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Speak Out: DSL RFI:

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W4LGH on 2008-04-15
W8EH on 2008-04-11 said...."My problem with the phone company DSL was not radiating noise, but it was receiving my radio on 160 & 80 meters at any power. It would go 'off line' and then have to resync/reconnect to the telco every time that I transmitted.
The 'fix' was to place .01 microfarad disk capacitor right across the phone line at the jack where the modem plugged in. That cured the DSL modem from being a 'receiver'."

I am surprised that didn't KILL your DSL signal completely! DSL is an RF signal, and your DSL modem IS a receiver. You must be very close to a DSLam!!

W4LGH

W4LGH on 2008-04-15
I had DSL RFI in my shack. I found it to be the Westel DSL router. My fix, I built a screenwire cage to put the router in and grounded it to my shack ground. No more DSL RFI!

House lite dimmers...now that can send an S-Meter right on up there! I have found that the higher $$ dimmers are not as bad, but all of them seem to have their "sweet spot" that will drive you crazy! And it could be coming from your neighboors house!!

73 de W4LGH - Alan
http://www.w4lgh.com

NO9E on 2008-04-15
I could not trace any interference to ADSL/Westell modem/AT&T. I could hear very well a 13 inch TV, an old Charter DVR, and a Bluetooth-interface charger. I can also hear a single energy saving bulb.

W1RFI on 2008-04-14
Older DSL occupied spectrum to 1.1 MHz. It generally has not caused interference to Amateur Radio.

Newer DSL can extend into HF, up to as high as about 20 MHz. Developing industry standards are putting spectral masks that avoid using the ham bands, but on the band edges, this notching may not be as effective as it will be across the band. Also, notching is typically about 30 dB, so hams whose antennas are in close proximity to telephone wiring radiating DSL signals could still have interference.

One characteristic of DSL is that its use of spectrum is well defined. As one is tuning through the spectrum, the signal will dissapear rather abuptly, going from strong to very weak over a few tens of kHz.

If any hams are experiencing interference from a neighbor's DSL, please document the problem as best you can (frequency occupancy of the DSL signal, model numbers if possible) and report it to rfi@arrl.org.

ARRL is also interested in reports of interference from other equipment in neighborhing homes.

Unfortunately, the FCC has zero sympathy for interference from devices in your own QTH. Riley has offered to send out fines in those cases, but under the rules, the operator of the unlicensed device in your home would be responsible, and getting a big fine for your spouse is probably not going to go well.

Ed, W1RFI

N0AH on 2008-04-12
Yes, I concur that DSL is a problem that is underestimated and seldom gets attention- Hummm......well, I'm mad as heck and I'm not taking it anymoe!!!!!

KB9YGD on 2008-04-12
I have a verizon dsl and use a westell wirespeed modem through ethernet and it makes signals that are 40db over S9 all over 40 meters why if i were to connect the antenna to the modem i could work dx with it.They sould have made these better from this point of view.Kb9ygd

W8EH on 2008-04-11
My problem with the phone company DSL was not radiating noise, but it was receiving my radio on 160 & 80 meters at any power.

It would go 'off line' and then have to resync/reconnect to the telco every time that I transmitted.

The 'fix' was to place .01 microfarad disk capacitor right across the phone line at the jack where the modem plugged in. That cured the DSL modem from being a 'receiver'.

AG0A on 2008-04-10
Yes, I had severe RFI on 20-15 meters, haven't had 10 meters up enough to see if on that band. It caused at least S-6 noise alone and more sometimes. fixed it with some beads on the power line into the modem.

KE4ZHN on 2008-04-09
I have DSL and the only interference I get is from the DSL modem/router itself. Its very minor and of no consequence but its there. Its only noticeable on a very quiet band like 10 meters. I imagine its just the digital stuff inside radiating through its plastic case. No big deal. If I switch it off the noise goes away. I remember some of the older computers that had real crappy power supplies in them that would wipe out the entire 40 meter band! It seems like more and more RF noise in my own neighborhood is coming from peoples made in China digital junk is a bigger problem than any DSL issue. I can tune across the higher bands and hear little noises and see small carriers that this unshielded junk radiates. At first I thought it was my rigs own PLL generating birdies but I verified it with another known receiver. Plastic unshielded cases for this junk are our worst enemy. Combine this with poorly designed switching power supplies and your weak signal work is over.

K1FPV on 2008-04-09
I have had DSL for over 5 years now at 2 different locations. I've never found any interference from the DSL proper. I did trace interference to my router. Another router cured the problem along with some clamp on ferrite chokes.

I have more problems with radiation from wide screen LCD TV sets in the neighborhood along with radiation from computers and monitors.

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