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RFI caused by BPL soon resolved ?
Hi,
Do you remember the problem caused by broadcasting tests via the power line ? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... http://www.arrl.org/news/stories/2003/10/09/1/?nc=1 Thierry ON4SKY, LX3SKY http://www.astrosurf.com/lombry/menu-qsl/.htm "Thierry" see my website a écrit dans le message de ... Internet trials using the electricity power cabling sytem are currently undertaken in the USA and european countries like Austria, Belgium, France, Germany, Luxembourg and Switzerland among others by private and national electricity companies. Such trials are in violation of the european directive about the "electromagnetic compatibility" (ref. 92/31/EEC handling the famous CE logo) that states that "everybody has the right to use the frequencies at the condition to not bother the other users". However, it appears that these private or national companies are far to respect this law. Amateur radio is a service that we pay yearly and as such, if we can not practice this activity we should have the right to require an exploitation losse. Unfortunately neither our national representative ham associations (DARC, UBA, REF, RSGB, etc) nor the concerned IARU delegation can oppose to this criminal practice. Ham associations have discussed about this problem in the offices of the European Commission at Brussels, but without to get the slightest action or result up to day... Confronted to such laxities and to lobbies that are standing by, recently Hilary, alias G4JKS gave up his fight against administrations, hence the publication of this article that the author ask us to publish as often as possible on the Internet. The right technology for the right job, by Peter Cochrane, http://www.silicon.com/petercochrane This document is a reprint from a short article published on Silicon website in which the author reminded how can be hard the fight against administrations even when hams rights are derided. Here are his commentaries. For a decade now business plans have arrived on my desk, in increasing numbers each year, but only a small percentage find their way to commercial success. Remarkably I see very little correlation between plans. There is, however, a major exception where the same plan seems to arrive on my desk every year. Each time it is presented as revolutionary and ground-breaking. But it is always the same technology and it is always as flawed and as misconceived as the original I first saw a decade ago. News reports often included to amplify the case are along the following lines : XYZ Company is proud to report broadband internet trials are underway using a ground-breaking technology that will revolutionise radio, TV, cable TV, internet and data services to the home. Existing electricity power cable can supply all of your digital services at speeds up to 50 Mbits. Extensive laboratory trials have proven this technology, and testing with customers is at an early stage. If fully successful a commercial rollout is planned within the next three months. It is then customary to include a CEO interview that says something along the lines of : "All the obstacles have been overcome. The technology is now proven, stable and economically viable, and we are in a position to revolutionise the last mile. We also predict this technology will see the demise of the telco in the next decade..." Partner companies usually keep their names secret in anticipation of further announcements to be made later that year and the technical press always seem convinced it is all true. But about 6-12 months after the announcements the companies involved quietly say they are ceasing trials and development because some alternative technology has been discovered. It then goes very quiet and nothing more is heard. I wouldn't find this so upsetting if it only happened once but to my knowledge there have been dozens of false dawns. If only the people involved would visit my office I could save them a small fortune. At a modest estimate, over $200m has been expended to date and no one has been successful in transmitting significant amounts of data over power cables to the home. I can guarantee no one will get this technology to work as advertised. It might be appealing and economically attractive but I'm afraid the basic laws of physics cannot be sidelined. For anyone contemplating the waste of another $5-30m here is my 'don't do it' shortlist: - Power cables employ low-grade plastic that is unfriendly to high-frequency signals as the absorption per unit length is very high. This alone precludes transmission of high-speed data over significant distances. - Power cables are not physically symmetrical and are therefore very effective antennas. They radiate energy from high-speed data signals which becomes a source of interference for wireless services including broadcast radio as well as emergency, maritime, aeronautical, military and navigation services. By reciprocity they also suck in energy from every local radio source which further degrades data signals. - As signals propagate along cables they become weaker but the switching transients from washings machines, refrigerators, vacuum cleaners, electric drills, light switches and other appliances are huge, do not decay at the same rate and swamp data signals. - Switching transients on power grids with generators going on and off line, dynamic load sharing, fault and maintenance work, all induces massive transients that also swamp data signals. - Cable joints, transformers, power meters, the on/off nature of electrical appliances and the topology of power grids create large load changes and multiple signal reflection points. This creates a dynamic echo environment where the transmitted signal is further corrupted. - Real time communications of any kind - whether by telephone, radio or TV - are taken out by the huge voltage transients inherent to power lines and ultimately the data rates achievable for