Digital Ballast and RF Interference

Hello, I recently posted this under the advanced section, but think it might be better posted here.


Hello,

I have a 600 watt hps with a digital greenhouse ballast. The cable company has cut off my service because they traced a cable "leak" to my house. I've had the ballast on for a couple months and haven't noticed any problems. They want to come inside and test the lines to see where the leak is before hooking my cable back up.

I made sure the ballast was in a grounded outlet. I've heard that the digital ballasts cause RF interference, but what can I do to shield this?

Thanks

I am running two of those 600w Digital Greenhouse ballasts and have had no problems whatsoever. I have Comcast cable and it's never been an issue. Let me know what you find out though as I'm curious about the outcome.

Bumping this up.

Tiredofbuyingit and I have been racking out brains on this. I'm going to try and help him out with this. I know how busy he is latley. This is what we have come up with and the suggestions we have gotten from all you great people on this board.

-the power cord or cord from ballast to light is not grounded:
how do you ground the power cord and do it saftley? Can someone provide a diagram on how to do this?

-the cord from the ballast going to the light is too long:
Someone suggested cutting it back and re-wire to light. I think we can do this. But is this the same cord that needs grounded? Someone else suggested wrapping the same cord in foil.

-Wrapping the ballast in foil.
Have no questions on this one.

Again, thank you all for your help on this one. We never saw this hurdle comeing. And I think people need to know more about this issue.

The RF comes from the lamp. There's nothing the ballast can do about it. That's the way digitals are designed to fire.....at high frequency. That's why when people take pictures of their grow with magnetic ballasts, lines show up. But with digitals, they fire faster than the camera shutter..... no lines, you dig? The only thing you can do is to insulate the grow room with a Farraday cage or something.

TheFaux said:

The RF comes from the lamp. There's nothing the ballast can do about it. That's the way digitals are designed to fire.....at high frequency. That's why when people take pictures of their grow with magnetic ballasts, lines show up. But with digitals, they fire faster than the camera shutter..... no lines, you dig? The only thing you can do is to insulate the grow room with a Farraday cage or something.

Click to expand...

Thanks for the lesson. I allways wondered what was up with the lines. Is there a way to ground it? Or are there better digital ballasts out there? Or maybe magnetic is the best way to go. Thanks again.

The Faraday cage may be easier then you think. mylar should be conductive on one side (been a long time since I checked, but it used to). If the room is wrapped in mylar, connect each panel it the next then *one* ground wire grounded. Aluminum window screening can work to. Same grounding.

Find where the RF is getting into the cable, will hold some answers.
Unplug all tvs at the wall, fire up the ballast. Probs?

Unplug all internal cables as close to the incoming to the house. Same prob?
Try a different ballast (same brand/model) Then different brand/model.

bryant228 said:

Thanks for the lesson. I allways wondered what was up with the lines. Is there a way to ground it? Or are there better digital ballasts out there? Or maybe magnetic is the best way to go. Thanks again.

Click to expand...

The interference comes from the lamp.... the BULB...... because the ballast fires the lamp (bulb) at high frequency.... that's where the energy comes out. If it's a digital ballast.... that's the way it works. There are no digital ballasts that are better than others in this regard. THAT IS THE WAY A DIGITAL BALLAST IS DESIGN TO OPERATE!

It would be easiest for you to just get a magnetic ballast.

As for the cable company.... tell them you had some wireless speakers, but got rid of them once you found out they were causing the problem. Just make sure you've taken care of the RF interference first.

TheFaux said:

The interference comes from the lamp.... the BULB...... because the ballast fires the lamp (bulb) at high frequency.... that's where the energy comes out. If it's a digital ballast.... that's the way it works. There are no digital ballasts that are better than others in this regard. THAT IS THE WAY A DIGITAL BALLAST IS DESIGN TO OPERATE!

It would be easiest for you to just get a magnetic ballast.

Click to expand...

Ok, ok, I get the point. I was just reading where Lumatek tested better then others. Althought Digital green house wasn't listed with them. Thanks for being blunt. I'm going to be purchasing a 600 watt HPS and just wanted to know for myself as well. I'm just not crazy about the magnetic ones. But might be my way to go. Thanks again Faux

Keep in mind that, as Faux states, the RF is emitted from the bulb. But thats on a correctly working system. A bad ballast can also toss out the RFI. (also a floating ground can act as an antenna.)

BigBudBalls said:

The Faraday cage may be easier then you think. mylar should be conductive on one side (been a long time since I checked, but it used to). If the room is wrapped in mylar, connect each panel it the next then *one* ground wire grounded. Aluminum window screening can work to. Same grounding.

Find where the RF is getting into the cable, will hold some answers.
Unplug all tvs at the wall, fire up the ballast. Probs?

Unplug all internal cables as close to the incoming to the house. Same prob?
Try a different ballast (same brand/model) Then different brand/model.

Click to expand...

