OT For John T....

John,
I know this is way off topic but how often do you get a chance to pick an experienced electrical engineers brain. And, with the HD change coming in Feb., I’m sure I’m not the only one with this problem. If this is not in your realm of expertise maybe someone else will have a solution.

All of my televisions now have a HD converter box sitting on top coupled to a tall and fairly new antenna. I get really good reception and selection, EXCEPT when a computer monitor, any kitchen appliance, shredder, or anything electric turns on, then the picture is completely knocked off until the interfering appliance stops. The picture then returns to normal. All (3) televisions react the same way

I live in a very old turn of the century farm house and still have the non-grounded, two wire circuit.

Question:
What is the best solution to my interference problem?
1. Install numerous grounding points in the system.
2. Install a television signal booster for each television.
3. Install a high joule circuit filter for each television.
4?

Dell

I assume you are using Coaxial cable from the antenna to the boxes. Twin lead will not do the trick, it is unshielded. Grounding Circuits will help in many cases, I believe a filter at each TV is the larger complex answer. Try the 40$ suppression filter power strips then progressively go more expensive until satisfied.
Tips"
Check the grounding rod on the electrical systems neutral and ground bus (these two should be bonded together) If it is a iron post, or old and corroded, purchase a new ground rod and pound it in near the Circuit/Entry box. It should be attached to the neutral with a #8 solid copper wire.
If the individual circuits to the TVs have no ground wire in them, it will probably be useless to put a filter in a circuit that has no way to "ground the spikes" replacing those may also be needed. Good luck, JimN

Jim, Thanks I will use your info.
One interesting side note, the only appliance that has no affect on the television is the vacuum cleaner. The vacuum cleaner, no matter how long it runs, does not cause interference to the televisions whatsoever. Any idea on that?

Dell, Im not up much on electronics or RFI as Jim probably, perhaps electronics gents like jdemaris and sound guy, maybe Bob or Jim can help, Im more of an old fashioned secondary AC Power Distribution kinda guy along with DC tractor electricity, but Ill toss out some thoughts.....

The more modern 3 wire household circuits can help some cuz the dedicated equipment grounding conductor would be bonded to any outer metallic cases (if any appliances have such a thing) but looks like youre stuck with the old 2 wire ungrounded.

Question:
What is the best solution to my interference problem?
1. Install numerous grounding points in the system.

I DO NOT think thats the answer or problem, you may get ground loop currents flowing which may make it worse. Besides, where you gonna bond any such "grounding points" ??? Mother earth, metallic pipes ??? Now if the TV or converter box etc has an outer metal case thay can act as a shield and even if they were tied to earth (driven rod) I guess that could help some, but a lot of electronics isnt inside any metal case nowadays

2. Install a television signal booster for each television.

I dont see that as much help either, you will just amplify the noise n static n interference, its the signal to noise ratio you gotta get down and if theres garbage in you still get garbage out. Of course if you had long runs to each TV with excess line loss that would help, but I think you have RFI about everywhere.

3. Install a high joule circuit filter for each television. If youre talking about a surge suppressor, I dont see that as the answer, thats just to bleed off any high sudden discharges to protect the equipment, not so much as a noise or static or suppression type of device, its more of a high energy spike reducer.


Things which may help, I gotta gree with Jim there. I HOPE ALLLLLLLLLLL TV CIRCUITRY IS COAXIAL CABLE because that (unlike 300 ohm flat twin lead) can redcue interference a bunch. That should be run from the antenna, to the box, to allllllll TV's.

Also as he mentioned, even thought you only have 2 wire home wiring, Id insure at the service entrance panel,,,,,,,or inside your meter base,,,,,,,or up on the weatherhead riser where power enters your house (different jurisdictions do this in diff places) the neutral is bonded to a grounding electrode conductor (like bare soft No 4 copper wire) which leads to a made grounding electrode such as a driven copper ground rod or metallic pipes etc.

Finally, the type of device you need (try Rat Shack) which may help is a noise suppressor/RFI/static/interference filter right there at the TV or box etc this is NOT THE SAME as a surge protector/supressor mind you, its for noise or static or RFI or interference etc

Another finally lol, if youre running multiple TV's and your incoming signal isnt all that stong to begin with, thats where one of those distribution amplifiers might help, it gets the antenna input n then has say 3 or 4 coax outlets
one for each TV. If that device had a noise/static/ filter and then you use coax out of it to each TV, I see that as more pretection then you currently have.

Much of this isnt all that expensive, a distribution amp and a few noise interference filters, because youre kinda stuck with that old 2 wire AC system......

John T Too Longggggggg retired EE not up much on RFI or TV stuff lol

Most vacuums are notorious for RF noise. I would call it a miracle. See if the other devices make that same static when they are plugged into the same circuit as the vacuum usually is. Jim

Yes, I have new coax antenna cable. But I just noticed that it does not have a gnd wire on it so I will add that.

I am going to install a new copper ground rod at the main box and run it to system gnd.

After that I will go with the RF Suppressor and the signa amp.

Vacuum. I wonder if the vacuum has a AC motor as apposed the the DC Rectifiers and Transformers in the PC and ampliances.

Delbert, that electrical service IS something about which I do have experience. As I posted EITHER at the Service Entrance Panel orrrrrrrrr inside the Meter Base orrrrrrrrr up at the weatherhead riser (depends on your local authority) is where the Neutral gets bonded to a Grounding Electrode such as a made one like a copper rod driven deep into the ground and/or metallic water pipes etc. Just driving a rod and running a wire to the equipment ground buss isnt what its all about, the Neutral gets mother earth grounded and inside that service entrance panel the Neutral Buss and the Equipment Ground Buss are both bonded together....

John T

John, I understood, I guess I didnt say it correctly. When I said I am going to renew the system gnd I meant AT THE SERVICE ENTRANCE MAIN FUSE BOX, not at each TV.