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Have you heard about this?

Sven

Well-known member
Inter-Bloody-ference!

A pain in the ear

BY JONATHAN PORTER

I
 
Thats intresting , thanks for sharing that ,
 
So, while I'm driving down the road in my car and the radio signal drops then it comes back its because the wind changes :unsure:
Last time I checked radio waves or fields of energy are not made up of any solid matter.
Lets say if a couple of people are using a set of walkie talkies and at a good distance, but they are in a strong wind, would that mean that only the one that's down wind can receive a audible signal?

EMI is not like pollen blowing around in the wind, your either in the field or not, now it can be bounced or reflected off from certain things.

Mark
 
Mark, you said "fields of energy are not made up of any solid matter" even though you are correct in saying that in the area of electromagnetic propagation I'm not sure it applies in the way you think it does. You also said..... " it can be bounced or reflected off from certain things " that is true also, but you are forgetting bending it or refraction.

Light also holds no mass and is not solid matter yet we all know that it can bend when encountering different density of material. Light is also considered an electromagnetic wave so according to you it should only "bounced or reflected from certain things" and not be affected by wind. Atmospheric disturbance is what causes stars to appear to twinkle. That is light being affected by the atmosphere, atmosphere = wind my friend.

Back to radiowaves.... Radiowaves are the same as light in being electro magnetic wave albeit much longer in wavelength. Being longer in wavelength it is less prone to interference. A 14khz electromagnetic wave will penetrate earth while a 400thz electromagnetic wave (light) will be blocked by a single leaf. Having said that, the atmosphere, wind, also affects radiowaves albeit to a lesser degree than light. Read up on propagation and refraction of radiowaves here http://www.mike-willis.com/Tutorial/PF6.htm

Now, what is being discussed was eletro magnetic interference. Having established that wind to varying degrees can affect radiowaves, interference is a whole different level of complication. Wind can cause interference in many, perhaps countless ways. Maybe it affects the propagation of the radiowave itself directly (speculation) in that it's area of effect shifts slightly with wind variance. I agree with you that this is unlikely (in this narrow scope) but disagree with you that it's impossible. The effects are there, very measurable (in larger scope) and any shortwave guy will enlighten you as to atmospheric events affecting who you can talk to and when via shortwave. Wind can affect things other than the radiowave itself and cause even greater interference. How about more speculation.... Wind affecting powerlines in that with wind they sway slightly. This affects the relationship of one powerline to another that in turn affects attenuation (signal loss). The field emitted by those powerlines will shift in turn it's area of effect will shift. So, on a calm windless day the interference caused by powerlines for conversations sake extends 300 yards from the powerlines. On a windy day the powerlines shifts randomly, therefore the field and area of effect of the interference can become 200-400 yards and continues to shift as long as wind happens. This speculation is based on the relationship of one powerline to another and it's emitted field.

Another possibility is grounding or isolation. High tension powerlines are isolated from ground but that isolation is not perfect. Leakage is unavoidable and the leakage from the cable to the tower keeping it up is substantial. That leakage are from cables that hold 10,000+ volts and tens of thousands of amps. Those leakages can come from the insulators, a tree that's too close, dust, a bird sitting on the cable, the possibilities are countless. So the strength and frequency, lobe shape, etc of the field that is causing interference is just as countless and just as random.

So, what I'm getting at is the possibilities of interference is incredibly complicated and can come from countless ways and sources. Wind affects the radiowave/field itself (admittedly minorly) but wind can and do affect just about anything else in our world that does emit radiowaves and cause interference. One calm day on one spot on the ground interference does NOT happen. Wind picks up and the same spot interference does happen. Not only is this plausible, but it is foolhardy to automatically say wind cannot affect interference based on a single and wrong assumption that radiowaves being massless cannot be affected by wind therefore interference cannot be affected by wind.

P.S. Just a disclaimer, I'm just a regular lay person and what I've said are just my personal understandings and I could be COMPLETELY off the mark so take it with a lump of salt. :)
 
Well, many of the stars are at lest millions of light years away and many of them have been gone for maybe thousands of years already, lets bring it back down to earth a bit.

Power lines might be fifty feet or so overhead, the EMI energy produced from those lines radiate outward as a surrounding field and if your under them or near them the wind isn't going to blow it away so you can metal detect under them, which is a little bit different than light from a star flickering from 100 million light years away.

No, you do not really bend RF, it bounces, at lest in areas reasonably close to the earth surface.
Now what your talking about with radio waves is called "Propagation" and then the signal isn't really bent, its still bounced, but it has to reach into at lest the lower level of the ionosphere. CB'ers called it talking "skip" because the signal goes up, bounces back down hundreds or even thousands of miles away and much of the range in between is "Skipped" This type of activity is well above the normal ground levels were really talking about anyway.
Now, I never used the term "Impossible" you did. What I was saying is that Fields of energy like EMI or RF doesn't blow around like "Pollen" meaning that if your under or very near power lines the wind isn't going to blow the EMI away from you.

