"Keep in mind that those wireless sound systems operate under the broadcast rules and as such they can only be used by broadcasters. They must enter the location of these devices into the database so the new white-space devices can know where they are. The rules also set aside two channels (12 MHz) where the new broadband devices can't operate.
The wireless sound and video devices are legitimately used by broadcasters for remote work at unspecified locations.
These tv-channel wireless sound devices are also illegitimately used by many people that are not broadcasters. That illegal use will not be protected by the database provisions"
I was told that what killed Iridium was the local Telecom laws.
Originally Iridium was going to bounce international calls directly satellite to satellite, but the local Telecoms screamed blue-murder so Iridium was forced to put ground-stations in each country and use conventional international links. So the cost of calls went way up.
It gets worse, it also means using multiple synchronous satellite links, so it has long time delays.
I don't really know, but it does sounds convincing.
2.4GHz is a "junk band" i.e your equipment is unlicensed. The disadvantage of being an unlicensed user is that you must accept any interference encountered.
If you do find the source, what are you going to do about it?
There are various LICENSED services in this band which are entitled to be there. Hams for instance are allowed 1500 Watt PEP on 2.4GHz.
I realise that I'm wasting my breath, but it is appalling how ignorant most SlashDot posters are when it comes to basic science.
For what it's worth:
Electromagnetic radiation (from cell phones, RFID, etc) is non-ionising. EM Interference (EMI) is well understood and manufactures go to enormous lengths to design out (and test for) EMI, especially with critical automotive systems.
Cosmic rays are in the completely different category of Ionizing radiation. This is also well understood, and is carefully considered in the design of critical systems (especially space craft, planes and military).
If Cosmic rays could seriously affect the relatively simple electronics in cars, then your (much more complex) desktop computer would be completely unusable.
Back in '77 when I started out with computers, I learnt to program the wonderful Casio accounting computer. It was built into an office desk and used a continuously circulating paper tape as the program storage. I can't remember the actual name of the O/S, but after all these years would love to read more about it....
It is appalling to see the dishonest arguments used by the proponents of BPL.
Sure Hams would be affected, but what about the hundreds of other essential services which cram into the H.F. bands?
Everything from Military, to Ambulance, Fire, Police, Aircraft, Marine, etc. rely on H.F. for reliable remote communications.
Ham Radio is an easy target ("just a bunch of nerds, who needs them?"), but whenever the spin is limited to Ham Radio, you know you are listening to a bunch of lying scumbags.
As a professional Communications Engineer, I can tell you that we must kill BPL!
Line Loss: The power lines are designed to carry 50/60 Hz power. They are woefully inefficient at higher frequencies (BPL frequencies are up to 1,000,000 times higher). The high Loss as H.F. means that data repeaters are needed every few poles.
Radio Interference: The H.F. bands are chock full of licensed users, many of them Emergency Services. Because the power lines are so unsuited to carrying H.F. signals, the result would be catastrophic interference both to and from these legitimate services. Note that Emergency Services use H.F. because they have no alternative to reliable long-distance communications.
High Noise Level: The Power lines are horrendously noisy. This high noise level (again) requires repeaters every few poles.
Poor Bandwidth: To prevent interference between repeaters, alternate line sections must use different frequency bands. Because the H.F. band is less than 30 MHZ wide (especially when you avoid aircraft frequencies, etc). The available bandwidth is hopelessly insufficient to provide a community with a broadband Internet service.
Latency: Because so many repeaters would be needed, the total latency makes the circuit unusable for services such as VOIP, etc.
Cost: BPL requires a very large amount of very expensive line plant. It must be capable of withstanding direct lightening strikes and can only be serviced by trained Line Staff. To work on the gear, the line usually has to be be shut down. Because of the high costs, BPL is particularly unsuited to servicing rural areas.
Slashdot Mirror
As has been posted elsewhare...
"Keep in mind that those wireless sound systems operate under the broadcast rules and as such they can only be used by broadcasters. They must enter the location of these devices into the database so the new white-space devices can know where they are. The rules also set aside two channels (12 MHz) where the new broadband devices can't operate.
The wireless sound and video devices are legitimately used by broadcasters for remote work at unspecified locations.
These tv-channel wireless sound devices are also illegitimately used by many people that are not broadcasters. That illegal use will not be protected by the database provisions"
I was told that what killed Iridium was the local Telecom laws.
