Bpl

[SCPD]

Maybe if I post in here, the radio police won't jump all over me with the legality of my question. I don't care if what I'm asking is legal; I just want to know if it will work:

As many know, BPL, which in a nutshell is high speed data over the power lines, has been kicked around for many years. The ARRL is opposed to it, saying it can interfere with HF ham radio.

Well, for a while, I’ve been wondering about something. I've been looking at BPL equipment on the ‘net, perusing the manufacturer’s equipment descriptions, theory of operation, etc. How it basically works is that there are high frequency components riding on the 60 hertz in the power lines coming into your home.

So let’s say BPL was introduced in my neighborhood. And I start getting interference on the low bands. My question is this: Am I missing something when I think I can just make a low pass filter, (say 1Khz) and plug it into the duplex receptacle in my home, and send all the high frequency components to ground?

Someone tell me the error of my thinking. Once again, I don’t care about the legalities of this; we are just talking technology here.

 

[N_Jay]

Hu?

I would worry more about the legalities, since you don't seem to understand the technology.:twisted:

 

[gewecke]

The L.p.filter is a good idea if it was broad enough to cover the amount of spectrum you're wanting to use? You would probably have to have more than one depending on the bands you prefer.
That's the nice things about the spectrum above 50mhz. No bpl.
N9ZAS.

 

[N_Jay]

Except it seems that he thinks if you put a low pass filer across your line you can somehow shunt all the BPL signal energy to ground. Go Figger?

 

[gewecke]

Right,but in his research I'm sure he'll learn the science behind BPL if he hasn't already?
I'm optimistic,he'll figure out what he needs to here.
N9ZAS.

 

[N_Jay]

Right,but in his research I'm sure he'll learn the science behind BPL if he hasn't already?
I'm optimistic,he'll figure out what he needs to here.
N9ZAS.

Oh, you starry eyed dreamer, you. :twisted:

 

[gewecke]

I don't dream much njay. But I will give people the benefit of the doubt.
N9ZAS.

 

[poltergeisty]

In other words, does it look like his radio is plugged into any outlet???

YouTube - Broadband over Powerlines - A Radio Amateur's Perspective


Hope this crap isn't used in hurricane prone areas...

 

[gewecke]

Well where that footage was taken if the QRM doesn't get ya,then the pot holes in that road will!
N9ZAS.

 

[SCPD]

BPL over powerlines

Well where that footage was taken if the QRM doesn't get ya,then the pot holes in that road will!
N9ZAS.

I suppose I need to concede the point that my theory would not work with mobile HF. The biggest problem with that video is that he is driving on the wrong side of the road. hahaha.

One of the best selling BPL modems is made by Mitsubishi. Here is a link to a 8 page pdf about their system. As the link show, the modems plug right into the homes AC outlets to recover the high speed component. Looking at this, I still think that, if BPL was used by my local utility, a low pass filter, plugged into my AC outlet, would bring down the high speed component in the neighborhood. And for review, a low pass filter passes all frequencies below a certain freq, and blocks all freqs above a certain freq. So a 1khz filter would short all frequencies above 1khz to ground.

Thoughts?
Once again, just thoughts and comments on if you think it would work or not, I realize it would not be legal if it worked.

http://www.ieee802.org/802_tutorials/04-March/plc-PLC_Mitsubish_mjs.pdf

 

[N_Jay]

You are thinking of the power transmission system as if it was a DC circuit with near zero reactive components.

In effect what you have is a set of interconnected transmission lines. Even if your "Low pas filter was a perfect short circuit, it would be reflected as different impedances at different frequencies at different points in the network.

Most BPL to the home only goes as far as the first transformer before it is picked off by an active device. So at best you might cripple a few of the users on your transformer, but no further.

From my understanding the modems use several frequency sets and actively adapt to find frequency sets that maximize throughput. More reason why your "thought" is a little impractical.

