Message-ID: <5da801cb8faa$ea2e0d50$7900a8c0@athlon1200>
From: "Dave Brown" <tractorb@ihug.co.nz>
To: <rsgb_lf_group@blacksheep.org>
References: <439635.1425.qm@web28101.mail.ukl.yahoo.com> <25671BC19A084642B38CBC31639E7633@lindavideo>
Date: Mon, 29 Nov 2010 22:50:54 +1300
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Subject: Re: LF: Any  ADSL2  BBand router / RF proof ?
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A large common mode choke on the incoming line, just down stream 
towards the modem from the ETP (=NTE over there I guess) and again at 
the input to the modem did it for me. Using a single ADSL filter at 
the ETP and connecting the modem at that point, as opposed to the DIY 
'filter per CPE outlet ' setup with the modem fed from a unknown 
configuration of extension wiring, will give better performance as 
well.
73
 Dave, ZL3FJ


----- Original Message ----- 
From: "Ken" <ken.h.wright@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Monday, November 29, 2010 9:13 AM
Subject: Re: LF: Any ADSL2 BBand router / RF proof ?


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
  To: rsgb_lf_group@blacksheep.org
  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 <g8fzk@g8fzk.fsnet.co.uk> wrote:


          From: Graham <g8fzk@g8fzk.fsnet.co.uk>
          Subject: Re: LF: Any ADSL2 BBand router / RF proof ?
          To: rsgb_lf_group@blacksheep.org
          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
          To: rsgb_lf_group@blacksheep.org
          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 
<g8fzk@g8fzk.fsnet.co.uk> wrote:


                        From: Graham <g8fzk@g8fzk.fsnet.co.uk>
                        Subject: LF: Any ADSL2 BBand router / RF proof 
?
                        To: rsgb_lf_group@blacksheep.org
                        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..