So just "wire" the panels together? I guess it can be that simply. Then just run the wire out to a ground, like a metal pipe or a grounding rod outside? I'ts really not my call. I'm just helping Tiredofbuyingitout. He really doesn't want to buy a new ballast. But magnetic might be the way to go, or try and make a Faraday cage. Thanks for everyones help. I think we are going to try them all. Can you measure the RF with just an AM radio? Or is there an RF meter? I've read that the RF screws up the AM frequency of radios. Again, he has no issues with his cable, but his neighbors did and called the cable company.

BigBudBalls said:

Keep in mind that, as Faux states, the RF is emitted from the bulb. But thats on a correctly working system. A bad ballast can also toss out the RFI. (also a floating ground can act as an antenna.)

Click to expand...

We really, really want to test this "floating ground" theroy first. Sounds a little easier then building a Faraday cage. So, if your read my first post, what gets grounded? Just run a copper line from the end of the ground wire at the lamp connection to a metal pipe or grounding rod outside? Thanks, I hope I'm not beating this issue to death. BUt I am sooooo a novice when it comes to electrical.

If it is a bad ballast, fucking with it is going to void the warranty. He should take it back and get a magnetic ballast. They are actually more durable with a better warranty. It's going to be easier to do it like that than to try and hunt down a leak with a radio. I guarantee the equipment the cable company uses will be way more sensitive than a radio. What are you going to do when you have them come out there and find the same problem and they are going to wanna investigate? Just get a magnetic ballast and call it a day.

TheFaux said:

If it is a bad ballast, fucking with it is going to void the warranty. He should take it back and get a magnetic ballast. They are actually more durable with a better warranty. It's going to be easier to do it like that than to try and hunt down a leak with a radio. I guarantee the equipment the cable company uses will be way more sensitive than a radio. What are you going to do when you have them come out there and find the same problem and they are going to wanna investigate? Just get a magnetic ballast and call it a day.

Click to expand...

Who mentioned fucking with the ballast? A floating ground is a 'house' issue (at least as far as I talked about. I never said to open the ballast. An outlet ground with no termination in the wall isn't a ground)

Yep. cable company will use instruments in tune with their freqs and in the amplitude of 1V -P2P along with sig strength.

you could always get a little aquarium going, not with live fish, but anyone entering wouldn't need to know that, and maybe you've just taken it down to set it back up again with new fish coming, or whatever the story wants to be. if they're wondering why you have a ballast, they'll see you aquarium there with the light on, and if thats it, oh no they caught you building an aquarium. lol

but I guess that can get a little costly too. maybe you even have things in the garage/attic to help fill in meaning peices of the alibi.

BigBudBalls said:

Who mentioned fucking with the ballast? A floating ground is a 'house' issue (at least as far as I talked about. I never said to open the ballast. An outlet ground with no termination in the wall isn't a ground)

Yep. cable company will use instruments in tune with their freqs and in the amplitude of 1V -P2P along with sig strength.

Click to expand...

Thats all I really wanted to know about the grounding issue. I had a feeling you meant the outlet ground.

Just so I'm staight. What is 1V-P2P?

TheFaux said:

If it is a bad ballast, fucking with it is going to void the warranty. He should take it back and get a magnetic ballast. They are actually more durable with a better warranty. It's going to be easier to do it like that than to try and hunt down a leak with a radio. I guarantee the equipment the cable company uses will be way more sensitive than a radio. What are you going to do when you have them come out there and find the same problem and they are going to wanna investigate? Just get a magnetic ballast and call it a day.

Click to expand...

I think its safe to say I'm getting a magnetic ballast. Thanks man.

Gr8fulGreen said:

you could always get a little aquarium going, not with live fish, but anyone entering wouldn't need to know that, and maybe you've just taken it down to set it back up again with new fish coming, or whatever the story wants to be. if they're wondering why you have a ballast, they'll see you aquarium there with the light on, and if thats it, oh no they caught you building an aquarium. lol

but I guess that can get a little costly too. maybe you even have things in the garage/attic to help fill in meaning peices of the alibi.

Click to expand...

I see where you mind is going with this one. Thanks but the've allready been out once before. I don't think he has any excuses left. but to get rid of it.

bryant228 said:

Thats all I really wanted to know about the grounding issue. I had a feeling you meant the outlet ground.

Just so I'm staight. What is 1V-P2P?

Click to expand...

1V p2p is the signal on a typical cable TV line. (actually, a typical video signal) One volt peak to peak. (probably not measurable with out a *very* fast recording meter or a good O'Scope or spectrum analyzer. ) So at 1V max, doesn't take much to mess with it.

this is an old ass thread, but I had an issue today. Woke up and the cable man was poking around. I managed to kill my ballasts, then go out and talk to him. He changed a fitting and thought that was it.

Anyhow, now I know I was producing noise...How far away does the cable line need to be to not have noise introduced?