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#2
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Jim,
Having worked in EMC labs (electromagnetic compatibility), I've heard the signals generated by some equipment. What you fail to understand is that these signals are being modulated at very high rates of speed. Inside of your computer exist a number of oscillators. You assume that only those frequencies and their harmonics would be broadcast. Do yourself a favor and put an HF radio or HF scanner next to your computer while it is on. Turn off the monitor so you won't blame the monitor. Guess what? A ton of garbage. BPL will be worse since it will be carrying more than one signal over the power lines. These will likely carry information at a 1.5 megabaud rate. Check out the ARRL website and view (and listen to) the 26 MB video they have available showing the radio, S-meter, and the car driving around. It is a veritable cacophony of noise all over HF. The fact is that folks such as yourself who are not particularly technically inclined make statements that other non technically inclined individuals will believe without actually studying the matter. I can assure you that your position is totally in error. 73 from Rochester, NY Jim AA2QA " --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.510 / Virus Database: 307 - Release Date: 8/14/03 |
#3
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What you are proposing is to shift the cost of correcting the
interference caused by this technology from those who will profit from it to the victims of the interference. Do you plan to invest your BPL profits into stock in the companys that will manufacture the new radio equipment that your technology will force us all to buy? Steve .. AI7W (Jim Nye) wrote in message ... The claim that BPL will seriously and negatively impact amateur radio is simply fear, uncertainty, and doubt (FUD) spread by the ARRL. That organization needs to justify its existence, and the BPL issue is a convenient way for it to show its activism. The ARRL has apparently followed the path of other self-justifying organizations such as NOW and the NAACP. Unfortunately, the technically unsophisticated do not recognize the difference between coherent and non-coherent noise, and this makes it easy for the ARRL to spread its FUD. But the fact is that, if BPL signals are heard at all, they are coherent (have a predictable phase and amplitude) and therefore can be completely removed at the receiver. This can be done in many ways, most of which amount to nulling the BPL signals by introducing an identical signal which is 180 degrees out of phase with the original. As a matter of fact, most current HF transceivers have what they call a "noise reduction" option already built into them which uses the nulling method to accomplish its goal. Therefore, many amateurs and SWLers already have the needed equipment to deal with any BPL "interference." The ARRL reports have conveniently omitted any mention of the coherency issue, and their measurements are therefore flawed, because they don't reflect real world situations. So take the ARRL claims with a large grain of salt, and don't succumb to the FUD they are spreading. Instead, do some reading on your own by going to non-ARRL web pages such as http://www.uplc.utc.org, and http://www.wave-report.com/tutorials/bpl.htm before accepting the ARRL claims at face value. |
#4
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![]() "Keith" wrote in message .net... Hey don't tell us what you think, tell the FCC with their ECFS. It doesn't matter since NTIA says that BPL is OK NTIA is studying BPL vis a vis USG HF ops ... the same sort of ops that relegated us to 5 spot channels at 5 MHz instead of a band. From talking with the folks there who are looking into it, they seem just as concerned as we should be. Carl - wk3c |
#5
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Jim,
What electric utility do you work for? Or maybe it is the equipment manufacturer that sells the interface devices and equipment to the utility? Where they are testing BPL in Cincinnati, there is S9 noise and you can't get rid of it. Duffy "Jim Nye" wrote in message ... On Tue, 19 Aug 2003 14:47:06 -0000, David Robbins wrote: "Jim Nye" wrote in message ... The claim that BPL will seriously and negatively impact amateur radio is simply fear, uncertainty, and doubt (FUD) spread by the ARRL. That organization needs to justify its existence, and the BPL issue is a convenient way for it to show its activism. The ARRL has apparently followed the path of other self-justifying organizations such as NOW and the NAACP. Unfortunately, the technically unsophisticated do not recognize the difference between coherent and non-coherent noise, and this makes it easy for the ARRL to spread its FUD. But the fact is that, if BPL signals are heard at all, they are coherent (have a predictable phase and amplitude) and therefore can be completely removed at the if they are predictable then they must be constant, if they are constant then they can't carry data, doesn't make much sense to me. You clearly haven't become acquainted with the