DSL Causing Harmful Interference on CAP Frequencies

Started by wuzafuzz, December 20, 2016, 11:31:23 AM

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wuzafuzz

After putting up with killer noise on some CAP HF channels I finally made time to diagnose sources.  After turning off all the circuit breakers and running an HF receiver on battery power, I slowly turned everything back on while a friend (also a CAP member) monitored the radio.

We found a few noise sources. 

First was a battery charger for a portable ham radio (Tytera MD-380).  That was good for one S unit.
Second, a Motorola XPR5550 made a continuous low growl on HF.  Not worth an S unit, but annoying.
Finally, booting the DSL modem caused massive mayhem.

The modem was silent at initial power up.  So the wall wart power supply got a clean bill of health, as did the Ethernet portions of the modem/router/switch. Then all hell broke loose when the DSL negotiations started a minute or two later. My receiver went from S3 to 20 over S9!  The negotiation noises were awful and perfectly readable on my receiver and CAP Micom 2. Once the modem settled in the noise changed to constant hash, but still 20 over S9.

I can't tell whether the problem is the modem itself or DSL as a whole.  Since I can't separate the two it's hard to tell. The phone company offered to sell me a new modem to resolve the harmful interference caused by their equipment. Sorry nice call center lady, I'm not spending a bunch of cash only to discover the modem wasn't the problem.  So I'm switching to a cable provider another CAP HF guy is using without issues.  In this case the ActionTec Q1000 modem on CenturyLink DSL is the culprit.

Why post about this on CAP Talk?  I know a lot of people who try CAP HF and can't get past the noise floor caused by other electronics. Perhaps some of you will benefit from lessons learned by others.
"You can't stop the signal, Mal."

arajca

Isn't there something about consumer electronics not causing harmful interference?

NIN

Quote from: arajca on December 20, 2016, 04:16:32 PM
Isn't there something about consumer electronics not causing harmful interference?
I should know/remember this as a ham,  but my operations practice is wayy out of date.


IIRC, consumer devices are supposed to *reject* harmful interference.

Our gear isn't consumer

Sent from my SM-G920V using Tapatalk

Darin Ninness, Col, CAP
I have no responsibilities whatsoever
I like to have Difficult Adult Conversations™
The contents of this post are Copyright © 2007-2024 by NIN. All rights are reserved. Specific permission is given to quote this post here on CAP-Talk only.

SarDragon

Quote from: NIN on December 20, 2016, 05:11:27 PM
Quote from: arajca on December 20, 2016, 04:16:32 PM
Isn't there something about consumer electronics not causing harmful interference?
I should know/remember this as a ham,  but my operations practice is wayy out of date.


IIRC, consumer devices are supposed to *reject* harmful interference.

Our gear isn't consumer

Sent from my SM-G920V using Tapatalk

Nope, got it backwards. The applicable bit is Part 15, and here's what it sez (emphasis mine):

Quote from: CFR 2015 Title 47
§ 15.5 General conditions of operation.

(b) Operation of an intentional, unintentional,
or incidental radiator is subject
to the conditions that no harmful
interference is caused
and that interference
must be accepted that may be
caused by the operation
of an authorized
radio station, by another intentional
or unintentional radiator, by industrial,
scientific and medical (ISM)
equipment, or by an incidental radiator.

That's what the stickers on Part 15 gear tell us. Full text here.
Dave Bowles
Maj, CAP
AT1, USN Retired
50 Year Member
Mitchell Award (unnumbered)
C/WO, CAP, Ret

DakRadz

So Dave, for the untrained layman... I really can't quite follow that quote. I don't have the background without more information. Does that mean our devices MUST accept the interference?

Toad1168

CenturyLink is terrible.  I think smoke signals are better than their service.
Toad

NIN

Darin Ninness, Col, CAP
I have no responsibilities whatsoever
I like to have Difficult Adult Conversations™
The contents of this post are Copyright © 2007-2024 by NIN. All rights are reserved. Specific permission is given to quote this post here on CAP-Talk only.

sardak

#7
QuoteSo Dave, for the untrained layman... I really can't quite follow that quote. I don't have the background without more information. Does that mean our devices MUST accept the interference?
Yes, as long it's not harmful interference. The section has two parts:

1)Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused

2)and that interference must be accepted that may be caused by the operation.

If it can be shown that the interference is harmful, it's not acceptable. So what's harmful interference?

