Kitz Forum
Broadband Related => Telephony Wiring + Equipment => Topic started by: Weaver on August 16, 2015, 04:55:34 PM
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I have already made all these changes for my ultra-long lines (ADSL1). Some of these items will not necessarily help _you_ as you may have no problem to fix or a much stronger signal, but they won't hurt.
the list, in no particular order
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* Ferrites on dc power cables (might do nothing at all)
* RJ-11 cable, best quality, v short - Tandy / adslnation
* Mains cables away from other cables
* Mains filtering and conditioning (esp. if using a UPS)
* Good faceplate microfilter aka SSFP, no danglies
* Correct faceplate filter choice for service type, maybe avoid BT Mk3
* No extensions, or no phones
* If you absolutely must have extensions, make sure they are prefiltered in the faceplate
* Don't put the modem on an extension! Rather, move the router if a separate unit or better still move the NTE5
* Modem change?
* NTE5 placement, and length of internal BT Openreach wiring
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Explanations / elaborations will follow in this thread.
This will save me from repeating the same advice again and again.
I can't pretend that every item has been subject to proper scientific testing, but most of the items are very low-cost changes.
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I would cross ferrites off the list, unless you really understand their technical characteristics. There are numerous different ferrite materials, with differing characteristics, and they need to be specified for the particular requirement. If you just pick one from a catalogue, the most likely outcome is that it will do nothing, otherwise it's just as likely to make things worse as to make things better.
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@roseway - ferrites on dc cable?
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Perhaps you could help with split ring ferrite spec, as a < 50Hz low-pass filter is all that's required.
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I'm afraid I don't have the expertise. I was just making the point that ferrites are not any sort of panacea, and they need to be selected appropriately for the job. Just fitting any convenient split-ring ferrite over the cable is not likely to achieve anything significant.
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@ I completely agree with you about the ferrites, might well do nothing at all as there's no problem to fix besides the spec issue you mentioned.
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I'm afraid I don't have the expertise. I was just making the point that ferrites are not any sort of panacea, and they need to be selected appropriately for the job. Just fitting any convenient split-ring ferrite over the cable is not likely to achieve anything significant.
If the aim is to attenuate pickup on a cable they can be very iffy, since as there is a standing wave their effect will be position - and wavelength dependent !
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@jgo - No, not trying to attenuate pickup. Just trying to drop noise coming out of PSU itself or from a nasty UPS.
Warning, Weaver is hopeless on electronics yet holds a degree in Theoretical Physics, a toxic brew of ignorance. ;D ;D ;D :'(
I placed my ferrites at both ends of the dc cable, as close to the ends as I could.
As for interference pickup, perhaps there's something intelligent that could be done with bundling or wrapping the cable up so as to minimise its ability to act as an effective aerial?