Questions: RFI Problems & Outdoor Ground / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Questions: RFI Problems & Outdoor Ground

previous 1 2

Move Thread

LAN_403

quicksilver

Sun Mar 28 2010, 08:43PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

Well I have heard opposing answers here with logic to both. Remember I live out in a very clear desert (minimal competing signal strength) and am using the classic Earth-Ground. but yet in other posts I have read knowledgeable folks speak of using third wire grounding in a little apartment IF the coil is low powered (300w or less).

Is it POSSIBLE that my little SGTC with that big old "rod in the earth" ground IS getting out? I am going to try one more test tonight.

I am pretty cautious about running into the house ground as I don't want to fry some pretty fun electronics. There is no shakiness to the topload, a needle provides a breakout. I also think that I get better performance with the outdoor-type of classic ground. This is really a small coil but I got lucky as everything seems just right for efficiency.

I really don't want to piss-off the neighbor; so just one more try. And note: the weather we get in AZ is somewhat unique. We get some of the clearest sky's you'll ever see and a period of Monsoon like S Asia. I know there are some guys on the Board who live in AZ & they run some SERIOUSLY BIG coils (I've seen them).
I would bet that they could shout down the neighborhood with their RFI.....(no?)

P.S.

From a meteorological standpoint, the conditions are variable to the extreme; anyone who has been here will say that. The Gov't had to collaborate with the University to work on the issue of Mexico / USA signal mixing crossing. And that has really never been completely solved: it's said - due to atmospheric (or Intelligence) conditions.

radiotech

Sun Mar 28 2010, 11:09PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

As far as TVI is concerned, if the coil is powered from house wiring, the house wiring is part of the problem, as is the length of wire to the earth rod.

wylie

Mon Mar 29 2010, 03:01AM

Registered Member #882 Joined: Sat Jul 07 2007, 04:32AM
Location:
Posts: 103

That sounds like me except that the pesky neighbour and the Ham are both me.

His post made me think about a Hams vs. Coilers Armageddon...till i realized there's a lot of crossover. The coilers would still win IMO.

Also, want to 2nd what EVR said about RF power. There's definitely a difference between noise and "power". You're neighbor could definitely be getting interference even though he can't light a fluorescent in hand at the same time. The weak-signal conditions make it seem even likelier.

Your neighbor sounds pretty cool, why not arrange a test. Power up the coil while he tries different channels. See if y'all can't work out a schedule. Get him to come watch lol, then his TV reception won't matter while the coil is on

radiotech

Mon Mar 29 2010, 05:44AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

Hams, through the legal arm of the ARRL, have been lobbying against engineering errors made in the certification arguments for BPL. Hams are adept at finding sources of RFI.

quicksilver

Tue Mar 30 2010, 06:54PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

QUOTE:
"As far as TVI is concerned, if the coil is powered from house wiring, the house wiring is part of the problem, as is the length of wire to the earth rod."

Could briefly expound on that? Is this a question of "hit or miss" in terms of the length of lead-out to the rod or is it something that could be filtered out? My only other course aside from not using that earth rod is to use a ground within the home.

Because, I really don't know what to say other than I am not going to light that thing up outside in the manner I had been anymore. I didn't want the neighbor to get ruffled but I asked him (after I had done one more little session) and it IS the coil. I can't see it being anything else. He DID get some noise (don't know exactly what he got as I just want to quietly not do that again....) ;-0

His words: "Yea it happened again on Sunday...."
Me: "You got interference?"
Neighbor: "Yea at X(time period) I got all the 'crazy crap'"
Me: "did it go away? What sort of stuff did you get?""
him: "Yea, after a bit: couldn't get anything on the TV. I can't explain it; do you get all that garbage too?"

I really like the guy or else this could have been the setting for a pretty stupid practical joke.
....So actually I don't know if it was simply noise or if he got the perfect conditions to get all sorts of signals. I should have told him that SETI program was still up and any signals may have been "THEM", etc... After all it IS rural Arizona.

wylie

Wed Mar 31 2010, 01:54AM

Registered Member #882 Joined: Sat Jul 07 2007, 04:32AM
Location:
Posts: 103

I should have told him that SETI program was still up and any signals may have been "THEM", etc...

Light reflected off of a thermal air pocket. Swamp Gas would probably be a hard sell.

Steve Conner

Wed Mar 31 2010, 08:33AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

It wouldn't hurt to try an EMI filter in the line to your coil.

Also, does your earth rod do anything? Arizona isn't exactly famous for its damp, highly conductive soil.

Your coil might actually run better and cause less interference if you ran it indoors grounded to your house wiring. (At your own risk!)

Lots of 4hv members (including me) are both hams and Tesla coilers.

radiotech

Wed Mar 31 2010, 05:38PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

If a device produces RFI, it radiates it. If you look at the cables from
old crt monitors and power supplies for laptops, they have ferrite chokes located on the cable as close to the device that is producing the RFI as possible. they look like lumps in the wire. This reduces radiated noise in accordance with FCC limits.

In a word; It de-antennifies the lengh of wire. That said, the question arises what the earth ground is for.

The idea of the ground, apart from safety, on a coil, would be set the set the "earth terminal" at earth potential without radiating any energy.

You might try witchcraft. I have seen issues with sparks jumping across solid steel plates because a bonding braid was left off. However this was on a Cottrell precipator.

previous 1 2

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob