rf_engineer
join:2003-08-04
USA
| Re: Sounds like a annoyed HAM op. said by PDXPLT  :said by rf_engineer :BPL has no wireless spectrum to stay in - it's a wired network therefore it has no frequency allocations....just like cable and DSL which deliver broadband just fine without wrecking spectrum. Well, that's close but not quite true. Licensed services in a portion of spectrum have primary allocations or secondary allocations, but they are rarely exclusive (some of the radio astronomy bands probably being the only ones). Licensed-exempt users under Part 15 are the bottom of the totem pole, but they are explicitly permitted under Part 15 to radiate RF power in certain bands as an intentional, unintentional, or incidental radiator. This can even lead to some degree of interference, so long as such interference does not lead to the level of "harmful" (that's why those electric drills can remain on the market), and in addition, the license-exempt user must accept harmful interference from any source. What you're saying is true, but it doesn't have any bearing on my original statement. BPL has no wireless frequency allocations. Maybe this is just a discussion of semantics, but being allowed to intentionally or unintentionally emit radiation does not constitute a frequency allocation. Most people would consider a primary or secondary frequency allocation, a frequency allocation....as the name would suggest. The context of my response was to a poster that implied ham radio and BPL should stay on their own frequencies. BPL has no such frequencies.
I know ARRL lawyers disagree with this portion of the law, and argue in nearly all of their filings with the FCC that the Commission has no authority to authorize Part 15 operation in the first place. But they've been trying for over 25 years to win that point, and haven't done so yet (I suppose that's why the position the ARRL takes in press releases to the public and their membership is a much more reasonable one than this official position they take in the FCC filings. Or maybe they have no idea what their lawyers are doing). You or someone claimed this here before and I asked for some quote or something to support this, but I haven't seen anything. The ARRL has questioned the FCC's ability to allow BPL under Part 15 as the rules were clearly never written with broadband large geographical emitters in mind, but never their authority to authorize Part 15 devices. That would be just plain stupid, since every piece of electronics gear in the US and even ham radio equipment is allowed to exist under Part 15. The ARRL's public and FCC filing positions are the same -- in every news article they link to PDFs of their filings, and it's available via the FCC ECFS to the general public, so I'm not sure how they could pull off such a ruse as you would suggest. It's foolhardy to think ARRL management would spend money on lawyers not representing core ARRL positions on issues when there's thousands of dues-paying members that read all their filings. Again, please quote something from an ARRL filing that supports your statement, otherwise I call you-know-what 
BTW, UTP telephone wring is not perfectly balanced, and radiates some as well. With the rollout of VDSL expecially, there was concern about harmful interference in the HF band. Unlike much of the BPL community, however, the DSL community took up the issue head-on, and did technical analyses and field measurements that ulimately resulted in the ham bands being notched out of the VDSL spectrum. Leaky coax cable systems are also frequently an issue. Agreed, but UTP wiring and even leaky cable systems are much better off with regards to radiation that BPL can ever be.
Bottom line is that it's too bad that these idiot BPL operators in Virginia decided to try to use PR rather than engineering to deal with the issue, and ended up giving all BPL a bad name. It's too bad that the BPL technology supplier used for most of the BPL trials in the U.S. also didn't care about interference. But if you look at Cincinnati, where Current Technologies has been operating for quite some time, hams are OK, airplanes aren't falling out of the sky, and emergency communications services work just fine. So apparently there is a technical solution to these issues, if the willingness to implement it is there, along with the required engineering expertice.
I agree this can be made to work, although it's somewhat of a false solution. Someone's spectrum is getting trashed when a BPL system is in operation. Notching just moves it away from the squeaky wheel. Manassas isn't the first system to give BPL a bad name, though it's the most recent. |
