[RFI] 4khz Spectrum comb ADSL2 one last try composed as text

[w2ttt at att.net]

Hmmm...we'll it is m interesting that Clink had the approach to increase subcarrier power in the face of interference.  That approach is not what I've seen in other DSL systems.  Glad to see that they don't do that anymore, but doing nothing seems equally inefficient. 


As for loose cables...they may not be connected at the other end - HOPEFULLY!

They are left in place because there are costs related to sending out a tech, so if there is no positive determination of harm, they get left in place.


73,

Gordon, W2TTT 

201.314.6964





Get Outlook for Android









On Thu, Mar 2, 2017 at 4:47 PM -0500, "HankP" <pfizenmayer at q.com> wrote:










HI Gordon -- I have read about the   4.3125 standard spacing  - This Clink system is within a hz of  4 khz,    for instance 7007.783 , 7011.783 .. There now happens to be another set also spaced exactly 4 khz - but offset by about 44 hz. I was not seeing that before the new cable. 

Why Clink is not using an "industry standard" I have no idea.  It might be because AT&T owned these lines circa 1970s - started carrying Uverse  - which I had - then Qwest bought the frranchise from ATT and dropped the Uverse and we went to DirecTV . Now Clink is pushing their "Prism" TV 

So the basic plant may be from some time ago . I am still using the same modem I started with with AT&T , Clink limits me to 20 mbps internet because of that modem but it does all we need. .

When this mess started a little  over a year ago  , at first there would be periods of no carriers at all. Then if I transmitted on160 with even 1 watt !!!! carriers would start appearing and the longer I transmitted - more carriers would appear . At 1500 watts , carriers would appear as a full comb from somewhere just above 1700 khz to about 2100 khz . After a month or so the carriers would be there all the time maybe not a full comb but then it would  add carriers as I transmitted and the longer I transmitted or at higher power - the system would raise the level of the carriers . I have EXCEL spread sheets of the early  progression - its almost funny . 

I dont see that behavior anymore - carriers always there and very little increase in max carrier levels as I transmit . 

But the bottom line still remains - why I seem to be the only guy in the world seeing this is beyond me. I certainly am not in a noise free environment - buried in a sea of other noise. 

With regard to getting Clink to do anything - that is a whole different problem. And what I presented was only the tip of the iceberg in interacting with Clink and their tech. (not the Ham - but the ham  was called in because the first tech said "he could not talk to me " . What he really means is  he has absolutely zero RF knowledge and refused to even look at my data or listen to the carriers . ( He is the "expert" on ADSL/VDSL , teaches the courses to other techs )  He informed me about 5 minutes after arriving that this was not his first  Rodeo and at the end of the frst day after about 6 hours of twiddling with the pairs from the DSLAM to my house with zero effect refused to give me a contact number or his employee number or even his name - and "johnny" was all I needed to know. He even threatened to turn me into the FCC as I was interfering with their system !!!!!!!! I will admit I did  retort - that would be great - please do. The ONLY number I have with Clink is thru the Engineer in Denver. (And if I am to believe the Denver guy - (which I do because he has worked with W0IVJ) it took him about 3 weeks to even find a contact for him to get anyone out here in Phoenix. (And even though the Denver Engineer  had identified the exact source customer , the "expert"(who said he knew that )  refused to even look at that customer. So you see my dilemma ??? 

73 Hank K7HP 






Hank,
xDSL subcarriers are every 4.3125 kHz.  That is a common industry standard.
You will probably see carriers between 138 kHz and about 8.5 MHz, though you
could see them up to 17 MHz if the carrier is using extended subcarriers.
This range is broken up into uplinks and downlinks and are well documented
in various Internet web sources.  There is a cable/telco industry practice
to leave installed cabling in place unless there is a pressing need to
remove it.  You will need to escalate to the carrier and get them to remove
the unterminated wiring.
73,
Gordon Beattie, W2TTT
201.314.6964


-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of HankP
Sent: Wednesday, March 1, 2017 3:26 PM
To: rfi <rfi at contesting.com>
Subject: [RFI] 4khz Spectrum comb ADSL2 one last try composed as text

If this does not work I give up - I apologize for this mess  -- Hank K7HP 


I have seen nothing on this reflector about carriers  every 4 khz from
Centurylink ADSL2 systems . (or any other system)

Here is my short version of about 75 days with Clink.

