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Re: LF: Any ADSL2 BBand router / RF proof ?

To: [email protected]
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?
From: M0FMT <[email protected]>
Date: Mon, 29 Nov 2010 00:44:40 +0000 (GMT)
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Hi Ken
 
Thanks for the "teach in". Tell me why is BT so keen on copper wire it has nothing but disadvantage.Open Reach must spend millions of pounds trying to make it work. And now with these raids on the ducting because of the value of copper it make even more sense to change over to fibre. However I am being told it will never happen because on lack of expertise within BT. These comments come from Open Reach at Liverpool. Have you any idea why they don't import some engineering talent? 
73 petefmt

I support www.NotSpotTelecom.Com your community Telco / ISP.

--- On Sun, 28/11/10, Ken <[email protected]> wrote:

From: Ken <[email protected]>
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?
To: [email protected]
Date: Sunday, 28 November, 2010, 20:13

Hello Everyone.
I think you will find that with your line length from the serving exchange  (7km)?  the S/N ratio will be poor, a minimum of 10dB is required, my copper connection is about 2.7km which is considered to be approaching the limit, although the tests at the customer NTE showed that 3Mbt/s.should have been possible. At these line lengths any rf will swamp the DSL signal. I have discussed this problem at length several time with the people I worked with at Adastral Park ( commonly known as BT Labs), both DSL and EMC, the problem is compounded if a) you have a long length of overhead drop wire, b) the number and configuration of any internal extensions, and c) the position of the router with respect to the incomming NTE (master socket). If the dropwire is long, the induced common mode interference will be transformed into differential mode before it reaches the router, any internal extension wiring will increase attenuation, especially if it is a 'star configuration.
The router should be as close as possible to the incoming NTE. A spectral analysis of my line revealed that there were no DSL carriers above 500kHz, hence not being able to use 500kHz, if the router shuts down because a corrupted incoming signal, it will start a 're-training' sequence with the DSLAM in the serving exchange, however if either the line or the router is changed, the exchange equipment will then go though a process of determining the best possible data speed of the new configuration, thia can take up to ten days, if during this time any of the speedtest sites are used different data rates will be loged.
 
I changed my 1st generation BT Homehub router for an older BT Voyager 2500,  which improved the situation with the HF bands but not at 500kHz, even with high value common mode chokes on everything in sight. The problem was finally solved by changing over to BT Infinity Fibre To The Cabinet (FTTC) with copper line length of 400m giving data speeds of 14Mbt/s.
 
I hope some of this is both of use and interest you all.
 
73
Ken
M0KHW    
----- Original Message -----
From: M0FMT
Sent: Friday, November 26, 2010 10:08 AM
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?

Hi Again Graham and LF
 
Hmmmmm OK looks like you are in better shape than me. A local station who has difficulty with his ADSL has put Ferrite clamp on filters on all leads in and out of the Modem including the power supply lead. He claims (and I have no reason to doubt him) that this has solved his problems. The modem is the new BT Black Box one. I have one of those although much more reliable and faster it still suffers from my description below. The issue I have appears not to be Modem related but exchange based.
 
I talk to Larry regularly on 4m so next time, if I remember, I will get the details of his solution Viz ferrite type and where on the lines he is fitting them and forward it to you. It may help.
As before good luck with your efforts; what ever success you get please publish it. Ken M0KHW Luton has an ADSL problem too so several people would be interested I am sure.

73 es GL petefmt

I support www.NotSpotTelecom.Com your community Telco / ISP.

