Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Pages: [1] 2 3 ... 5

Author Topic: ADSL Surge Protector - a cautionary tale  (Read 36061 times)

hake

  • Reg Member
  • ***
  • Posts: 296
  • Owzat! On ya way, back to the pavilion!
ADSL Surge Protector - a cautionary tale
« on: May 14, 2009, 10:18:40 AM »

Much learned thought has been expended for my benefit in the past few days.  I had a presumed problem with upstream performance.  The advice offered and acted on has been of great benefit.  The effect of the advice was to route the the ADSL cable away from mains electricity and to use passive microfilters on the low pass telephone cable plant.

However, the problem of reduced upstream speed and a puzzlingly low upstream SNRM remained.

It is with much embarrassment that I now present the reason for the upstream problem (and to a lesser degree the downstream also).
I had put an ADSL Surge Protector in line with the ADSL cable.   :-[

I had become blind to the presence of the surge protector (obviously a cheap and exceedingly nasty device).

I mention this so that others might avoid my self-induced predicament.

I must thank to all those who gave their time to my 'problem'.  I have, nonetheless, benefited from their expertise as the router's performance stats show:-

Rx: 4704kbps     SNRM 16db
Tx:   448kbps     SNRM 16db

Oh, I'm so ashamed.    :-[

« Last Edit: May 14, 2009, 10:23:23 AM by hake »
Logged
Windows XP

roseway

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 43467
  • Penguins CAN fly
    • DSLstats
Re: ADSL Surge Protector - a cautionary tale
« Reply #1 on: May 14, 2009, 10:26:20 AM »

No need to be ashamed. You ought to be able to rely on a surge protector.

It really does look as though you've traced the problem, so that's great news. :thumbs:
Logged
  Eric

sevenlayermuddle

  • Helpful
  • Addicted Kitizen
  • *
  • Posts: 5369
Re: ADSL Surge Protector - a cautionary tale
« Reply #2 on: May 14, 2009, 10:44:48 AM »

Thanks for the feedback Hake, that's great news.   :thumbs:

With any luck your downstream sync-speed will increase further over the next few weeks or months, as DLM allows the SNR margin to relax.

And following a few days behind each improvement in sync-speed, your IP Profile will be also be raised leading to faster actual download speed.

You now have a line that many of us would be envious of  :)
Logged

hake

  • Reg Member
  • ***
  • Posts: 296
  • Owzat! On ya way, back to the pavilion!
Re: ADSL Surge Protector - a cautionary tale
« Reply #3 on: May 14, 2009, 10:46:56 AM »

I have you guys to thank.  I found the offending item (now binned) on eBay.  Where do I find a good ADSL surge protector?
Logged
Windows XP

jid

  • Content Team
  • Kitizen
  • *
  • Posts: 1945
Re: ADSL Surge Protector - a cautionary tale
« Reply #4 on: May 14, 2009, 05:00:15 PM »

I use this:-
http://www.argos.co.uk/static/Product/partNumber/9822980/Trail/searchtext%3EMASTERPLUG+SURGE.htm

Not the cheapest but doesn't affect the ADSL. I connected through it a while back and didn't seem to cause any problems at all.
Logged
Kind Regards
Jamie

BT FTTP - 75meg | Sky Q |  Bridgend Weather

hake

  • Reg Member
  • ***
  • Posts: 296
  • Owzat! On ya way, back to the pavilion!
Re: ADSL Surge Protector - a cautionary tale
« Reply #5 on: May 14, 2009, 05:05:12 PM »

Thanks jid.  I will look into that.
Logged
Windows XP

westom

  • Member
  • **
  • Posts: 21
Re: ADSL Surge Protector - a cautionary tale
« Reply #6 on: May 14, 2009, 09:29:29 PM »

Where do I find a good ADSL surge protector?
  First, ADSL is a radio wave.  Any high capacitance protector will degrade DSL 'radio' signals (for the same reason that conventional telephones eat DSL and need that blocking filter.)   A DSL protector must be low capacitance to not 'eat' radio signals.
  Second, the protector is not protection.  Protectors do not stop or absorb surges.  Effective protectors connect surge energy to the protection - a separate device.  Protection is earth ground.  To provide protection, a protector must connect short (ie 'less than 3 meter) from each phone wire to earth.  This has been routine in every telco CO everywhere in the world for the past 100 years.  To make a protector even better, a lower capacitance protector is connected even shorter to earth.  Every meter shorter increases protection.

