electromagnetic field? Concerning discovery....

[Dispatrick]

I've posted here before about ongoing interference around (inside and out) my home and the area around my home/street on both my base radio and my portables that has been going on for many years and I still can't locate a source. Yesterday I took my scanner for a walk up and down my block near the telephone poles and found the interference to possibly be from the telephone pole located next door to me. My concerning discovery is I also noticed the interference to be coming off my metal mailbox in front of my home, an UNPLUGGED strand of decorative summer lights around my deck, and in the rear of my home off an umbrella stand in my yard... Why would these objects be radiating the signal? Is this an electromagnetic field? A ground loop? I'm quite concerned about this and advised my local power company of the pole which possibly may be the source...

 

[bill4long]

an UNPLUGGED strand of decorative summer lights around my deck

Metalic objects can reflect and direct RF with all kinds of interesting and unpredictable results.

Think about it: the directors and reflectors of yagi antennas are not even connected to anything.

 

[dlwtrunked]

I've posted here before about ongoing interference around (inside and out) my home and the area around my home/street on both my base radio and my portables that has been going on for many years and I still can't locate a source. Yesterday I took my scanner for a walk up and down my block near the telephone poles and found the interference to possibly be from the telephone pole located next door to me. My concerning discovery is I also noticed the interference to be coming off my metal mailbox in front of my home, an UNPLUGGED strand of decorative summer lights around my deck, and in the rear of my home off an umbrella stand in my yard... Why would these objects be radiating the signal? Is this an electromagnetic field? A ground loop? I'm quite concerned about this and advised my local power company of the pole which possibly may be the source...

Essentially... bringing your radio near those objects allowed them to act like a larger antenna. This gave your radio greater sensitivity and can also overload it into allowing it to receive frequencies to which it is not actually tuned. Once in N Ontario years ago, I brought a transistor radio near wiring to see if I could improve reception. I heard lots of things, mostly not even on the frequency to which the radio was tuned. The first thing to do to try to find interferency is to pull the master fuses on your own home and listen with a transistor radio. Much of the time, that will lead to the end of your hunt.

But you say scanner interference, which is a little different. Interference on scanners is rarer than on lower frequencies. You need to tell us the mode (AM or FM), the frequency, and what it sounds like.

 

[krokus]

Why would these objects be radiating the signal? Is this an electromagnetic field?

Are these LED lights, or have a DC power supply? If so, then you have intermodulation interference, which is called IMI. Diodes mix radio signals, and mix the results of that mix with the original signals and other products of mixing, which are called product orders. These signals decrease in strength, the further down the mix matrix they are.

 

[MUTNAV]

I'm not suggesting that you do this, but what I would do is.....

1. Take appropriate precautions against electrocution in case something is wired wrong.

2. Take my multi-meter (set to AC volts) and measure if there is voltage between the chassis of a piece of outdoor equipment that isn't plugged in (maybe the umbrella stand), and the actual ground (a few feet away, using a, screwdriver poked into the ground).

As in, I would take a piece of bare wire, wrap it around a screwdriver blade and one lead of my multi-meter, connect the other lead to your umbrella stand (where there is no paint or insulation).

If there is any voltage, I'd call an electrician.

I've had part of the problem that you've had with the electricity before (in other countries) where even though the hot lead was wired to ground, there wasn't enough to trip a circuit breaker.

Please let us know what happens if you decide to try this.
Thanks
Joel

 

[Motoballa]

We've had this happen many times where I live, especially on a local repeater where one of the LED light poles goes crazy or a nearby power pole. We contact our city and they will investigate and fix the pole in question within about a week and the interference stops.

If you can for sure tell its the pole then contact your cities electrical company or the city itself and they can send someone out to fix it.

 

[Dispatrick]

It's on my scanners in the VHF band FM Mode. Significant in the lower VHF and it sounds like an open carrier on the affected frequencies.

Here are some of the freq's affected in case anyone hears the noise in and or around their home in FM mode it'll sound like an open carrier. 33.4500 seems to be the STRONGEST signal.

28.320
28.440
28.500
28.560
29.480
29.910
29.970
30.580
30.640
32.900
33.330
33.450 STRONG
33.970
34.060
34.120
34.300
34.580
34.610
34.640
34.670
34.730
35.220
35.250
35.340
37.730
39.250
39.680
40.350
43.770
43.830
47.040 STRONG
47.800
48.410
48.470

 

[a417]

I highly doubt a portable umbrella stand is connected to the mains. If it's like every other deck umbrella stand I can think of, pretty sure you can not worry about the possibility of being electrocuted...maybe if it was one of those with the giant lawn dart at the bottom, any MAYBE if it was in an area where they use SWER...but I don't think they use it in the dirty Jerz.

I'm with @bill4long.

 

[MUTNAV]

I highly doubt a portable umbrella stand is connected to the mains.

With a hot conductor going to ground, a gradient could exist. There is no problem with just checking if there is a voltage on it, and then he never have to go back to the idea.

Thanks
Joel