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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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