And, my old HAM call sign was KC8-DCV but I didn't stay with the hobby for long and I let my license expire years ago.

Mark
 
Eh, maybe we're splitting hairs so I'll address the main discussion, wind affecting interference. I do agree that wind does not blow a field around like smoke but wind can still affect the field in every other way. I used the example of powerlines swaying from wind. That movement can affect the field in countless ways. The person on the ground can notice that as interference happens when the wind is blowing or that the interference shifts when the wind is blowing.

So, someone noticing that there could be a correlation between wind and interference is entirely plausible. Let me apply this to Jonathan porter's example..... No wind there is a piece of metal close to the power cable and has a strong leakage causing interference. A strong wind picks up in the proper direction and it blows the cable further away from that piece of metal causing leakage to be reduced. Wind slows down the cable shifts back to being close and leakage and interference goes up again. Someone might think it's the field being blown around, but in reality it's the field size that shifts because of wind affecting the cables.

I'm just saying that until you are able to understand the situation better, don't be so quick to dismiss someone's observations. Unless the person is completely fabricating it, it was observed, maybe not understood but at least observed.

Now as to why my rather long winded post, what prompted that was this "Last time I checked radio waves or fields of energy are not made up of any solid matter" seemingly insinuating that because radiowaves are not solid matter it cannot be affected by wind or atmosphere. I merely addressed that it is not the case.

Anyways, we seem to be in agreement on most things but just addressing different points. Your post just seemed too quick to be dismissive and more than anything else that was what I was addressing. Wow, it's late for me and I want to hit the totlot tomorrow before it's filled with kids. Catch you another time.
 
Its quite possible the wind is blowing the power lines enough to distort the field of energy and make it appear as if the wind is blowing the RF energy downwind (If the story is even true).
I'm with MarkCZ, wind will not have an affect RF energy.
 
The wind does not move the EMI feild, BUT there exist a value of inductance and capcitance between the high tension lines. This is a know issue and does cause current and voltage lead/lag issues for power companies. With the lines stationary this is a fixed value and easily dealt with. When the wind blows, the lines are moving and the values of inductance and capacitance will change between the lines, and this could possibly effect the EMI field and it's shape. I know for a fact it will effect capacitve and inductive values, and that will have some effect. To what extent and to how it may change the shape of the EMI feild I am not sure, but it will have some effect. It seems that this might be a plausible explanation.
 
Rainyday101 said:
The wind does not move the EMI feild, BUT there exist a value of inductance and capcitance between the high tension lines. This is a know issue and does cause current and voltage lead/lag issues for power companies. With the lines stationary this is a fixed value and easily dealt with. When the wind blows, the lines are moving and the values of inductance and capacitance will change between the lines, and this could possibly effect the EMI field and it's shape. I know for a fact it will effect capacitve and inductive values, and that will have some effect. To what extent and to how it may change the shape of the EMI feild I am not sure, but it will have some effect. It seems that this might be a plausible explanation.

Yes, it would change the values, but the lines moving could be more of a problem metal detecting around them to due to inconsistencies in the energy field (more like an oscillation effect to the detector's electronics) , it could have more of an in and out effect making adjustments for such inconsistencies really difficult.

Now the best option I see in these areas would be,
Smaller Coils,
Lower sensitivity and reduced gain settings,
Hunt when the power demands are at the lowest times, like late night, early spring, or mid fall. if the load on the lines are reduced it may have an effect on reducing the EMI around them a little.

Mark
 
Rainyday101 said:
The wind does not move the EMI feild, BUT there exist a value of inductance and capcitance between the high tension lines. This is a know issue and does cause current and voltage lead/lag issues for power companies. With the lines stationary this is a fixed value and easily dealt with. When the wind blows, the lines are moving and the values of inductance and capacitance will change between the lines, and this could possibly effect the EMI field and it's shape. I know for a fact it will effect capacitve and inductive values, and that will have some effect. To what extent and to how it may change the shape of the EMI feild I am not sure, but it will have some effect. It seems that this might be a plausible explanation.

Someone that understands my point, fantastic! But really my ultimate point is that none of us reading about it was there. Even the person that was did not have proper equipment to gather enough information to understand what happened. The LAST thing anybody can do is to make an absolute statement. Especially those of us that are only reading about it on the net. Which is absolutely all of us. The person that wrote the article is not involved at all in this thread, only someone pointing to that article. We can only speculate at the very best.
 
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