§ 15.3 (m) Harmful interference. Any emission, radiation or induction that endangers the functioning of a radio navigation service or of other safety services or seriously degrades, obstructs or repeatedly interrupts a radiocommunications service operating in accordance with this Chapter.

The American Radio Relay League (ARRL, the national association for ham radio) uses this example to explain the concept:
There are a lot of urban myths about Part 15 rules and devices. The first is that their signal levels are very small and it is not likely that they will cause harmful interference.
Although this is true in most cases, the radiated emissions levels in Part 15 were designed to protect one neighbor's television reception from another neighbor's video game, as an example.
The permitted radiation levels are not enough to always protect sensitive amateur reception. As one example, intentional radiators and carrier-current devices are permitted a field strength of 30 microvolts/meter at 30 meters distance from the source. On HF, this legal signal, if heard on an 80 meter half-wave dipole, would result in a received signal of S9+15 dB on most receiver S meters! This clearly would be harmful interference in the Amateur Radio Service.
[In the OP, the value was S9 +20 dB, even worse than this example.]

While this example uses the Amateur (ham) Radio Service, it is just as applicable to other designated radio services.

Here's the next kicker. If the interference is deemed to be harmful, then the user of the offending device must resolve the problem. So in the OP's case, it really is up to Eric, not the phone company, to eliminate the interference.

Here's the ARRL page on interference. http://www.arrl.org/part-15-radio-frequency-devices  and note all the specific topics in the left margin.

Mike


chief2

I have century link with the Actiontec modem that I purchased, due not have any interference with any radio equip,
that includes 6 hf and 2 vhf radios

PHall

Okay wuzafuzz, lets do some trouble shooting.
Is your phone line fed by an Aerial drop from the pole or do you have buried service?

If it's Buried, is the shield on the drop bonded and grounded at the protector?

Is the protector grounded? Per the National Electric Code, the protector shall be grounded and a buried drop shall be grounded/bonded.

Is the DSL Modem Power Supply plugged in to a Grounded Outlet?

Is the ground for your radio a "good" ground? Is the antenna ground a "good" ground too?

Eclipse


"That Others May Zoom"

wuzafuzz

Quote from: Eclipse on December 21, 2016, 01:20:33 AM
DSL?  It's 2016.
Comcast was my other choice, and they used to block VPN which I needed for work.  CenturyLink didn't block it and gave me acceptable speeds for less money.  Non-issue until I discovered the RFI.

Now that I don't need VPN like I did a few years ago, I can move around.   8)
"You can't stop the signal, Mal."

wuzafuzz

Quote from: PHall on December 21, 2016, 01:16:40 AM
Okay wuzafuzz, lets do some trouble shooting.
Is your phone line fed by an Aerial drop from the pole or do you have buried service?

If it's Buried, is the shield on the drop bonded and grounded at the protector?

Is the protector grounded? Per the National Electric Code, the protector shall be grounded and a buried drop shall be grounded/bonded.

Is the DSL Modem Power Supply plugged in to a Grounded Outlet?

Is the ground for your radio a "good" ground? Is the antenna ground a "good" ground too?

  • Buried service.
  • No idea about the shield at the protector.  It's all outside under snow.
  • Same answer re: protector.
  • Modem power supply is connected to a grounded outlet.
  • Radio electrical ground is an 8' ground rod about 10 feet from the radio.  RF ground is a 40' counterpoise wire.  Not ideal but with an HOA...  Chokes on the coax, and the ingress connectors are grounded.
"You can't stop the signal, Mal."

Eclipse

Quote from: wuzafuzz on December 21, 2016, 02:14:59 AM
Quote from: Eclipse on December 21, 2016, 01:20:33 AM
DSL?  It's 2016.
Comcast was my other choice, and they used to block VPN which I needed for work.  CenturyLink didn't block it and gave me acceptable speeds for less money.  Non-issue until I discovered the RFI.

Now that I don't need VPN like I did a few years ago, I can move around.   

Interesting, I've never known Comcast to block anything but good customer service and friendly attitudes.
They all make like Hoover, but at least when it works Comcast is the fastest on the block (unless you can get fiber, which would also solve your RFI issues).

This is your modem, right, not an AP?  Can't you just stick in a tinfoil-lined box or otherwise move it away from the radio / antenna?