non-real time are also very low. - Transformers and power meters require a workaround as they present an absolute block to any high frequency signals. This is a short disaster list that says this technology will not work. And the real nail in the coffin? Telephone and cables were designed to carry far higher frequencies than 50Hz power cables and in every aspect offer superior performance for all data applications. And more recently wireless technology is becoming so low cost and so high performance that signal processing requirements for data over power cables, even if it were possible, would be prohibitively expensive in comparison. In many locations the power companies have installed optical fibre along their power lines for telemetry related to the control of power distribution. Because their data requirements are so meagre huge amounts of bandwidth are available. So it does make sense for wireless technology to be used at that end point, in a distribution mode to attack the last mile. Despite all of this there are more than 20 power companies currently active across Europe planning or conducting trials. The reported field performance results are very poor, as expected! Installation costs are higher than the telcos and cablecos. Yet they still seem determined to become the biggest source of radio interference on the planet. And the ultimate decider? It looks as though the politicians will be asked to decide between the power and wireless lobbies on the legality of the interference levels. Contrary to a widely held belief, all the technology necessary to transform the local loop is to hand, and sporadic solutions such as data over powerline are a bit of an economically driven red herring. So please, will the next candidate thinking of sending me another business plan with a revolutionary technology that will exploit power cables please employ someone who understands Maxwell's equations, data transmission and holistic economics. This column was compiled in a hotel lobby between meetings and despatched via a Wi-Fi link that appeared without identification - thanks to whoever decided to provide this charitable service. |
"Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
This may be true.
But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. AK wrote: "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
This may be true.
But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. AK wrote: "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"Bill" wrote in message ... This may be true. But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. Maybe these political are reading this post, I hope. In all cases we all hope that the ITU WP 6E's report will be in favor of spectrum users without modifying our rights to use amateur bands as we already observed in UHF, 1.2 and 2.4 GHz some years ago, that were partly reassigned.... Thierry ON4SKY, LX3SKY http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm AK wrote: "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"Bill" wrote in message ... This may be true. But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. Maybe these political are reading this post, I hope. In all cases we all hope that the ITU WP 6E's report will be in favor of spectrum users without modifying our rights to use amateur bands as we already observed in UHF, 1.2 and 2.4 GHz some years ago, that were partly reassigned.... Thierry ON4SKY, LX3SKY http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm AK wrote: "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"AK" wrote in message news:mTkkb.810947$YN5.819762@sccrnsc01... "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? Correct. The best solution to ensure our defense should be to have in our camp a Congressist and OM (like K4TPJ and others) or a big spectrum user (like K6EWP directing the US Strategic Command) who could speak for us all. It should be interesting to get their opinion. Affair to be followed. Thierry ON4SKY http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"AK" wrote in message news:mTkkb.810947$YN5.819762@sccrnsc01... "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? Correct. The best solution to ensure our defense should be to have in our camp a Congressist and OM (like K4TPJ and others) or a big spectrum user (like K6EWP directing the US Strategic Command) who could speak for us all. It should be interesting to get their opinion. Affair to be followed. Thierry ON4SKY http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ |
"Walt Davidson" wrote in message ... On Sun, 19 Oct 2003 06:13:16 -0400, Bill wrote: But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. That didn't seem to stop the USA going its own way earlier this year, contrary to the wishes of the UN. Indeed and lobbying are often link to financial interests. Noone broadcaster (and still less with the future DRM, the digital AM) will never accept that its spectrum be reduced but the one of hams could be... There is maybe one way to fight against a potential reduction of our bands or increasing of the noise level. A good way to make the pressure on ITU in order that they protect our rights, IMHO, should be to request the help of some famous people. There are so many celebrities whose voice carries around the world and who are licensed hams (statemen, royalties, CEO of telecomm and Internet companies, TV producers, Gen. of US forces and scientists Nobel prices) that if ITU could have their support, the conclusions of their future report could change a lot... All these hams want that our bands be preserved but there are also involved in the use of the spectrum. They could arg in our side. See some names on : http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm (first half). But maybe that I dream alive Thierry ON4SKY, LX3SKY -- Walt Davidson Email: g3nyy @despammed.com |
