[RFI] 80 meters RFI at N9CJT tracked down to an AT&T line (probably VDSL)

Thu Oct 5 10:13:09 EDT 2023

Sounds like AT&T knows it has a problem with responsiveness, to have set 
up such an intervention mechanism.  Good to see.

73, Pete N4ZR

On 10/5/2023 9:32 AM, Michael Carter wrote:
> Thanks for the detailed update, Don.
>
> It is a bit intimidating to think that
> resolution of similar RFI issues might
> require high-level intervention at
> the level of a major corporation's
> president's office!
>
> 73,
> Mike, K8CN
> ________________________________
> From: RFI<rfi-bounces+mike.carter=unh.edu at contesting.com>  on behalf of Don Kirk<wd8dsb at gmail.com>
> Sent: Thursday, October 5, 2023 9:26 AM
> To: Jeff (W4DD)<w4dd09 at gmail.com>
> Cc: RFI<rfi at contesting.com>
> Subject: Re: [RFI] 80 meters RFI at N9CJT tracked down to an AT&T line (probably VDSL)
>
> CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
> 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 at 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 at contesting.com>  On Behalf Of Don
>> Kirk
>> Sent: Sunday, September 10, 2023 9:04 AM
>> To: RFI<rfi at 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://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2F3sYZTXGnLjY&data=05%7C01%7Cmike.carter%40unh.edu%7C18539993b573491d02b508dbc5a6cf63%7Cd6241893512d46dc8d2bbe47e25f5666%7C0%7C0%7C638321092464297354%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=JDaQF2F3flvdCcBJQCJ7RaXJ8oUYFv5w2FigWXAP30Y%3D&reserved=0<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)
>> _______________________________________________
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>>
>>
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