"That Others May Zoom"

wuzafuzz

Quote from: sardak on December 20, 2016, 09:05:45 PM


The American Radio Relay League (ARRL, the national association for ham radio) uses this example to explain the concept:
There are a lot of urban myths about Part 15 rules and devices. The first is that their signal levels are very small and it is not likely that they will cause harmful interference.
Although this is true in most cases, the radiated emissions levels in Part 15 were designed to protect one neighbor's television reception from another neighbor's video game, as an example.
The permitted radiation levels are not enough to always protect sensitive amateur reception. As one example, intentional radiators and carrier-current devices are permitted a field strength of 30 microvolts/meter at 30 meters distance from the source. On HF, this legal signal, if heard on an 80 meter half-wave dipole, would result in a received signal of S9+15 dB on most receiver S meters! This clearly would be harmful interference in the Amateur Radio Service.
[In the OP, the value was S9 +20 dB, even worse than this example.]

While this example uses the Amateur (ham) Radio Service, it is just as applicable to other designated radio services.

Here's the next kicker. If the interference is deemed to be harmful, then the user of the offending device must resolve the problem. So in the OP's case, it really is up to Eric, not the phone company, to eliminate the interference.


Mike
Excellent research, as usual, Mike!  I'm stunned at the permissible signal levels before we approach "harmful" interference.  Pretty much everything with electricity in it is going to generate RF somewhere, but wow. 

I ran into similar problems years ago with an Ethernet switch causing mayhem on CAP VHF and a swath of amateur 2 meter frequencies.  In that instance nothing worked to resolve the problem, except replacing with a different switch.  (The offending switch was destroyed with extreme prejudice, never to radiate again.)  Similar measures may be taken in this instance.

Thanks for the scoop!
"You can't stop the signal, Mal."

wuzafuzz

Quote from: Eclipse on December 21, 2016, 02:25:28 AM
Quote from: wuzafuzz on December 21, 2016, 02:14:59 AM
Quote from: Eclipse on December 21, 2016, 01:20:33 AM
DSL?  It's 2016.
Comcast was my other choice, and they used to block VPN which I needed for work.  CenturyLink didn't block it and gave me acceptable speeds for less money.  Non-issue until I discovered the RFI.

Now that I don't need VPN like I did a few years ago, I can move around.   

Interesting, I've never known Comcast to block anything but good customer service and friendly attitudes.
They all make like Hoover, but at least when it works Comcast is the fastest on the block (unless you can get fiber, which would also solve your RFI issues).

This is your modem, right, not an AP?  Can't you just stick in a tinfoil-lined box or otherwise move it away from the radio / antenna?
I should clarify.  (Fuzzy memory after 3+ years.)  They didn't support VPN unless customers payed for business grade service.  When they started that policy my VPN on residential service suddenly got wiggy.  Interestingly enough, my co-workers in a different city didn't have the same problems with their Comcast service.  Co-workers who lived in the same town as me had the same trouble.

Yeah, this is the modem.  The embedded wireless AP is disabled since I preferred a different box and location for the AP.  Shielding the modem has no effect.  I suspect the phone line itself may be radiating.
"You can't stop the signal, Mal."

EMT-83

Quote from: wuzafuzz on December 21, 2016, 02:21:54 AM
Radio electrical ground is an 8' ground rod about 10 feet from the radio.  RF ground is a 40' counterpoise wire.  Not ideal but with an HOA...  Chokes on the coax, and the ingress connectors are grounded.

Are all of your grounds bonded to the service ground?

Spaceman3750

Quote from: wuzafuzz on December 21, 2016, 02:42:05 AM
Quote from: Eclipse on December 21, 2016, 02:25:28 AM
Quote from: wuzafuzz on December 21, 2016, 02:14:59 AM
Quote from: Eclipse on December 21, 2016, 01:20:33 AM
DSL?  It's 2016.
Comcast was my other choice, and they used to block VPN which I needed for work.  CenturyLink didn't block it and gave me acceptable speeds for less money.  Non-issue until I discovered the RFI.

Now that I don't need VPN like I did a few years ago, I can move around.   

Interesting, I've never known Comcast to block anything but good customer service and friendly attitudes.
They all make like Hoover, but at least when it works Comcast is the fastest on the block (unless you can get fiber, which would also solve your RFI issues).

This is your modem, right, not an AP?  Can't you just stick in a tinfoil-lined box or otherwise move it away from the radio / antenna?
I should clarify.  (Fuzzy memory after 3+ years.)  They didn't support VPN unless customers payed for business grade service.  When they started that policy my VPN on residential service suddenly got wiggy.  Interestingly enough, my co-workers in a different city didn't have the same problems with their Comcast service.  Co-workers who lived in the same town as me had the same trouble.