"Walt Davidson" wrote in message ... On Sun, 19 Oct 2003 06:13:16 -0400, Bill wrote: But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. That didn't seem to stop the USA going its own way earlier this year, contrary to the wishes of the UN. Indeed and lobbying are often link to financial interests. Noone broadcaster (and still less with the future DRM, the digital AM) will never accept that its spectrum be reduced but the one of hams could be... There is maybe one way to fight against a potential reduction of our bands or increasing of the noise level. A good way to make the pressure on ITU in order that they protect our rights, IMHO, should be to request the help of some famous people. There are so many celebrities whose voice carries around the world and who are licensed hams (statemen, royalties, CEO of telecomm and Internet companies, TV producers, Gen. of US forces and scientists Nobel prices) that if ITU could have their support, the conclusions of their future report could change a lot... All these hams want that our bands be preserved but there are also involved in the use of the spectrum. They could arg in our side. See some names on : http://www.astrosurf.com/lombry/qsl-rfi-bpl.htm (first half). But maybe that I dream alive Thierry ON4SKY, LX3SKY -- Walt Davidson Email: g3nyy @despammed.com |
Walt Davidson wrote:
On Sun, 19 Oct 2003 06:13:16 -0400, Bill wrote: But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. That didn't seem to stop the USA going its own way earlier this year, contrary to the wishes of the UN. But... but... weapons of mass destruction... imminent threat... nuclear program... 9/11 connection... gassed his own people... at least Wolfovitz/Rumsfeld worked for their lobby - what's Blair's excuse? 73 ... WA7AA -- Anti-spam measu look me up on qrz.com if you need to reply directly |
Walt Davidson wrote:
On Sun, 19 Oct 2003 06:13:16 -0400, Bill wrote: But if we (the USA) are treaty bound to the ITU; this treaty is first in the heirarchy of laws in the USA (it is in the Constitution) ;-) Thomas Jefferson and other "founding fathers" were very serious when they warned the new nation to take making treaties very seriously. That didn't seem to stop the USA going its own way earlier this year, contrary to the wishes of the UN. But... but... weapons of mass destruction... imminent threat... nuclear program... 9/11 connection... gassed his own people... at least Wolfovitz/Rumsfeld worked for their lobby - what's Blair's excuse? 73 ... WA7AA -- Anti-spam measu look me up on qrz.com if you need to reply directly |
"Walt Davidson" wrote in message
... On Sun, 19 Oct 2003 17:07:08 GMT, Zoran Brlecic wrote: But... but... weapons of mass destruction... What weapons of mass destruction? imminent threat... What immininent threat? nuclear program... What nuclear program? 9/11 connection... What 9/11 connection? gassed his own people... Yes, probably. at least Wolfovitz/Rumsfeld worked for their lobby - what's Blair's excuse? He was taken for a ride by the US President and his cronies. He will not be such a soft touch next time. 73 de G3NYY Yeah? OK -- ;) 73 de Frank Turner-Smith G3VKI - mine's a pint. |
"Walt Davidson" wrote in message
... On Sun, 19 Oct 2003 17:07:08 GMT, Zoran Brlecic wrote: But... but... weapons of mass destruction... What weapons of mass destruction? imminent threat... What immininent threat? nuclear program... What nuclear program? 9/11 connection... What 9/11 connection? gassed his own people... Yes, probably. at least Wolfovitz/Rumsfeld worked for their lobby - what's Blair's excuse? He was taken for a ride by the US President and his cronies. He will not be such a soft touch next time. 73 de G3NYY Yeah? OK -- ;) 73 de Frank Turner-Smith G3VKI - mine's a pint. |
"AK" wrote in message news:mTkkb.810947$YN5.819762@sccrnsc01... "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ So here's a question: How many members of the US Congress and Senate are hams? What are their names, phone numbers, etc? |
"AK" wrote in message news:mTkkb.810947$YN5.819762@sccrnsc01... "Thierry" see my website wrote in message ... Hi, Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... The problem in the States is that the ITU does not pay PAC bribes to Congress for overlooking the obvious, and political hack FCC commissioners have no concept of the technology they are supposed to be regulating. But, what do expect out of a group of lawyers who were hired based on what they could do to bring home the bacon to Congress from rich special interest groups? But who knows, maybe a bunch of US hams buying 10 KW linear amplfiers will help the economy out and return Congress to a balanced budget for one more blue-moon occasion? Yeah, sure - that's it, BPL will save the U.S. economy. ak K4YKZ So here's a question: How many members of the US Congress and Senate are hams? What are their names, phone numbers, etc? |
What is the problem here? _REAL_ Radio Hams work with
signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! "Thierry" see my website wrote in message ... Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... |
What is the problem here? _REAL_ Radio Hams work with
signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! "Thierry" see my website wrote in message ... Do you remember the problem caused by broadcasting tests via the power line? A lot of radio amateur have to support the RFI causes by these tests everywhere in Europe. All hope is not lost. ITU officially recognized this was unacceptable... |
"Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. |
"Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. |
Even so, would not the modulation characteristic be known, and therefore
a noise blanker developable, very much the way that Radio Hams do things? Brenda Ann wrote in message ... "Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. |
Even so, would not the modulation characteristic be known, and therefore
a noise blanker developable, very much the way that Radio Hams do things? Brenda Ann wrote in message ... "Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. |
"Brenda Ann" wrote in message ...