A year ago Clink  finally reduced the carriers on 160 from almost S9 (-73
dBm)  out of noise to about my noise level (-100--105dBm) .Took an Engineer
from Clink in Denver turning off customers from Denver while I watched the
comb to absolutely identify the customer modem source.Then it  took over a
month for him to even find someone in Phoenix to address the issue. Clink
tech did everything under the sun except  address that customer - then two
weeks later they sent out same tech along with another tech who was a Ham
and had some idea of what a RF Carrier was. Again they addressed evertthing
from the DSLAM to my house with no effect (EVEN though they knew the
customer who had been identified by Denver) .

FInally I got them to walk the alley with me and my 160 portable DF rx. The
Ham pulled out a MFJ VHF noise receiver and we walked the alley  They
contended the problem was APS .. Nope ,its carriers guys , not noise.( I had
P3 spectrum plots showing the carriers every 4 khz - did not mean anything
to  them- and  after every change I woudl go back and run and print another
plot )   I showed them (they could listen to the speaker on my Rx.) how loud
the carriers got 100 feet or so either side of that identified customer.
The original tech left and  the Ham stayed with me . I took the ferrite
rod/jfet source follower  DFing assy I have off the R10 rx and just put the
little rubber ducky  whip on it and asked him to go probe in his access taps
and see how loud the carriers were there . He did so and admitted .Yep its
in our system.

The original tech came back and they identified numerous problems - among
which was an open pair to that customer which was forcing that modem to run
wide open (100 mw per carrier) . Interesting that the Clink Engineer told me
tey had 3 other customers within about 400 feet who either had no VDSL or
drastically reduced internet speeds. Anyhow they found a tap that had leaked
and said everything was so corroded they were reluctant to do any work there
and a crew would have to come ot and re do the whole thing . They did
replace the customer drop with a new "improved bonded and shielded  pair "
and were able to find a pair to replace the open. This got the carriers to
just at my noise level - and they said since te customer was not at home -
they would have to contact him to check it (I doubt they ever did as the
carriers never changed - and virtually every half hour their  supervisor was
calling asking why it was taking so long , this was costing Clink money- and
they could no  t afford to be worrying about this stuff !!!!! )

Well about a year passed - here come a bunch of trucks and they ran a second
cable - then about a month later  a guy comes and puts new access taps on
the new cable , and a week or so later they moved some customers to the new
taps -BUT left the old wires just hnaging - in fcat the hoiuse behind me
they just took the junction box off the wall  , threw it over the fence into
alley with wires to the old cable still in place !!!! iIts still hanging
there )  Other places they just cut off the cable and left it hanging down
in the breeze.

SOOOOO now I have carriers on 40 meters 7 to 15 dB out of my noise -100--105
dBM on 40) , on 160  5 to 7 dB out of my noise and about at noise on 80  . I
actually see two carriers on 40 about 44 hz apart probably fromtwo different
modems.

40M RX ant is M2 40M1L at 50 feet -- I can null the carriers down to noise
off end (perpendicular to phone cable)

I have talked to W0IVJ , I have talked  with Mike Gruber of ARRL and both
say they have not seen these carriers and I am the only one reporting them
!!!!!!!!! 

Curious - anyone else seeing this stuff ?? Or am i just Lucky Pierre ?

Hank K7HP

_______________________________________________
RFI mailing list
RFI at contesting.com
http://lists.contesting.com/mailman/listinfo/rfi