Hank, K7HP,
The carriers are likely 4.3125 kHz center to center.
Unless you can identify the three specific modems through their induvidual
signatures, you may find that there are three leaky spots in the twisted pair
cable.
I work for another carrier that operates a similar system but with somewhat
different parameters and have lots of experience with our system and because of
this list other systems, including CenturyLink.
Just curious, does the downlink signal drop off around or below 8.5 MHz? Also
is there an uplink signal from roughly 3.7 to 4.5 MHz? Does CenturyLink offer
Video as well as Data over VDSL2 in your area and is it coupled with POTS or
VOIP telephone? Signatures can be derived pretty quickly if you know these
characteristics of their service.
If you need a hand, call me or contact the ARRL Lab guys and send them a
Broadband Interference Report form ask them to forward it to me for analysis.
73,
Gordon Beattie, W2TTT
ARRL EMC Committee Member
NNJ Section Technical Advisor
Bergen County DEC
201.314.6964
W2TTT@ATT.NET
Get Outlook for Android
On Thu, Feb 20, 2020 at 9:47 PM -0500, "HP" <pfizenmayer@q.com> wrote:
Resend -never saw it appear
----- On Feb 7, 2020, at 2:57 PM, pfizenmayer wrote:
| Are there any ADSL2 gurus on this reflector -- I have carriers every 4 khz
| 160/80/40
| and obviously three modems causing it as I can null any one of them at a time
| (they are a few cycles apart and can see them separately with P3 scan at 2
khz.)
| Worst case after I have transmitted so the system brings all modems up to max
| the levels on 160 are -80 -90 dBm and sometimes as much as -70 dBm. on 160.
| BUT several evenings about 10 PM local I have seen another set of carriers
again
| spaced 4 khz but between the original set -noise level will also rise about 5
dB
| before
| a beep and the carriers appear then only on for a few seconds and all goes
away
| and that
| may repeat three or four times in an hour or so. I have audio recordings but
| hard to catch
| a P3 screen grab.
| So anybody know are the ADSL/VDSL systems looking at doubling the number of
| carriers ???
| This is a Centurylink system in Phoenix , Az.
| I wish when ARRL proclaimed that ADSL/VDSL was not going to be a problem in
| Phoenix
| that they had checked where there were overhead lines not just buried.
| Hank K7HP
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|