The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. to which, "Airy R. Bean" replied, in his usual, unhelpful, childish, and predictably boring, repetitive manner... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, butnot for Radio Hams! ....which is really the NG equivalent of a noise source of 40dB over S9 QRM. Dave |
"Brenda Ann" wrote in message ...
The problem is that this particular noise source produces 40dB OVER S-9 QRM at 150 feet from the source... IIRC what I have read correctly.. to which, "Airy R. Bean" replied, in his usual, unhelpful, childish, and predictably boring, repetitive manner... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, butnot for Radio Hams! ....which is really the NG equivalent of a noise source of 40dB over S9 QRM. Dave |
Airy R. Bean wrote:
Even so, would not the modulation characteristic be known, and therefore a noise blanker developable, very much the way that Radio Hams do things? I'm not sure that it would possible Gareth to the extent needed. The problem is that local noise depends on the activity of local PLC modems, each of which is going to produce an additive but independent QRM. You wouldn't know beforehand when data was going to be requested or sent. It just sounds like random data bursts spread over a wide spectrum. Yes, some suppression might be possible by taking a wide bandwidth and somehow using cancellation. But getting 40dB or more of rejection I think would be very difficult. The galling thing about PLC/BPL is that the vested interests (i.e. the power companies) seem to think that they can ignore all other spectrum users. Yet the bandwidth they're offering will soon be insufficient to meet the broadband demands. At least with ADSL line bandwidth can be shared among a small number of subscribers. Greater bandwidth can be achieved by reducing that contention ratio. But I wonder how many houses are served by the same power substation on average. IMO, PLC/BPL is the wrong technology too late. Even ADSL is going to struggle to meet the bandwidth for on-demand video streaming. As a final irony, now that the ITU has dropped mandatory CW, CW with its much lower bandwidth offers the best chance in the presence of such wide spectrum noise. Looks like my pursuit of CW as a mode was worth it after all ;-) David, M0DHO |
Airy R. Bean wrote:
Even so, would not the modulation characteristic be known, and therefore a noise blanker developable, very much the way that Radio Hams do things? I'm not sure that it would possible Gareth to the extent needed. The problem is that local noise depends on the activity of local PLC modems, each of which is going to produce an additive but independent QRM. You wouldn't know beforehand when data was going to be requested or sent. It just sounds like random data bursts spread over a wide spectrum. Yes, some suppression might be possible by taking a wide bandwidth and somehow using cancellation. But getting 40dB or more of rejection I think would be very difficult. The galling thing about PLC/BPL is that the vested interests (i.e. the power companies) seem to think that they can ignore all other spectrum users. Yet the bandwidth they're offering will soon be insufficient to meet the broadband demands. At least with ADSL line bandwidth can be shared among a small number of subscribers. Greater bandwidth can be achieved by reducing that contention ratio. But I wonder how many houses are served by the same power substation on average. IMO, PLC/BPL is the wrong technology too late. Even ADSL is going to struggle to meet the bandwidth for on-demand video streaming. As a final irony, now that the ITU has dropped mandatory CW, CW with its much lower bandwidth offers the best chance in the presence of such wide spectrum noise. Looks like my pursuit of CW as a mode was worth it after all ;-) David, M0DHO |
"RVMJ" wrote in message