--- On Fri, 26/11/10, Graham <[email protected]> wrote:

From: Graham <[email protected]>
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?
To: [email protected]
Date: Friday, 26 November, 2010, 0:49

Ok Pete
 
This is the new  router , as its  in the  same place as the old one , with (now) the  same  filters , the  PC is  linked with a  short network  cable , the  rest of the  pc's are  linked by radio. its the  adsl  like thats  failing
 
The edimax   router was  quite  robust , never had a drop  out on HF and only  over 200  watts  , feed , on 500  would stop  the  link , this one  fails  with  25  watts  on 160  .. the  router  is  off  most of the  day  and  night  , only  on  with the  pc , the  new  router  is faster  , from 6 (old)  meg to 9 med  down  and  500k (old) to  890 k upload , but  if it  keeps  dropping  out  with no  cure then  its not  much  use for  my usage
 
G,

From: M0FMT
Sent: Friday, November 26, 2010 12:26 AM
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?

Hi Graham
 
Are you sure the problem is the router?
 
136, 500, 160 and to some extent 80m here are kill the ADSL. Even at very low powers. If your ADSL is cut during your transmissions only and resumes at the original speed directly afterwards it may well be the router being temporarily being knocked out. If however you line stays down for a period of time say several hours then it is not the router. What you are doing is putting noise (owing to RF) onto your line which is being picked up at the exchange DSLAM. The exchange equipment (DSLAM) serving your line will reduce data speed to ensure that a connection of sorts is maintained. This speed can go down to below 80kb/s from which it will not recover without technical intervention by BT Open Reach. If it goes down to about 300/500kb/s it may well recover it's original speed over a period of time BT quote 72 hours yes 72 hours (I think this time period is not a technical issue but one to stall the punters off). On a good day the recovery period can be speeded up by turning the router off and disconnecting every thing from the line and waiting. This makes a quiet line for the automatic recovery to work.... on a good day!!! If you don't have enough life left to wait for BT to physically do some thing then the best thing is to write to BT HQ in London to the their CEO (his name and location can be found with a bit of research) and tell him what you think of his outfit. I know from experience he does not like receiving this kind of letter. You may have your ISP as Joe Blogs Internet Provider dot Com but in reality it is all provided by BT they own the final mile and the exchange ...... legal niceties to one side it is a fact.
If you get a good Broad Band data rate of say 4/8mb/s your transmissions on LF/MF will only slightly degrade your ADSL but if like me on the end of 7.5km of copper its only 1/1.5mb/s on a very good day, RF will wipe out your ADSL for a week or more. So without a lot of letter writing to BT and angry phone calls your ASDL will not return to original speed..
 
To maintain a usable data rate on Broad Band here I can not use 136 or 500kc/s above a few Milli Watts at TX output about 1 Watt on 160m 80 about 50Watts and on 60m and above 100Watts (possibly more but not tested yet). Also the longer you stay on the worst the speed degrades.My guess is with ADSL2 having a much wider bandwidth the problem for Amateurs will extend further up the spectrum than shown above.
 
Hope you are not in my situation....... Oh and don't believe all this Fibre stuff. Open Reach have told me that one reason why Fibre is not being rolled out like the Virgin setup is that there are only a few BT people capable of working with Fibre. This is the reason why BT is Wedded to copper wire. So we locally have Internet breakdowns owing to Junkies and the like ripping the Copper cables out of BT ducting to pay for drugs... Bedfordshire has had Internet disconnections for days owing to this phenomenon. So along with cable theft and the lack of trained staff a proper interference free Broad Band coverage using fibre in this country is looking particularly bleak.
 
Good luck!

73 es GL petefmt

I support www.NotSpotTelecom.Com your community Telco / ISP.

--- On Thu, 25/11/10, Graham <[email protected]> wrote:

From: Graham <[email protected]>
Subject: LF: Any ADSL2 BBand router / RF proof ?
To: [email protected]
Date: Thursday, 25 November, 2010, 22:06

Any  ADSL2  BBand router / RF proof ?
 
Just upgraded to  ADSL2  with a  orange  net-gear   router/wifi  router, now   15  watts  on  160  kills  the  connection 
 
router is in the  same location as  the old  edimax , which  kept running  with  200 watts  on 500 K  and  400 on Hf
 
? any  RF proof  ADSL2  on the  market >
 
Tnx - G.. 







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