  Third, distance between a protector and ADSL hardware increases protection.  Wire has low resistance but higher impedance.  Wire impedance is why wire length is relevant.  An even shorter distance to earth means a better connection from telephone wire to earth ground - lower impedance (not to be confused with characteristic impedance).  Increased separation between the DSL modem and protector means higher impedance.  More surge harmlessly absorbed in earth when a protector is connected shorter from phone wire to earth.  Less surge will find earth ground destructively via your ADSL hardware.

  Important is how that wire connects to earth.  For example, sharp wire bends, wire bundled with non grounding wires, inside metallic conduit, using a different earthing electrode from AC electric and cable, wire splices ... all adversely increase impedance to ground - decrease protection.

  Better DSL protectors use semiconductor devices such as Sidactor or low capacitance avalanche diodes (such as   http://www.semtech.com/pc/downloadDocument.do?id=532).  At the consumer level, the protector must specifically state in numeric specs that it is rated for DSL operation.  And, of course, it must have a dedicated connection to earth.  Protectors do not stop or absorb surges.  Protectors simply divert surge energy harmlessly in earth - and remain functional even after a direct lightning strike.  You will be amazed little a protector need be when it diverts (does not absorb) energy even from direct lighting strikes.

  Meanwhile it must also be low capacitance so that it appears non-existent to ADSL signals (radio waves).
Logged

orainsear

  • Reg Member
  • ***
  • Posts: 635
Re: ADSL Surge Protector - a cautionary tale
« Reply #7 on: May 14, 2009, 10:29:15 PM »

Is there any particular reason that you need a surge protection device on your line - do you have an expensive modem?  As has been mentioned proper protection involves bonding to earth, which can be easier said than done.
Logged

sevenlayermuddle

  • Helpful
  • Addicted Kitizen
  • *
  • Posts: 5369
Re: ADSL Surge Protector - a cautionary tale
« Reply #8 on: May 14, 2009, 11:43:20 PM »

Is there any particular reason that you need a surge protection device on your line - do you have an expensive modem?  As has been mentioned proper protection involves bonding to earth, which can be easier said than done.

You might also want to consider the fact that the master socket already contains a surge protector, and the router will almost certainly have one too.  These won't save your router from a direct lightening strike on your house, but if that happens a charred router would probably be the least of your worries.
Logged

westom

  • Member
  • **
  • Posts: 21
Re: ADSL Surge Protector - a cautionary tale
« Reply #9 on: May 15, 2009, 08:05:07 AM »

You might also want to consider the fact that the master socket already contains a surge protector, and the router will almost certainly have one too.  These won't save your router from a direct lightening strike on your house, but if that happens a charred router would probably be the least of your worries.
  Surge protectors are earthed so that direct lightning strikes do not even damage the protector.  Protectors that don't provide lightning protection are only protecting profit margins.

  BT has switching computers connected to wires all over town.  With every thunderstorm, the typical CO suffers 100 surges.  How often has phone service in your town been lost for four days while they replace that switching computer?  Earth protectors are that effective and that routine.

  So that lightning is harmless even to the protector, every incoming wire is earthed by a 'whole house' type protector.  Energy diverted to and absorbed harmlessly by earth does not enter the building; does not cause damage.

  All appliances contain surge protection.  Even required by international standards.   A protector cannot divert energy harmlessly into earth without that earthing connection.  A protector without earthing protects only from a type of surge that is typically not destructive.  Install and earth a 'whole house' protector so that the rare and so destructive surge does not overwhelm existing internal appliance protection.