... As the result of a deliberate manoeuvre, the Galileo spacecraft collided with the planet Jupiter at an estimated time of 12:49:36 PDT on September 21st this year. Signal had been lost at 12:43:14 pm as Galileo passed behind Jupiter at a height of 5768 miles. Descent angle was 22 degrees and the impact speed 108,000 mph, a little more than the 106,500 mph of the Galileo probe, which entered Jupiter's atmosphere in December 1995. Galileo's transmitter had an output power of between 15 to 20 watts to an antenna having 7 db of gain. Received power at the Deep Space Net was -167 dBm. The DSN receivers track frequencies with extreme precision. The frequency gate for Galileo was normally about 0.3 Hz for a carrier frequency of 2295 MHz, but could be widened to 3 Hz for a moon flyby or planetary impact. Normally, Galileo put all the transmitter power into data sidebands plus or minus 360 kHz from the nominal carrier. This is called suppressed-carrier working, or a modulation index of 90 degrees. However, a pure-tone carrier would be less-difficult to track near impact, so 5.5 hr before impact the modulation index was shifted to 60 degrees. This has the effect of putting more power into the carrier at the expense of that in the data sidebands. Four hours before impact the data rate was changed from 20 bps to 32 bps in order to gather as much science. However, Galileo's engineers noticed that their real-time displays had stopped working. Wide-spectrum recorders had captured the raw signals, and the engineers are now using special decoders to find the data, which is 5 dB below the noise level. Obviously a bunch of Amateurs.....NOT. And all without Gareth's "Big K" ;-) -- 73 Brian G8OSN www.g8osn.org.uk www.amateurradiotraining.org.uk for FREE training material for the UK Foundation and Intermediate Licences www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio |
"RVMJ" wrote in message
... As the result of a deliberate manoeuvre, the Galileo spacecraft collided with the planet Jupiter at an estimated time of 12:49:36 PDT on September 21st this year. Signal had been lost at 12:43:14 pm as Galileo passed behind Jupiter at a height of 5768 miles. Descent angle was 22 degrees and the impact speed 108,000 mph, a little more than the 106,500 mph of the Galileo probe, which entered Jupiter's atmosphere in December 1995. Galileo's transmitter had an output power of between 15 to 20 watts to an antenna having 7 db of gain. Received power at the Deep Space Net was -167 dBm. The DSN receivers track frequencies with extreme precision. The frequency gate for Galileo was normally about 0.3 Hz for a carrier frequency of 2295 MHz, but could be widened to 3 Hz for a moon flyby or planetary impact. Normally, Galileo put all the transmitter power into data sidebands plus or minus 360 kHz from the nominal carrier. This is called suppressed-carrier working, or a modulation index of 90 degrees. However, a pure-tone carrier would be less-difficult to track near impact, so 5.5 hr before impact the modulation index was shifted to 60 degrees. This has the effect of putting more power into the carrier at the expense of that in the data sidebands. Four hours before impact the data rate was changed from 20 bps to 32 bps in order to gather as much science. However, Galileo's engineers noticed that their real-time displays had stopped working. Wide-spectrum recorders had captured the raw signals, and the engineers are now using special decoders to find the data, which is 5 dB below the noise level. Obviously a bunch of Amateurs.....NOT. And all without Gareth's "Big K" ;-) -- 73 Brian G8OSN www.g8osn.org.uk www.amateurradiotraining.org.uk for FREE training material for the UK Foundation and Intermediate Licences www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio |
"Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! Is that why CBers use echo boxes so they can sound like SSB voices, without the carrier insertion? ak |
"Airy R. Bean" wrote in message ... What is the problem here? _REAL_ Radio Hams work with signals that are deep in the noise all the time. There might be a concern here by CBers who want S9 BBC quality, but not for Radio Hams! Is that why CBers use echo boxes so they can sound like SSB voices, without the carrier insertion? ak |
"RVMJ" wrote in message ... Airy R. Bean wrote: "Thierry" wrote: ... Wide-spectrum recorders had captured the raw signals, and the engineers are now using special decoders to find the data, which is 5 dB below the noise level. Obviously a bunch of Amateurs.....NOT. Mmm? There is a software accessible to amateurs that can detect signal 10 dB below the noise : FFTDSP See my commentaries on http://www.astrosurf.com/lombry/soft-calc.htm#FFTDSP and a small review in French at the end of this page, http://www.astrosurf.com/lombry/sate...tificiels5.htm It is not much different from a SETI application. Thierry ON4SKY, LX3SKY -- from RVMJ (at) Bigfoot (dot) com |
