RF in the shack!

[KA9MOT]

I posted this over on the Zed so I thought I'd copy and paste it here too.

I have a homebrew OCF dipole at 40 feet and a Butternut HF-9V vertical out in the yard. When I key my rig at any power (5W to 100W) it knocks out my internet (DSL with WiFi), but bothers nothing else. I've installed 10 Ferrite beads as well as Ugly Chokes at the antenna end (Both antennas) and at the switch in my shack (both antennas and both radios). That is a total of 60 Ferrite beads (I purchased a bag at a hamfest 1 time and this is the first time I've needed them. They are supposed to be Type 31 material but are not marked). Still, it kills the internet.

I'm thinking my problem might not be with my station and I am out of Ferrite beads, so I ran about 10 turns of the phone line feeding the DSL Modem through a T130-2 Torroid on both ends. My problem still persists.

I'm using RG-213 from the antenna switch to antennas (Both of them) and RG-8X from rigs to switch. Both switches are connected together with one of those double pl-259 adapter thingies (Sorry to get so technical).

Also, this happens when transmitting into antennas or dummy load. No beads on Dummy load. I relocated my DSL Modem to the opposite end of the house away from shack and antennas.

Does anybody have any other ideas? I'm about to pull my hair out.

[NA4BH]

Try it without all the connections between rig and antennas. Hook up antennas direct.

[KA9MOT]

I forgot to mention that I did exactly that. Even just rig to dummy load with a 3 foot jumper. And it still knocked the internet out.

[NA4BH]

Did it start all of a sudden (have you been using it without any problems prior)?

[NQ6U]

Of course you have RF in the shack—it's full of transmitters. Just get rid of them and your problems will be solved.

Seriously, I'm guessing it's a bad engineering job on the DSL modem. Poor RF shielding is the usual suspect when it comes to RFI with consumer electronic equipment.

[KA9MOT]

Did it start all of a sudden (have you been using it without any problems prior)?

Only with this modem and the Heathkit. Previously I had cable. Same antennas. No problem with cable.

[NA4BH]

What modem are you using? Westell by chance?

[KA9MOT]

Seriously, I'm guessing it's a bad engineering job on the DSL modem. Poor RF shielding is the usual suspect when it comes to RFI with consumer electronic equipment.

I think you are correct. I just can't get my head around how RF is getting to it. That dummy load might be radiating a little, but not much.

[KA9MOT]

What modem are you using? Westell by chance?


Yes, Westell! Should I hook my WiFi router up to it and then wrap it in Tin Foil?

[KA9MOT]

Dad gum! Pushed the wrong button!

[NA4BH]

Does it look like this?

http://farm3.staticflickr.com/2052/2237262925_ac5e158e98.jpg

[KA9MOT]

Westell 7500

5539

[NA4BH]

Well, CRAP. I have two of the previous mentioned DSL modems that are collecting dust. One used, one new.

Do you have the filters(DSL) hooked up to each phone? Does it do it on all bands? 10 meters eats up TV here.

Should anybody need the DSL modem that I showed in the picture, let me know. Mi modem(s) es su modems.

[KA9MOT]

I think 2 or 3 more days of people yelling at me for killing the internet and I'm going to swallow my pride and call the cable company. I wonder if I can buy a better DSL Modem and use it on Frontier's system and find one that is immune to RF.

Yes, I have the filters on each phone and they are both in other rooms, at the far end of the house (about 40 feet away). And yes on all bands, but nothing else seems to be effected.

[KA9MOT]

DANG IT! I did it again!

[KA9MOT]

Well, CRAP. I have two of the previous mentioned DSL modems that are collecting dust. One used, one new.

Do you have the filters(DSL) hooked up to each phone? Does it do it on all bands? 10 meters eats up TV here.

Should anybody need the DSL modem that I showed in the picture, let me know. Mi modem(s) es su modems.

Did you have problems with your modems and RF?

[NA4BH]

NO.

[KA9MOT]

I'm looking at their site as well as a Westell Forum and I don't see anything that will help.

[KA9MOT]

I just had a look at some reviews for this modem. It turns out it is a pile of junk. Very poor reviews......

[PA5COR]

Phone your company that provided the modem, explain your problem and ask/demand a modem that complies with the code, that is how it works here, on my side of the pond all equipment must comply with the minimum CE code, and withstand 20 volt per meter H.F.
Some modems here from cable or ADSL can give problems, but cable and ADSL providers will swap them for better ones if costumers complain.
I caan make 1000 watts in any antenna, with the modem and router 2 feet away from my gear, it's behind the cabinet my hamgear and amplifier is situated in.

No problems too with neighbous running that power too.
If you used an dummy load your modem is your problem, so contact the firm that provided it.

[N8YX]

Have you confirmed that this problem does not happen with any other radio? If I'm reading your commentary correctly, two​ variables have been introduced into the equation.