Originally Iridium was going to bounce international calls directly satellite to satellite, but the local Telecoms screamed blue-murder so Iridium was forced to put ground-stations in each country and use conventional international links. So the cost of calls went way up.
It gets worse, it also means using multiple synchronous satellite links, so it has long time delays.
I don't really know, but it does sounds convincing.
But then sound waves attenuate much more rapidly that radio waves.
See above article on the voice powered Ham radio covering thousands of miles. .......
2.4GHz is a "junk band" i.e your equipment is unlicensed. The disadvantage of being an unlicensed user is that you must accept any interference encountered.
If you do find the source, what are you going to do about it?
There are various LICENSED services in this band which are entitled to be there. Hams for instance are allowed 1500 Watt PEP on 2.4GHz.
see http://en.wikipedia.org/wiki/High-speed_multimedia_radio
I realise that I'm wasting my breath, but it is appalling how ignorant most SlashDot posters are when it comes to basic science.
For what it's worth:
Electromagnetic radiation (from cell phones, RFID, etc) is non-ionising. EM Interference (EMI) is well understood and manufactures go to enormous lengths to design out (and test for) EMI, especially with critical automotive systems.
Cosmic rays are in the completely different category of Ionizing radiation. This is also well understood, and is carefully considered in the design of critical systems (especially space craft, planes and military).
If Cosmic rays could seriously affect the relatively simple electronics in cars, then your (much more complex) desktop computer would be completely unusable.
It's sad that only commercial modems are mentioned.
I well remember building a series of homemade modems starting in the early '80s.
There were many magazine articles for homebrew modems. Most of these derived from the FSK radio modems in widespread use by Hams at the time.
I found one...
http://museum.ipsj.or.jp/en/computer/office/0007.html
it used a box of relays as the processor. ....
State of the art
Back in '77 when I started out with computers, I learnt to program the wonderful Casio accounting computer. It was built into an office desk and used a continuously circulating paper tape as the program storage. I can't remember the actual name of the O/S, but after all these years would love to read more about it....
It is appalling to see the dishonest arguments used by the proponents of BPL.
Sure Hams would be affected, but what about the hundreds of other essential services which cram into the H.F. bands?
Everything from Military, to Ambulance, Fire, Police, Aircraft, Marine, etc. rely on H.F. for reliable remote communications.
Ham Radio is an easy target ("just a bunch of nerds, who needs them?"), but whenever the spin is limited to Ham Radio, you know you are listening to a bunch of lying scumbags.
As a professional Communications Engineer, I can tell you that we must kill BPL!
Here's what I did in that situation:
I put up a large white-board, and each time someone requested a job, I wrote it on a strip and put it at the bottom of the list.
When they complained about the delay, I pointed to the white-board and suggested that they negotiate with those above them for priority.
It worked well.........
'Radio spectrum is a natural resource, something that here in the US is owned by all of us American citizens,'
So we should hand it over to Big Business to make a profit from.
Great idea...
It's like Big Business saying "National Parks are not in use, so you should sign them all over to us..."
BPL can never work because:
Line Loss: The power lines are designed to carry 50/60 Hz power. They are woefully inefficient at higher frequencies (BPL
frequencies are up to 1,000,000 times higher). The high Loss as H.F. means that data repeaters are needed every few poles.
Radio Interference: The H.F. bands are chock full of licensed users, many of them Emergency Services. Because the power
lines are so unsuited to carrying H.F. signals, the result would be catastrophic interference both to and from these
legitimate services. Note that Emergency Services use H.F. because they have no alternative to reliable long-distance
communications.
High Noise Level: The Power lines are horrendously noisy. This high noise level (again) requires repeaters every few poles.
Poor Bandwidth: To prevent interference between repeaters, alternate line sections must use different frequency bands.
Because the H.F. band is less than 30 MHZ wide (especially when you avoid aircraft frequencies, etc). The available
bandwidth is hopelessly insufficient to provide a community with a broadband Internet service.
Latency: Because so many repeaters would be needed, the total latency makes the circuit unusable for services such as VOIP,
etc.
Cost: BPL requires a very large amount of very expensive line plant. It must be capable of withstanding direct lightening
strikes and can only be serviced by trained Line Staff. To work on the gear, the line usually has to be be shut down.
Because of the high costs, BPL is particularly unsuited to servicing rural areas.