Yeah, this is the modem.  The embedded wireless AP is disabled since I preferred a different box and location for the AP.  Shielding the modem has no effect.  I suspect the phone line itself may be radiating.

They probably muck with IPSEC. I have a coworker who is currently running an IPSEC client VPN server on what I assume is Comcast consumer with no issues, and I have had a couple clients in the last 3 years who have successfully used site to site IPSEC from their Comcast home, but YMMV. This is why the cool kids are switching to SSL/TLS client VPNs.

dbaran

On the DSL interference - it is probably coming off of your phone wiring .  If you can put the DSL modem and the telco wiring further away from your radio, that will help.  When I had DSL, I had my gateway in the garage where the line came in and ran Ethernet to it.  DSL can run up to 4 MHz and the harmonics will take it  higher.  Regular phone wiring is unshielded and can act as an antenna.  The FCC rules apply to the equipment, which probably isn't radiating - but the equipment mfg can't do much about your inside wiring radiating.  If you can't move the DSL modem, you could replace the phone line with shielded cable so long as the shield is grounded (to a real ground - not to one of the phone wires).

I feel very comfortable saying that Comcast does not block VPNs.  I had Comcast until I moved and had no trouble with any sort of VPNs.  If you use the standard Comcast-supplied modem, it should work fine. 




PHall

Quote from: Eclipse on December 21, 2016, 01:20:33 AM
DSL?  It's 2016.

Some people only have access to DSL Bob. Heck I have areas here in Southern California that can't even get DSL.
It's Dial-Up or nuthin'.

Eclipse

Then those people should pack up the cows and move to where the FSM intended
for human beings to live.

I was on wireless broadband (municipal-level system similar to, but faster at the time,
then mobile cellular) until about 2 years ago, specifically so I wouldn't have to deal with
the telco or Comcast.  Sadly Sprint bought the network and shut it down, so Comcast became
the lessor of two evils.

I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.

"That Others May Zoom"

wuzafuzz

Problem resolved!  DSL service is no more.  Cable Internet is up and running with no interference to CAP HF or CAP VHF.  Although the new service costs more, I moved from roughly 40 Mbps to 100Mbps.  As a general purpose tech geek I'm not going to complain about that.

Before switching I had moved the DSL modem to a shielded box in my basement, which is where all my cable and phone connections enter the house.  Even with all other phone lines and Ethernet disconnected, the DSL service howled it's junk onto HF.  Bye bye.

It's really5 nice to finally have a collection of connectivity devices/services that don't throw RFI onto our VHF or HF channels.   :clap:
"You can't stop the signal, Mal."

THRAWN

Quote from: Eclipse on December 22, 2016, 05:08:50 AM
Then those people should pack up the cows and move to where the FSM intended
for human beings to live.

I was on wireless broadband (municipal-level system similar to, but faster at the time,
then mobile cellular) until about 2 years ago, specifically so I wouldn't have to deal with
the telco or Comcast.  Sadly Sprint bought the network and shut it down, so Comcast became
the lessor of two evils.

I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....
Strup-"Belligerent....at times...."
AFRCC SMC 10-97
NSS ISC 05-00
USAF SOS 2000
USAF ACSC 2011
US NWC 2016
USMC CSCDEP 2023

Eclipse

Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Quote from: THRAWN on December 22, 2016, 12:57:17 PM
Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....

Agreed - thankfully that is still where I live, though the US isn't even in the top 10
countries in terms of average or peak internet speeds as of 2015.

"That Others May Zoom"

THRAWN

Quote from: Eclipse on December 22, 2016, 01:08:23 PM
Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Quote from: THRAWN on December 22, 2016, 12:57:17 PM
Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....

Agreed - thankfully that is still where I live, though the US isn't even in the top 10
countries in terms of average or peak internet speeds as of 2015.


It's a sad state of affairs when the US isn't in the top 10 of everything. So continues the slide into Idiocracy...
Strup-"Belligerent....at times...."
AFRCC SMC 10-97
NSS ISC 05-00
USAF SOS 2000
USAF ACSC 2011
US NWC 2016
USMC CSCDEP 2023

wuzafuzz

Quote from: Eclipse on December 22, 2016, 01:08:23 PM
Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Definitely a pleasant surprise.  The change triggered some minor downstream projects with my home network, but that stuff is fun.   ;D
"You can't stop the signal, Mal."