mathematical definition of "coherent," which doesn't demaind a constant signal at all. What it DOES demand is either a sharply peaked or a periodic autocorrelation function -- properties which enable engineers to come up with predictive filters. receiver. This can be done in many ways, most of which amount to nulling the BPL signals by introducing an identical signal which is 180 degrees out of phase with the original. As a matter of fact, most now, just where do you propose getting this out of phase signal? true, there are devices out there now that can do this, but they are fussy and must be constantly adjusted as you change frequency or switch antennas. and they also have problems with overloading and distortion. current HF transceivers have what they call a "noise reduction" option already built into them which uses the nulling method to accomplish its goal. Therefore, many amateurs and SWLers already have the needed sorry, not with this type of signal. the common noise reduction processors Sorry, but that's not right. The Icom 746PRO for example, has two noise reduction functions, one of which samples slightly out-of-band signals to come up with a time-varying estimate of the values to be subtracted from the in-band signals. There is no need for the signal to be constant with respect to time. The second noise reduction function is directed at impulse noise and is a traditional noise blanker. In any case, you are missing the main point of the original post, and that was that the ARRL FUD conveniently ignores the coherent nature of BPL leakage signals -- a property which makes them far less formidable than the ARRL articles would lead you to believe. |
#6
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I am fortunate that I am far enough from the Emmaus, PA "pilot"
area that PP&L is running (Test Site #3 on Ed Hare's video on the ARRL web page) that I'm not noticing interference here from that small deployment. However, if I go down off the hill into the deployment area, the noise is HORRIBLE throughout the HF bands ... The ARRL is not spreading FUD about Access BPL ... it's the truth and I've heard it for myself. Carl - wk3c "J. D. Beischel" wrote in message ... Jim, What electric utility do you work for? Or maybe it is the equipment manufacturer that sells the interface devices and equipment to the utility? Where they are testing BPL in Cincinnati, there is S9 noise and you can't get rid of it. Duffy "Jim Nye" wrote in message ... On Tue, 19 Aug 2003 14:47:06 -0000, David Robbins wrote: "Jim Nye" wrote in message ... The claim that BPL will seriously and negatively impact amateur radio is simply fear, uncertainty, and doubt (FUD) spread by the ARRL. That organization needs to justify its existence, and the BPL issue is a convenient way for it to show its activism. The ARRL has apparently followed the path of other self-justifying organizations such as NOW and the NAACP. Unfortunately, the technically unsophisticated do not recognize the difference between coherent and non-coherent noise, and this makes it easy for the ARRL to spread its FUD. But the fact is that, if BPL signals are heard at all, they are coherent (have a predictable phase and amplitude) and therefore can be completely removed at the if they are predictable then they must be constant, if they are constant then they can't carry data, doesn't make much sense to me. You clearly haven't become acquainted with the mathematical definition of "coherent," which doesn't demaind a constant signal at all. What it DOES demand is either a sharply peaked or a periodic autocorrelation function -- properties which enable engineers to come up with predictive filters. receiver. This can be done in many ways, most of which amount to nulling the BPL signals by introducing an identical signal which is 180 degrees out of phase with the original. As a matter of fact, most now, just where do you propose getting this out of phase signal? true, there are devices out there now that can do this, but they are fussy and must be constantly adjusted as you change frequency or switch antennas. and they also have problems with overloading and distortion. current HF transceivers have what they call a "noise reduction" option already built into them which uses the nulling method to accomplish its goal. Therefore, many amateurs and SWLers already have the needed sorry, not with this type of signal. the common noise reduction processors Sorry, but that's not right. The Icom 746PRO for example, has two noise reduction functions, one of which samples slightly out-of-band signals to come up with a time-varying estimate of the values to be subtracted from the in-band signals. There is no need for the signal to be constant with respect to time. The second noise reduction function is directed at impulse noise and is a traditional noise blanker. In any case, you are missing the main point of the original post, and that was that the ARRL FUD conveniently ignores the coherent nature of BPL leakage signals -- a property which makes them far less formidable than the ARRL articles would lead you to believe. |
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