To answer orainsear's question: these destructive surges occur typically once every seven years.  Less frequently in the UK.  But frequency varies significantly even within a town.  Install and earth a 'whole protector so that a rare and destructive surge does not damage protection already inside every appliance.
Logged

hake

  • Reg Member
  • ***
  • Posts: 296
  • Owzat! On ya way, back to the pavilion!
Re: ADSL Surge Protector - a cautionary tale
« Reply #10 on: May 15, 2009, 08:05:50 AM »

Thank you for those thoughts.  I have decided not to use additional inline surge protection.  I have, however, dug up an inline ethernet surge protector which now sits between the router and an ethernet switch.  It uses a mains ground.  The ADSL signal should not be impaired by this arrangement.
« Last Edit: May 15, 2009, 08:40:22 AM by hake »
Logged
Windows XP

orainsear

  • Reg Member
  • ***
  • Posts: 635
Re: ADSL Surge Protector - a cautionary tale
« Reply #11 on: May 15, 2009, 08:34:57 AM »

To answer orainsear's question

Thanks for the reply but I was actually asking hake about his needs for a surge protector device in his setup   :D
Logged

westom

  • Member
  • **
  • Posts: 21
Re: ADSL Surge Protector - a cautionary tale
« Reply #12 on: May 15, 2009, 08:45:01 AM »

 I have, however, dug up an inline ethernet surge protector which now sits between the router and an ethernet switch.  

 An inline protector means nothing sits in that wire. For example, are these your protector?
http://www.keison.co.uk/furse/furse19.htm
http://www.tripplite.com/en/products/model.cfm?txtModelID=151

  See that ground wire?  If not connected to earth, then no protection exists.  The ethernet wire goes right through the magic box - nothing but wire.  A protector connects from each wire to that ground wire.  If that ground wire is not connected short to earth, the protector does nothing.  What can it do?  One side is connected to nothing.  No earth ground means no place for electricity to flow.

  Does a magic box provides protection? None do.  The magic box does nothing if not connected to protection.  A ‘magic box’ is only a connecting device - to connect a surge to protection.  No earth ground means a protector does nothing.

Ethernet protectors typically are rated for voltages that are below phone line voltages. Phone line protectors are typically 300+ volts.  Ethernet wire protectors typically are only tens of volts.  The ethernet protector may regard a ringing phone as a surge.   But since the protector circuit is not connected to earth, then it does nothing for surges AND hopefully does nothing to impeded telephone operation.

  Just because it is a magic box called a surge protector, then you think it does something?  Some protector too close to appliances can even make surge damage easier.
« Last Edit: May 15, 2009, 09:18:05 AM by westom »
Logged

hake

  • Reg Member
  • ***
  • Posts: 296
  • Owzat! On ya way, back to the pavilion!
Re: ADSL Surge Protector - a cautionary tale
« Reply #13 on: May 15, 2009, 09:31:37 AM »

Yes, I see.  Just like the safety valves on a steam locomotive's boiler, there has to be path for the unwanted energy to be channelled through.

That means that the cheap and nasty inline surge protector device I wasted my money on could not have been effective.  How easily are the gullible parted from their money.

The ethernet surge protection I am now using can presumably dump the surge energy to mains earth (when plugged in).  It's a shame that such devices fail a PAT test.
« Last Edit: May 15, 2009, 09:36:07 AM by hake »
Logged
Windows XP

sevenlayermuddle

  • Helpful
  • Addicted Kitizen
  • *
  • Posts: 5369
Re: ADSL Surge Protector - a cautionary tale
« Reply #14 on: May 15, 2009, 09:51:16 AM »

Hake,

I don't want to worry you (indeed, I've already confessed that I don't worry about it at all really), but whilst I'm sure putting protection on the ethernet cable does no harm, even if its is earthed I fear it is necessarily as it good as it might appear....

...I'm thinking that an incoming spike on the phone wire could find a path, via the router and its PSU, to the live or neutral mains conductors. From there, it would look for a path to ground which might be straight through your TV, computer, Hi Fi - or all of them.   :'(

But I freely admit I'm no expert and hopefully somebody will put me right if they no better  :)

getting back to Orainseer's question... do you feel that you're particularly at risk?
Logged
Pages: [1] 2 3 ... 5