Briank

Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.

Fortunately in my area, DSL is cheaper than dial-up now.  :-)  $23/mo DSL + $5/mo UNE charge vs. $20/mo line charge + $10/mo dialtone charge + $10/mo dialup service.  :-)

The high speeds don't gain as much as you'd think, so perhaps dialup still is viable for basic surfing/e-mail?  My DSL is only 1.0 Mbps, but I have no trouble streaming video.  Not in HD of course, but I don't have HD screens either.

Back on topic, it's really surprising to hear about DSL causing RFI issues.  I can't recall ever hearing that before.  I always hear about cable causing the RFI problems.

PHall

Quote from: THRAWN on December 22, 2016, 01:11:32 PM
Quote from: Eclipse on December 22, 2016, 01:08:23 PM
Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Quote from: THRAWN on December 22, 2016, 12:57:17 PM
Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....

Agreed - thankfully that is still where I live, though the US isn't even in the top 10
countries in terms of average or peak internet speeds as of 2015.


It's a sad state of affairs when the US isn't in the top 10 of everything. So continues the slide into Idiocracy...

Yeah, take a look at the size of the countries that have better internet speeds. They're all a lot smaller then us.
Our problem is that we're so big. And as long as we're using land based methods (copper cable and fiber optic cable) it's going to be a problem.

Holding Pattern

Quote from: PHall on December 25, 2016, 04:16:47 PM
Quote from: THRAWN on December 22, 2016, 01:11:32 PM
Quote from: Eclipse on December 22, 2016, 01:08:23 PM
Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Quote from: THRAWN on December 22, 2016, 12:57:17 PM
Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....

Agreed - thankfully that is still where I live, though the US isn't even in the top 10
countries in terms of average or peak internet speeds as of 2015.


It's a sad state of affairs when the US isn't in the top 10 of everything. So continues the slide into Idiocracy...

Yeah, take a look at the size of the countries that have better internet speeds. They're all a lot smaller then us.
Our problem is that we're so big. And as long as we're using land based methods (copper cable and fiber optic cable) it's going to be a problem.

Yup, between population size and population density, we have a series of obstacles that pretty much mean that with the exception of Russia, China, and India, everyone will have an easier time getting broadband to all than we will.

With that being said, wireless broadband is making serious headway in rural zones.

PHall

Quote from: Mordecai on December 27, 2016, 10:41:46 PM
Quote from: PHall on December 25, 2016, 04:16:47 PM
Quote from: THRAWN on December 22, 2016, 01:11:32 PM
Quote from: Eclipse on December 22, 2016, 01:08:23 PM
Quote from: wuzafuzz on December 22, 2016, 11:02:01 AM...Cable Internet is up and running...

Not to be missed here - new cable service installed and working in what, three days?  A Festive Miracle!

Quote from: THRAWN on December 22, 2016, 12:57:17 PM
Quote from: Eclipse on December 22, 2016, 05:08:50 AM
I have no idea how anyone with even normal internet needs, let alone work needs,
could use dial-up these days.


First world problems....

Agreed - thankfully that is still where I live, though the US isn't even in the top 10
countries in terms of average or peak internet speeds as of 2015.


It's a sad state of affairs when the US isn't in the top 10 of everything. So continues the slide into Idiocracy...

Yeah, take a look at the size of the countries that have better internet speeds. They're all a lot smaller then us.
Our problem is that we're so big. And as long as we're using land based methods (copper cable and fiber optic cable) it's going to be a problem.

Yup, between population size and population density, we have a series of obstacles that pretty much mean that with the exception of Russia, China, and India, everyone will have an easier time getting broadband to all than we will.

With that being said, wireless broadband is making serious headway in rural zones.

Just one of the reasons AT&T brought Direct TV. But the speeds offered on Wireless is still much slower then wireline broadband.
But, the technology is changing at a fairly rapid rate. So who knows what will be offered in a year or even 6 months.

Luis R. Ramos

QuoteBy PH:

Just one of the reasons AT&T brought bought (FTFY) Direct TV. But the speeds offered on Wireless is still much slower then wireline broadband.
But, the technology is changing at a fairly rapid rate. So who knows what will be offered in a year or even 6 months.

Squadron Safety Officer
Squadron Communication Officer
Squadron Emergency Services Officer