Here is followup & resolution regarding the RFI we tracked down about 3.5
weeks ago at the QTH of N9CJT that we suspected was DSL/VDSL as we had
identified the RFI was coming from a box and associated line on a utility
pole that were identified as Ameritech (now AT&T). Noel (N9CJT) had great
difficulty getting a response from AT&T, and finally a local ham who is a
senior regional director at AT&T wrote an internal "Presidential Letter" to
the AT&T President's Office and as a result of that internal letter Noel
received a direct call from the office of the president of AT&T on Tuesday
of this week (Oct 3rd). The response time when an internal letter like
this gets submitted is typically a response time of 24-48 hours and sure
enough the RFI was resolved yesterday (Oct 4th), and below are details for
those interested.
*Below is copied text from an e-mail from Noel (N9CJT) with names redacted
for privacy reasons.*
-------------------------------------------------------------------------------------------------------------------------------------------------
On Tuesday, October 3rd, I received a telephone call from the office of the
president of AT&T. The young lady advised me that XXXXXX (the regional
director) had been in touch and they were on it. Also on Tuesday, XXXXXX
(the regional director) received a request to forward the YouTube video
which Don WD8DSB had recorded at the beginning of September.
On Wednesday, October 4th, I received a telephone call from YYYYY, an AT&T
employee dispatched from Shelbyville, who stated that he was parked in
front of my house. He had already watched the video, and asked that I
assist not only by showing him what Don and I had found, but also by
checking again when the repairs were completed. As it turned out, he
didn't need my help -- my 10-minute drive home from work was all it took
him to find the problem. He stated that he could see immediately that the
involved pairs (2) had been damaged by lightning. He stated that the
every-4-KHz signal from 3.75 to 5.2 MHz was the normal sync-up signal that
comes every time the customer's router/modem attempts to sync up, and that
the subsequent 1.4 MHz wide hash came when that device was temporarily
successful in its efforts was also typical. He stated that there had been
an internal system trouble report on those lines, initially generated
sometime between August 11th and August 13th and persisting, and that he
was puzzled that no one had been contacted for repairs. He said it would
take perhaps 45 minutes to clear everything, so I went back to my office.
When YYYYY called again, he stated that he was ready for me to double-check
his work. I went home and found complete absence of the harmful
interference, even right at the twisted pairs on the pole. YYYYY stated
that once he had replaced the damaged pairs, the customer's router /modem
was able to sync up immediately and stay linked, and that those signals
became properly contained once balanced pairs had been restored.
--------------------------------------------------------------------------------------------------------------------------------------------------
Just FYI, and 73,
Don (wd8dsb)
On Mon, Sep 11, 2023 at 9:53 AM Jeff (W4DD) <w4dd09@gmail.com> wrote:
>
> FYI,
> Tracked a VDSL problem a year or two ago which seemed confusing at the time
> (was actually 2 DSL sources). Figured it was DSL as it had a strong
> increase in strength at 3.750MHz (this is where the DSL uplink starts).
> Ended up being a problem at two different nearby houses:
> House 1 - one of the 4 wire pairs ( 4 pairs used for increased DSL speeds)
> had a broken wire. The other wire was acting like an antenna for the DSL
> uplink.
> House 2 - DSL in the house was using split pairs, aka, one wire from one
> twisted pair and another wire from another pair.
>
> The ATT technician was excellent and found and fixed both issues. Noise
> gone after his work and both customers mentioned their Internet had not
> work
> this well in years.
>
> Jeff, W4DD
>
>
> -----Original Message-----
> From: RFI <rfi-bounces+w4dd09=gmail.com@contesting.com> On Behalf Of Don
> Kirk
> Sent: Sunday, September 10, 2023 9:04 AM
> To: RFI <rfi@contesting.com>
> Subject: [RFI] 80 meters RFI at N9CJT tracked down to an AT&T line
> (probably
> VDSL)
>
> I was asked to help locate the source of RFI at N9CJT and yesterday we
> tracked down/identified the source to be from an AT&T (formerly Ameritech)
> system and all indications are that the system is VDSL or similar.
>
> For those interested here is the link to a video that documents this case.
> https://youtu.be/3sYZTXGnLjY
>
> Once again the portable flag with DX Engineering preamp allowed us to
> quickly narrow in on the property where the RFI was originating and then we
> used a small sniffer loop to identify a specific line (cable) on the wooden
> utility pole where the RFI was emanating from, and this line turned out to
> be an AT&T line. Noel (N9CJT) will now follow-up with AT&T.
>
> Just FYI, and 73.
> Don (wd8dsb)
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
>
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