Topic: Interference: Red: Solved??

[Cutty Sark Sailor]

1. Sporadic external interference, various, especially during dark hours. (street lighting, truck axle factory 1500' south, unknowns).
2. Line Freq and line harmonic interference.
3. What appears to be Controller radiation.
4. Computer interference.

Was going to test a couple more days, but I'm satisfied after 18 hours.
Plagued with the first 3 types of noise, and after chasing all over for sources, I had a flash of insight that may effect others.

My home has outer wall foil-covered foam insulation panels.
My amp assy was on garage shelf on outer walls.
My controller mounted on external wall 25' (8m) away.

The insulating structure appears to be re-radiating both external and internal sources.

With the amp moved to the center of the garage the external sources have been minimized. There are still some line freq/harmonics, but that appears diminished also. The controller noise also appears reduced. (The computer noise is easily resolved by distance from machines, in my case, and has been minimized since day one.)

I have not moved the controller from the exterior wall, but that's going to happen!
It appears that the amp and antennas need to be 6-10 feet (2-3m) from any outside wall... the further the better.
In my case, the amp needs to be as far as possible from the electrical panel, which is 4 feet from the external wall.

While I need to do some more exploration on this, including possible other sources internally that are near exterior walls, I felt it should be passed on.

Cheers!
Mike

[miraculon]

Interesting. I wonder if this is a reflected standing wave of some kind.
It might be setting up nodes/anti-nodes that re-enforce/cancel in various locations.
Maybe you need to line your walls with ferrite tiles. 

Greg H.

[Cutty Sark Sailor]

Interesting. I wonder if this is a reflected standing wave of some kind.
It might be setting up nodes/anti-nodes that re-enforce/cancel in various locations.
Maybe you need to line your walls with ferrite tiles.  

Greg H.

Is interesting, isn't it?  A few feet either way produces variations!  One 'sweet spot'... is about 5 ft back from the garage door, about 5 feet wide and 3 feet deep parallel to the door, and about half of the door's height... peculiar... .
I do have a 'bag o' beads', but none big enough to fit around the house,

[DaleReid]

sort of like finding the one small cubic foot in a remote motel where you get cell service while on a trip.

The frequencies here, however, are at widely differing ends of the spectrum.  I'd think the aluminized foam would have made a sort of faraday cage, or maybe it isn't grounded.

Has anyone had experience with metal siding vs. wood, vs. vinyl on the structure enclosing the antenna?  Just curious so as to be alert if others in the future run into a perplexing problem, it might be something to suggest if the one with trouble hadn't thought of that.

I think a radome made from a garbage can for out of doors placement was in one of the other threads.

[Cutty Sark Sailor]

Actually, a .22 long or two into a few street lights, and a torch to a truck axle factory over the hill would probably solve 75% of the issues.

[dfroula]

Before finding a location in the house to place my Red amplifier, I used an old telephone testing device I had. The device is used by telephone installers to locate a specific pair of wires on a telephone terminal block with lots of pairs of connections.

The telephone guy connected a beeper box that generated a high-amplitude beeping to the two phone wires in the house. He would take the second device and move its probe near the terminal contacts in the junction box until the beeping was the loudest, identifying where the house pair was connected.

The probe is simply a very high-gain, high impedance audio amp with a short probe antenna on the end.

I had a couple of the probes in my junk box. I clipped a longer piece of wire to the probe. The thing picks up 60 Hz power hum and other capacitively coupled noise sources as one walks around the house. There were some areas of the house that were extremely noisy, while just a few feet away the 60 Hz noise dropped to nothing. Some parts of the house had weird unexplained whining noises where no electronic equipment was around for 25 feet or more. Weird. It also picks up nearby lightning!

You could probably make one easily. The circuit had a 9 volt battery and simple FET input op-amp inside connected for very high voltage gain.

My daughter also had an EMF "ghost detector" meter with an LED bar graph that I tried as well. The paranormal investigators on the "Ghost Hunters" TV show use it to supposedly detect the presence of departed spirits. That worked as well, except the audio amp probe had the advantage of being able to hear the offending signal.

...not that I'm suggesting supernatural origins of your noise source!

Best,

Don

[miraculon]

Don,

I like the toner idea. I have one and didn't think of using that. I'll give that a try.

I have had some luck with Cutty's AM radio method. My Ethernet cables to the outdoor webcam are hot with noise on low AM. Tried some clamp-on ferrites with mixed results.

I have an EMF meter: a Coronet ED78 http://www.norad4u.com/monitor/home-emr-meters#TOC-CORNET-ED78G-S. I thought that I "had something" with the H-field sensor, but couldn't positively nail it down.

Chasing the noises is like peeling an onion. Whenever I think that "this is it" and put a countermeasure on it, some other noise pops up whack-a-mole style 

I have been pondering using two ferrite rod antennas (mounted in the PVC ell) and feed it into some kind of high-gain stereo amp, one channel per rod.

Greg H.

[Cutty Sark Sailor]

Actually, this dwelling is so sensitive, I was thinking about 2 turns of 8 ga wire around the perimeter and making the next generation antenna system...  
...now to find a similar home nearby for ant B... then worry about selectivity.

[dfroula]

That reminds of a project I tried as a kid. I read you could run a single wire loop around a room perimeter and wire the two ends of the loop to the speaker output of a hi-fi amp. A simple receiver was made with a Radio Shack (well, Allied Electronics then) telephone inductive pickup coil connected to a battery powered amp. The pickup would detect the music anywhere inside the loop. It worked pretty well.

Don

Actually, this dwelling is so sensitive, I was thinking about 2 turns of 8 ga wire around the perimeter and making the next generation antenna system...  
...now to find a similar home nearby for ant B... then worry about selectivity.

[miraculon]

Don,

I like the toner idea. I have one and didn't think of using that. I'll give that a try.

I have had some luck with Cutty's AM radio method. My Ethernet cables to the outdoor webcam are hot with noise on low AM. Tried some clamp-on ferrites with mixed results.

I have an EMF meter: a Coronet ED78 http://www.norad4u.com/monitor/home-emr-meters#TOC-CORNET-ED78G-S. I thought that I "had something" with the H-field sensor, but couldn't positively nail it down.

Chasing the noises is like peeling an onion. Whenever I think that "this is it" and put a countermeasure on it, some other noise pops up whack-a-mole style 

I have been pondering using two ferrite rod antennas (mounted in the PVC ell) and feed it into some kind of high-gain stereo amp, one channel per rod.

Greg H.

Well, the toner identified all kinds of new noise sources. Unfortunately, none of them was the "culprit" that was causing the interference mode. This seems to be the case with every sniffer/sensor I use. I find noises, but they are not the one that is causing my actual problem. 

Greg H.