RFI cable internet

[Detroit47]

      Hi guys I need help. My wife and kids play online games, and I kick them off line when I key up on 75 meter’s. Let me go into detail we have an Xbox 360 that is online hooked up to Comcast cable through a hardwire router no problem I don’t bother it. But when they are playing World of Warcraft on a Pc they say I cause them to lag or get disconnected. I have three pc's and the Xbox all hooked up to a central router. The router is a hardwire type using cat6 cables. I have tried clamp on ferrite beads on the cat6 cables going from the router to the Pc's. This seems to help some, but is not a cure. The ground rod for the cable system is only three feet long and close to my station ground. Is this a problem? I'm not sure where the RF is getting into the system at. I wonder if I was to sink an 8 foot ground rod for the cable further from the station ground if this would help. I am open to any suggestions I'm not sure how I can isolate where the Rf is getting into the system at. I suspect the cat6 cables because they are unshielded.   
       When I key up on ten meters this isn't a problem. Only on 75, and the ground rod for the ten meter station isn't near the cable system ground rod.

Help 73 N8QPC

[ke7trp]

Try a Counterpoise on the transmitter.  Information is in the johnson manual

C

[flintstone mop]

Clark might have the solution.
It does seem like RFI inside the house. Usually the cable system is fairly well shielded.
Cable TV in the air or underground?
In the air might need a common mode filter to get RF off the shield.

Fred

[k4kyv]

I have just the opposite problem.  The transmitter doesn't bother the internet cable service (other than my audio getting into the computer sound card).  But the cable modem spreads hash all across HF, even though the shack is a separate building over 50 ft from the house.

Recently replaced the cable modem.  The old one had a heavy duty cast metal case.  The new one has a cheap plastic case, but spews out less garbage than the old one.

[W1RKW]

Ground rods I would think should all be bonded to the service entrance ground.

Make sure your cable TV cables are crimped properly and are secured tightly to the equipment, not hand tight.  You want to eliminate any leakage in and out of the cable TV cable.

[ke7trp]

I have a Friend that has this same problem. He put Counterpoise wires out along the base board.  Solved.  Later he got an MJF artificial Ground.  He said you could really see the current change when tuning the box. 

Take a simple volt meter,  Hold the neg in your hand.  Place the positive on the Transmitter Case when its keyed.  If you see volts there.  Its hot with RF.  Placing a counterpoise wire on the transmitter will solve this and remove the RF. 

What you are going to need to do to find this is a signal strength meter or a small handheld Short wave radio. Key up and walk around and start testing the signal. 

A friend found that at his house, The Cable TV line ran under the Eve of the Roof and then into the house. This was HOT with RF. After making a Choke and placing it on that cable, The issue was solved.  His signal strength meter would peg when he got to that Cable TV line... It was easy to locate

Sometimes, Its just not feasable to run Ground rods in.  Renting, Second floor install, basement install ect..  I have done alot of work around here in this respect. Even with Open wire line right in the room, There is little RF in here.

Good luck

Clark

[k4kyv]

I tacked counterpoise wires under the floor joists of my shack, cut for 40m.  They drastically reduced the rf I was getting into my speech equipment on that band.  I can  load up the transmitter, and go under the shack and light up a neon lamp by holding it close to the ends of the counterpoise wires...

...And that is with a good solid ground on everything and the antenna 140 ft. away.  One problem is that the higher you go in frequency, the harder it is to find genuine zero rf ground potential.  Even just a few feet of wire lead can render the earth ground completely ineffective.

[Detroit47]

Well it looks like I'm just plain screwed. Being that I am on such a small lot I have to pass one leg of the dipole over the house. The RF is just plain radiating into the house. I walked around with 2 different field strength meters and they don't move, until I touch something metallic. If I touch a piece of furnace duct with the antenna it pegs it out. The same with the TV/internet coax it is even on the ground of the house wiring. I don't think there is much hope. I think that these things are acting as an antenna. I am clueless on how to set up a counterpoise. I don't bother the TV or the internet just their World of Warcraft game. I put a new ground on the cable system with flat copper strap but no help. I even disconnected the cable from the outside line to see if there was still RF on the line. There still was as far as I can see. The antenna is just too close to the house to get away from the RF. I guess I can only talk when they aren't on their game.

73 John N8QPC

[ke7trp]

Read the EF johnson transmitter manual.  You can cut a counterpoise and lay it on the floor along the shack.

C

[Detroit47]

Well I seem to have a little hope of getting out of my computers. After researching the idea of a counterpoise it didn't seem feasible for my application. I spoke with an engineer at the Phone Company whose specialty is grounding and RF shielding.He is a ham also and has consented to help me straighten out the problem. The first thing I need to do is buy about 10 pounds of ferrite cores. I also need to put in a ground stake at the service entrance to my house. My house was built in 1954 and at that time they only ran a 3 wire system in the house. And the neutral is bonded to a cold water pipe no earth ground. Of course my meter is over my patio so I have to drill a hole in the concrete for a ground stake. I am going to put the ground stake in the basement since I have to drill through concrete I might as well do it where it will be easy to wire. I am also going to ground the ductwork on the furnace. I don't have anything to lose with the exception of my sanity.

73 John N8QPC

[KD6VXI]

Of course my meter is over my patio so I have to drill a hole in the concrete for a ground stake. I am going to put the ground stake in the basement since I have to drill through concrete I might as well do it where it will be easy to wire. I am also going to ground the ductwork on the furnace. I don't have anything to lose with the exception of my sanity.

73 John N8QPC

Be CAREFUL with the hole in the basement.

If you do it, do it when it's DRY out (like, this summer, MIDDLE of summer), and then get a good 2 part epoxy you can inject into the hole.

Otherwise, get a DAMN good sump pump, JUST IN CASE.  A couple good drenchings and your 'ground rod' entrance can become leaks galore.

As to grounding the ductwork, I can apply this (which vaguely can approximate the same thing).  In my CB days, I found that my 77GMC AND my 84 Suburban had tailpipes that where a quarter wavelength long.

Grounding them at 3 points (each end and in the middle) made a HUGE difference in both RX and TX signal strength!   I also lost a LOT of motor noise, once that quarter wave was 'disected'.

I'd bet your furnace ducting could be something near the same....

--Shane

[flintstone mop]

Hey Yo John!!
Several posts here have mentioned that grounding and ground rods are not your solution.
Someone here who is quick with numbers what does John need in length for the "counterpoise".
 
What all this magical talk is, John is you are going to connect whatever length of hookup wire to the case of your transmitter. There's got to be a screw you can loosen to connect just one wire a certain length. Just run the wire around your shack along the wall, anywhere. If you have funds for an artificial ground made by MFJ then you follow their instructions.
Cawman guys............1/4 wave for 38??? His problem is when using 75/80M.
Sometimes Google is my friend. I cannot find a common mode filter for CATV. Your problem is RF comming in on the GROUND or SHIELD of the cable and messing up the Xbox. That's why grounding will not cure your problem.
Fred

[KD6VXI]

John,

This is a longshot, but it fixed my problems with my home theater PC.

Try a wireless keyboard / mouse / trackball / whatever_pointing_device_floats_your_boat.  I had one on 27 mhz, didn't work worth a darn.  Every time my kids would play with their RC cars, I'd get jibberish on the screen.

I went to a bluetooth keyboard / trackball, NO more problems.

Friend in So Cal had the same problem, no matter WHAT band He'd use.  EVERY time he'd key up, any mode, it would hang the PC.  RF was getting in through the PS/2 lines on the keyboard.  Ferrite snap-ons took care of that.

RF is getting in, but it's NOT always via the cable modem...  Since it's ONLY on the PC that you are having problems with, I doubt it's COMING in via the cable line.  The cable line may be RERADIATING it, but it's secondary to the interference..  It's also not coming in via the network, although it COULD be causing havoc on the Cat (X) leads going in and out of the network card on the PC...  (unless you're using wifi).  I'd shield the Cat5 or Cat 6 or whatever leads your using both on the router / hub side and the desktop side.  Maybe an EXTRA on the desktop side.  And also ferrite the heck out of ANY leads coming in and out.  Speakers on the PC are EXCELLENT antennas for interference. 

Or, go ask one-o-dem boys runnin pairs of 20s how they can keep on paltalk AND key 80 grand.

--Shane

[flintstone mop]

BlueTooth is neat stuff but can mess up your cordless phone and or wireless network. You will have to be aware of the freqs used by any cordless phone you have at home and if you are using a wireless internet.
The newer faster wireless rooters and the 5.7ghz cordless phones won't be bothered by Blue Tooth (2.4GHZ)

Fred