 

[kb2vxa]

Forget the reactive components between your ears, have you overlooked the fact that some antenna radiator elements are GROUNDED? Stamp out confusion, KISS!

 

[SCPD]

Hmmmm

You are thinking of the power transmission system as if it was a DC circuit with near zero reactive components.

In effect what you have is a set of interconnected transmission lines. Even if your "Low pas filter was a perfect short circuit, it would be reflected as different impedances at different frequencies at different points in the network.

Most BPL to the home only goes as far as the first transformer before it is picked off by an active device. So at best you might cripple a few of the users on your transformer, but no further.

From my understanding the modems use several frequency sets and actively adapt to find frequency sets that maximize throughput. More reason why your "thought" is a little impractical.

Njay:

The statement you make that "most BPL only goes as far as the pole" intrigues me. Can you give me some manufacturer names where the high frequency portion of the BPL rides on the 60 hz only as far as the pole? Like I said in my original post, I have been "putzing" around researching this for a few years now. And of the five systems I have looked at, the “data” portion of the BPL comes all the way to the home's duplex plugs. After I read your response a few days ago, I spent even more time looking around, and asking around trying to find a system where the BPL stops at the pole.

And I also feel you haven’t given me a satisfactory explanation as to why the 1Khz low pass filter would not work. Regardless of what you call it, reactance, impedance, FSK, whatever, there is still a frequency component to the signal. Please explain further why a low pass filter would not take everything above 1 kilohertz to ground. I agree completely when you say that the modems use several different frequency sets. But all those frequency sets are above 1 MHz. Like I said in a previous post, the purpose of a low pass filter is to block all frequencies above the cut off frequency. No matter what you call them, they are still signals that are changing from a negative to a positive value greater than 1000 times a second.

While your response may be correct, it’s still unclear to me.
.

 

[kb2vxa]

It will be forever unclear unless you get a little basic theory under your belt. The long and the short of it is you don't even understand the meaning of the term, so how can anyone explain how a filter works when you don't know what a filter IS? Please learn to speak our language, then we can communicate.

 

[SCPD]

The Spirit of Two Land.

It will be forever unclear unless you get a little basic theory under your belt. The long and the short of it is you don't even understand the meaning of the term, so how can anyone explain how a filter works when you don't know what a filter IS? Please learn to speak our language, then we can communicate.

All three of my posts have been polite inquiries as to why it would not work. I haven't flamed anyone, I haven’t come back with curt little smart aleck remarks. I've been very upbeat, simply trying to satisfy my curiosity.

Yet the response I have been getting back from you is vindictive, mean, and don't even come close to answering the question. That's all right, I'll leave it alone. I see you have a ham call. It's so heartwarming to see you living up to The Amateur's Code, especially the FRIENDLY part.

The Amateur's Code
The Radio Amateur is

CONSIDERATE...never knowingly operates in such a way as to lessen the pleasure of others.

LOYAL...offers loyalty, encouragement and support to other amateurs, local clubs, and the American Radio Relay League, through which Amateur Radio in the United States is represented nationally and internationally.

PROGRESSIVE...with knowledge abreast of science, a well-built and efficient station and operation above reproach.

FRIENDLY...slow and patient operating when requested; friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit.

BALANCED...radio is an avocation, never interfering with duties owed to family, job, school or community.

PATRIOTIC...station and skill always ready for service to country and community.

 

[zz0468]

And for review, a low pass filter passes all frequencies below a certain freq, and blocks all freqs above a certain freq. So a 1khz filter would short all frequencies above 1khz to gnd.

Thoughts?
Once again, just thoughts and comments on if you think it would work or not, I realize it would not be legal if it worked.

At best, it would serve to keep your BPL modem from working. All that energy leaking from the overhead power lines would continue to leak, regardless of anything you plug into your outlet.

Now, if you put your filter at the output of the BPL device where it applies it's energy to the power line, THAT would be a step in the right direction.