[KA9MOT]

All 3 radios that have been run in this shack since I switched to DSL have caused this.

They are: Heathkit HW-101, Kenwood TS-570S and Ten Tec Scout. All three with feedline connected directly to the rig, or through switches. The Heathkit had some issues, so I blew it off as something we all could live with.

[KC2UGV]

Does it in fact knock out your wifi and DSL? Or, just the DSL, or just the Wifi?

I'm betting, that the wall wart for one of those two devices is crap. Ferrites on the power lead for whichever one (Or both) will solve it. What model is your wifi router?

[K7SGJ]

Steve, you you have anything else on the phone line like a security system, remote ringer, or something?

Also you might try just taking everything of the phone line except the router temporarily.

[KA9MOT]

It is a WiFi DSL router. All in one unit. The "Internet" light turns off but the unit does not reboot. After a minute or so, the "Internet" light comes back on and we are good to go until I key the rig. It is a Westell 7500

[KA9MOT]

Steve, you you have anything else on the phone line like a security system, remote ringer, or something?

Also you might try just taking everything of the phone line except the router temporarily.

Nothing. 2 phones and that is all. Phone calls are not disrupted. I'm not sure if that means anything at all. I will try removing the phones and see what happens.

[K7SGJ]

Corey has a point about the wall warts. Some, the type w/o the switching supply, just have a xfmr and a couple of diodes in them and do the filtering and regulation in the box. It's worth looking at.

[KC2UGV]

It is a WiFi DSL router. All in one unit. The "Internet" light turns off but the unit does not reboot. After a minute or so, the "Internet" light comes back on and we are good to go until I key the rig. It is a Westell 7500

Yeah. Put a bead on the wall wart power cable, near the router. I bet it solves the problem.

[W3WN]

I think you are correct. I just can't get my head around how RF is getting to it. That dummy load might be radiating a little, but not much.You'd be surprised at how well a dummy load can radiate. I can still remember the night when N3WS checked into the WPA traffic net with an extremely weak signal, which had those of us in the K3CR shack scratching our heads (Walt lived a couple of miles from campus, so he should have been booming in). Turned out he was still on the Cantenna.

If the internet modem/device has a plastic case, and most of them do, there's very little to keep the RF out.

And try a ferrite bead or filter on the AC power cord. You'd be surprised at how well those can be as antennas sometimes.

[W3WN]

All 3 radios that have been run in this shack since I switched to DSL have caused this.

They are: Heathkit HW-101, Kenwood TS-570S and Ten Tec Scout. All three with feedline connected directly to the rig, or through switches. The Heathkit had some issues, so I blew it off as something we all could live with.
DSL? Hmmm.

The fact that it's happening with three different HF rigs from three different manufacturers & three different eras of construction leads me to rule out the transcievers themselves as the cause. They're the trigger (or your transmitting is) but not the cause. Also, the fact that this didn't happen before you switched to DSL also leads me to believe it's not the antenna or the cable. So we've narrowed it down to the DSL box.

Keep in mind that the DSL signal is coming in on unshielded twisted pairs. Something in the system is acting like enough of an antenna to funnel in enough RF to knock the DSL modem out. A ferrite choke on the incoming phone line would definitely help.

[WØTKX]

Wall wart ferrite beads, maybe, but I'd try one of these...

DSL Phone line filter, from Home Depot

(http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=202698785&storeId=10051&langId=-1&catalogId=10053&cm_sp=BazVoice-_-RLP-_-202698785-_-x)
Or, this one, because I like the name. :hyper:

http://www.ky-filters.com/ (http://www.ky-filters.com/)

[NQ6U]

Those Home Despot things are for filtering out the DSL frequencies from the voice frequencies so you don't hear a buzz when you're using your telephone. They won't help with RFI issues at all.

[WØTKX]

Umm, yea, my bad. Not (and never have been) a DSL user.

The correct one would be a telephone RFI filter, like the "KY".

http://www.tomthompson.com/radio/Telephone%20Filter/telephone.html

[KA9MOT]

OK, I made some progress. I used a T130-2 torroid on the wall wart power cord. About 10 turns. 40M and down I still have problems with 5W. 20M and up it works FB at 100W. I no longer have problems on the dummy load on any band using 100W. I did not test on 160M or 30M.

[W2NAP]

id find a better built wallwort.

[KA9MOT]

id find a better built wallwort.

I already tried that. I used the wall wart that came with my D-Link WiFi Router which previously had no problem and it didn't help.

[KA9MOT]

K1DNR posted these two sites over on the zed:

http://vk1od.net/measurement/icm/index.htm

http://www.ifwtech.co.uk/g3sek/clamp-on/clamp-on.htm

I think a project is in my future! I have everything I need except the meter.

