

Seems to be a capacitor and an inductor.  Despite what they say I'm pretty sure there is nothing here that isn't already in a good line filter, its just the filter has additional electronics to isolate the voice frequencies too.
Title: Re: DIY filter for REIN and RF noise
Post by: neil on November 25, 2020, 09:16:17 PM
according to this video
https://youtu.be/jD67a-ZC7VY?t=450

@ 7:30

presumably this toroid core is the rein filter
now only if we knew the specs  ???

Title: Re: DIY filter for REIN and RF noise
Post by: neil on November 25, 2020, 10:13:32 PM
https://www.youtube.com/watch?v=J6ZKPT67JA0

where is the full video  :no:
Title: Re: DIY filter for REIN and RF noise
Post by: Weaver on November 26, 2020, 05:58:29 AM
Good micro filters / SSFPs have complex electronics to handle the on/off hook condition too.
Title: Re: DIY filter for REIN and RF noise
Post by: burakkucat on November 26, 2020, 04:51:16 PM
presumably this toroid core is the rein filter

It is a common-mode filter.

An xDSL service exists between two analogue transceiver units, the xTU-C and the xTU-R, connected together by a radio frequency transmission line consisting of a pair of twisted wires carried within one or more sequentially connected cables. The analogue transceivers operate in differential mode. Think of one moment in time (if you like, consider the circuit "to be frozen" in time) and we look at the state of the circuit. The circuit consists of two wires, one twisted pair (with wires labelled A & B), and at that "frozen" moment in time let's say that the the electrons in the wire labelled A are "pushing" from the xTU-C to the xTU-R whilst the electrons in the wire labelled B are "pushing" from the xTU-C to the xTU-R. That is differential mode operation. Now consider the cable carrying the twisted pair of wires linking the xTU-C to the xTU-R. In a real world situation that cable has significant length and can pass through regions where there are (legitimate) high strength RF signals, pulsed electromagnetic-fields, switched high-current inductive loads (to name three possible sources of interference to the xDSL service.) As the xDSL service is carried over a twisted pair, whatever interference that is coupled into the A-wire of the pair is also coupled into the B-wire of the pair. The interference, therefore, appears in common-mode on the pair. Hence the usage of that common-mode filter. It rejects any common-mode signal on the pair whilst allowing the differential-mode signal on the pair to pass unhindered.
Title: Re: DIY filter for REIN and RF noise
Post by: burakkucat on November 26, 2020, 04:53:19 PM
https://www.youtube.com/watch?v=J6ZKPT67JA0

where is the full video  :no:

Openreach have removed numerous videos from its YouTube channel and, I presume, that video was one so removed.  :(
Title: Re: DIY filter for REIN and RF noise
Post by: neil on November 26, 2020, 07:49:24 PM
It is a common-mode filter.

An xDSL service exists between two analogue transceiver units, the xTU-C and the xTU-R, connected together by a radio frequency transmission line consisting of a pair of twisted wires carried within one or more sequentially connected cables. The analogue transceivers operate in differential mode. Think of one moment in time (if you like, consider the circuit "to be frozen" in time) and we look at the state of the circuit. The circuit consists of two wires, one twisted pair (with wires labelled A & B), and at that "frozen" moment in time let's say that the the electrons in the wire labelled A are "pushing" from the xTU-C to the xTU-R whilst the electrons in the wire labelled B are "pushing" from the xTU-C to the xTU-R. That is differential mode operation. Now consider the cable carrying the twisted pair of wires linking the xTU-C to the xTU-R. In a real world situation that cable has significant length and can pass through regions where there are (legitimate) high strength RF signals, pulsed electromagnetic-fields, switched high-current inductive loads (to name three possible sources of interference to the xDSL service.) As the xDSL service is carried over a twisted pair, whatever interference that is coupled into the A-wire of the pair is also coupled into the B-wire of the pair. The interference, therefore, appears in common-mode on the pair. Hence the usage of that common-mode filter. It rejects any common-mode signal on the pair whilst allowing the differential-mode signal on the pair to pass unhindered.

and how's the graph or plot looks like with and without this common mode filter?
noise level etc
Title: Re: DIY filter for REIN and RF noise
Post by: 4candles on November 26, 2020, 08:03:02 PM
An excellent exposition from burakkucat.   :graduate:  (https://forum.kitz.co.uk/index.php?action=profile;u=3667)
Title: Re: DIY filter for REIN and RF noise
Post by: burakkucat on November 26, 2020, 09:55:01 PM
and how's the graph or plot looks like with and without this common mode filter?
noise level etc

I have never performed such an experiment, as it would be very difficult for me to simulate legitimate RF signals, inductive load switching and various pulsed e/m-fields.

My earlier post is a theoretical description of the operation of a common-mode filter within a circuit troubled by external interference. Against the positive aspects, described above, there is also a negative aspect . . . by inserting the filter into the circuit, the wanted (differential-mode signal) is also slightly attenuated. In other words the common-mode filter is responsible for a small, but measurable, insertion loss. With an essentially perfect xDSL circuit, i.e. one that is free from any of the troubles that a common-mode filter could mitigate, fitting such a filter will attenuate the wanted differential-mode signal (by virtue of the intrinsic insertion loss) with no obvious gains. So fitting a common-mode filter is not necessarily a "win" for every xDSL circuit.
Title: Re: DIY filter for REIN and RF noise
Post by: Weaver on November 27, 2020, 01:32:29 AM
Agrees with Burakucat. You have on the A wire, voltage: A+interference, and on the B wire: B+interference; then the receiving unit subtracts the one from the other, giving: (A+interference) - (B+interference) = A+interference - B-interference = A - B : which is just the signal alone, ideally
Title: Re: DIY filter for REIN and RF noise
Post by: neil on November 28, 2020, 11:41:16 AM
It is a common-mode filter.

An xDSL service exists between two analogue transceiver units, the xTU-C and the xTU-R, connected together by a radio frequency transmission line consisting of a pair of twisted wires carried within one or more sequentially connected cables. The analogue transceivers operate in differential mode. Think of one moment in time (if you like, consider the circuit "to be frozen" in time) and we look at the state of the circuit. The circuit consists of two wires, one twisted pair (with wires labelled A & B), and at that "frozen" moment in time let's say that the the electrons in the wire labelled A are "pushing" from the xTU-C to the xTU-R whilst the electrons in the wire labelled B are "pushing" from the xTU-C to the xTU-R. That is differential mode operation. Now consider the cable carrying the twisted pair of wires linking the xTU-C to the xTU-R. In a real world situation that cable has significant length and can pass through regions where there are (legitimate) high strength RF signals, pulsed electromagnetic-fields, switched high-current inductive loads (to name three possible sources of interference to the xDSL service.) As the xDSL service is carried over a twisted pair, whatever interference that is coupled into the A-wire of the pair is also coupled into the B-wire of the pair. The interference, therefore, appears in common-mode on the pair. Hence the usage of that common-mode filter. It rejects any common-mode signal on the pair whilst allowing the differential-mode signal on the pair to pass unhindered.
thank you 🤗