"RVMJ" wrote in message ... Airy R. Bean wrote: "Thierry" wrote: ... Wide-spectrum recorders had captured the raw signals, and the engineers are now using special decoders to find the data, which is 5 dB below the noise level. Obviously a bunch of Amateurs.....NOT. Mmm? There is a software accessible to amateurs that can detect signal 10 dB below the noise : FFTDSP See my commentaries on http://www.astrosurf.com/lombry/soft-calc.htm#FFTDSP and a small review in French at the end of this page, http://www.astrosurf.com/lombry/sate...tificiels5.htm It is not much different from a SETI application. Thierry ON4SKY, LX3SKY -- from RVMJ (at) Bigfoot (dot) com |
"Airy R. Bean" wrote in message
... Taking the lead from the suppressors that were developed to deal with the supposedly random Russian "Woodpecker" is that necessarily the case? The "Woodpecker" wasn't "supposedly" random, it was pseudo random - not the same thing at all. In fact, successive pulses even had 'glitches' in the same position - an artefact of the way the short pulses were generated from a long (31 or 33- it was along tome back) bit sequence. As the whole idea was to give a predictable "compressed pulse" the thought that is could be "supposedly" random is not creditable. -- 73 Brian G8OSN www.g8osn.org.uk www.amateurradiotraining.org.uk for FREE training material for the UK Foundation and Intermediate Licences www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio |
"Airy R. Bean" wrote in message
... Taking the lead from the suppressors that were developed to deal with the supposedly random Russian "Woodpecker" is that necessarily the case? The "Woodpecker" wasn't "supposedly" random, it was pseudo random - not the same thing at all. In fact, successive pulses even had 'glitches' in the same position - an artefact of the way the short pulses were generated from a long (31 or 33- it was along tome back) bit sequence. As the whole idea was to give a predictable "compressed pulse" the thought that is could be "supposedly" random is not creditable. -- 73 Brian G8OSN www.g8osn.org.uk www.amateurradiotraining.org.uk for FREE training material for the UK Foundation and Intermediate Licences www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio |
On Mon, 20 Oct 2003 21:11:45 +0100, "Brian Reay"
wrote: www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio still waiting for the name of someone in the phoenix radio club that i can contact to learn more about morse code. |
On Mon, 20 Oct 2003 21:11:45 +0100, "Brian Reay"
wrote: www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio still waiting for the name of someone in the phoenix radio club that i can contact to learn more about morse code. |
"Zoran Brlecic" wrote in message ... snip [Gasp!]... but that could mean one thing only: president Wolf... I mean president G.W.Bush and his cronies lied to the American people!!! Hmm, politicians lying to their constituents to the point of having hundreds of lost lives in order to satisfy the lobby of a foreign country, while filling their pockets in the process? No ****ing way! There's gotta be a more rational explanation. This must be a vast liberal-anti-Christian-communist-leftist-atheist-terrorist-Clinton-UN-Franco-Ger man conspiracy. Yeah, that's what it is. Whew! Life makes sense again. 73 ... WA7AA You're an American aren't you ?? Steve Terry |
"Zoran Brlecic" wrote in message ... snip [Gasp!]... but that could mean one thing only: president Wolf... I mean president G.W.Bush and his cronies lied to the American people!!! Hmm, politicians lying to their constituents to the point of having hundreds of lost lives in order to satisfy the lobby of a foreign country, while filling their pockets in the process? No ****ing way! There's gotta be a more rational explanation. This must be a vast liberal-anti-Christian-communist-leftist-atheist-terrorist-Clinton-UN-Franco-Ger man conspiracy. Yeah, that's what it is. Whew! Life makes sense again. 73 ... WA7AA You're an American aren't you ?? Steve Terry |
"class_a_zpk_12wpm" .uk.net wrote in message ... On Mon, 20 Oct 2003 21:11:45 +0100, "Brian Reay" wrote: www.phoenixradioclub.org.uk - a RADIO club specifically for those wishing to learn more about amateur radio still waiting for the name of someone in the phoenix radio club that i can contact to learn more about morse code. The web site should have the name of a contact person. |
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