[K7SGJ]

K1DNR posted these two sites over on the zed:

http://vk1od.net/measurement/icm/index.htm

http://www.ifwtech.co.uk/g3sek/clamp-on/clamp-on.htm

I think a project is in my future! I have everything I need except the meter.


I'll look around. I may have one out of an old high voltage probe. I just can't recall if it's 100ua.

[KA9MOT]

That would be very cool. I was going to run down to the radio shack tomorrow but I doubt they have anything.

[K7SGJ]

Well, you could always tear one out of their analog meters. Take the case and mb back and tell them it doesn't work. Probably be a week before they realize the movement is missing. They are 100ua FS as I recall.

[KA9MOT]

Hmmmm........

[KJ3N]

I'm still scratching my head trying to figure out how the fuck you get RF into a DSL modem when on a dummy load. Is the modem sitting on top of the dummy load?

What kind of dummy load is this?

[KA9MOT]

No, the modem is at the end of the house (about 40 feet away) and not near the antennas or feedlines. The phone lines might cross the feedlines in the basement. I am sure they do.

BTW, since putting the T130-2 on the power line to the modem the Dummy load does not cause problems.

EDIT: The Dummy Load is an old Drake DL-300....300W if I remember correctly.

[KJ3N]

BTW, since putting the t130-2 on the power line to the modem the Dummy load does not cause problems.

That would indicate to me that the phone line, the AC line, and the feedlines are all running next to each other. Like right on top of each other.

[KA9MOT]

I don't walk well and can usually get down the basement stairs but then have to crawl up them. Some days I do better, so the nest time I'm feeling spry, I'll go down there and have a look.

My wife is afraid I'll fall down the stairs and I have but I've always been at the bottom when I did. 1 or 2 stairs is only a bump.

[KC2UGV]

I'm still scratching my head trying to figure out how the fuck you get RF into a DSL modem when on a dummy load. Is the modem sitting on top of the dummy load?

What kind of dummy load is this?

Through the AC lines. I'm suspecting a less-than-perfect electrical safety ground system.

[KA9MOT]

Through the AC lines. I'm suspecting a less-than-perfect electrical safety ground system.

I don't know. Nothing else in this house is affected by this. No cheap computer speakers or anything. My neighbors say they are having no trouble. My old cable modem lived right here in the shack and was unaffected by my radios.

I think it is a crappy cheap modem.

[KC2UGV]

I don't know. Nothing else in this house is affected by this. No cheap computer speakers or anything. My neighbors say they are having no trouble. My old cable modem lived right here in the shack and was unaffected by my radios.

I think it is a crappy cheap modem.

Well, it's a combination.

Many things are somewhat resistant to this sort of thing, either through purposeful design, or by accidental design. I think it's a crappy design for the Westell modem, coupled with a less-than-perfect (Not saying defective, just not-perfect) electrical grounding system.

My DSL modem kicked over every time I keyed up on 30M, until I added toroids to the power lead. Yes, I have a less-than-perfect electrical ground, and less-than-perfect station setup.

As for the crap design, there's a reason they can give away those modems. A DSL interface for a piece of Cisco gear runs about $400 bucks. And, it's just a small card like this:
http://www.cisco.com/en/US/prod/collateral/routers/ps221/images/0900aecd803638d7_null_null_null_04_26_05-1.jpg

But it will NEVER have an RFI issue, no matter how crappy the station is setup. Given the fact that DSL uses HF frequencies, it's not all that surprising a cheaply designed interface will have issues. Cable uses UHF, if I recall correctly.

[WØTKX]

If you have an old AM portable, yank out the ferrite bar antenna, remove the coil, and wrap the telco wire around it.

For a "cheap" potential fix. A friend who got horrible RF into his computer speakers used 'em, and this fixed it.

[KA9MOT]

Well, I got to thinking about it and realized the Phone Companies Drop from the pole was about 20 feet away from the OCFD running parallel with it, and only 2 or 3 feet away from my Butternut. I placed 5 of the snap on ferrites on the phone line where it enters the house and my problem appears to be resolved.

Thanks for all of your help!

[KJ3N]

Well, I got to thinking about it and realized the Phone Companies Drop from the pole was about 20 feet away from the OCFD running parallel with it, and only 2 or 3 feet away from my Butternut.

That would do it. :doh:


I placed 5 of the snap on ferrites on the phone line where it enters the house and my problem appears to be resolved.

:clap:

[KA9MOT]

That would do it. :doh:



:clap:

Yes! :clap: :clap: :clap:!

[WØTKX]

Stupid ferrite tricks work, eh?

Frozen legumes...

[KG4CGC]

Allswell that endswell!

[KA9MOT]

You know, I still had an occasional problem with that DSL modem on 75M...... So I dumped it and switched back to cable...... DOuble benifits....the DSL was 2MB sec on it's best day and cable is 24MBs on it worst day, and no more RFI..... It's a good day in the shack.