Ari Silversteinn wrote:
Do we have to blanket or only blanket each locale, that is, the broadcasting stations of each locale? Not only will we miss those no AM/FM listeners, we will miss those that don't have their radios on. An aggressive, road sign campaign is planned something like " Turn On Your Radio, It Could Save Your Life" type of thing near each incident site. On Mon, 03 Oct 2005 12:58:40 -0400, J. Teske wrote: While Florida may have laws to this effect, in fact they are unenforcable because of federal preemption for all radio matters. Still illegal, just the wrong enforcement entity. A state or locality cannot for example legislate on TVI matters (though many have tried.) When they try, the FCC will send a notice to the locals that they are in charge and will handle enforcement. Unfortunately the FCC is unwilling to get involved in the matter of private contracts such as antenna exclusions in housing developments. Is there a reason that the locals try to overwrite Fed law then? That said, be aware that when it comes to radio useage in the US, the FCC is actually NOT the ultimate authority. They are responsible only for those frequencies which a military controlled panel has ceded to the FCC for administrative purposes. I can't remember the name right off hand, but during my federal career, I had to work with them and we actually were able to override an FCC allocation because it interfered with a military application. While the FCC played ball with the DOD outfit I worked for, the ultimate beneficiary of that allocation (a TV station) sued and the matter wound up in Federal Court. The court reaffirmed the DOD's ultimate sovreignity in this matter. It ultimately got resolved by some allocation juggling when a combination of the Court, The FCC and the DOD gave the plaintiff some "religion." W3JT Excellent point, in my research I saw this handoff or spectrum management authority of the DoD and it makes sense. This is a serious, additional consideration and is all the more reason to get the DHS' blessings. Thanks. Actually the DOD does not have any authority over radio spectrum. There are two federal agencies that do. One is the FCC, which we all know and love, the other is NTIA, the National Telecomunications Information Agency. NITA controls all federal radio frequencies. Since the DOD is a Federal Agency their frequencies are controled by NTIA the same as the FBI, CIA Secret Service, Dept of Homeland Security and any other federal alphabet soup agency. Dave N a FCC and a NTIA user |
Wonder no longer, because broadcasing at IF frequencies has been for
year the standard in the US. In spite of some rather silly speculative posts, this mechanism has proved itself for more than 10-years here. In a confined space such as a tunnel, a transmitter of 10-watts more than sufficint to get the job done, and using nothing more sophisticated than a simple wire radiator running the length of the tunnel. In Boston, we also retransmit commercial radio broadcasts into our tunnels, but that requires equipment dedicated to each radio channel that we re-broadcast, and that becomes very costly after 10 stations or so, hence there is a limit. The real challenge is in maintaining emergency communications to the outside from within our tunnels. All are serviced by the traditional leaky coax that runs along the top of the tunnel, but considering that all of these emergency services operate on their own indepdendent frequency bands, so servicing them simulteously becomes somwhat problematic. particularly when hand-held, low power devices enter the big picture. Harry C. |
wrote in message
oups.com... Wonder no longer, because broadcasing at IF frequencies has been for year the standard in the US. In spite of some rather silly speculative posts, this mechanism has proved itself for more than 10-years here. In a confined space such as a tunnel, a transmitter of 10-watts more than sufficint to get the job done, and using nothing more sophisticated than a simple wire radiator running the length of the tunnel. In Boston, we also retransmit commercial radio broadcasts into our tunnels, but that requires equipment dedicated to each radio channel that we re-broadcast, and that becomes very costly after 10 stations or so, hence there is a limit. The real challenge is in maintaining emergency communications to the outside from within our tunnels. All are serviced by the traditional leaky coax that runs along the top of the tunnel, but considering that all of these emergency services operate on their own indepdendent frequency bands, so servicing them simulteously becomes somwhat problematic. particularly when hand-held, low power devices enter the big picture. Harry C. All agreed, but that is in a tunnel, which has the advantage of not having to overcome the still-received commercial stations. The OP wants to do this out in the open, anywhere, any time. He also wanted to do it while driving at high speed for some reason, but I think he's quietly shelved that part of the idea. Cheers. Ken |
Suggestion: Why don't you also broadcast such "emergency" information over
the entire spectrum of wireless network frequencies? That way, you could post the information into every Usenet group on the globe. Just like you have done with these postings. "Ari Silversteinn" wrote in message ... Crossposted to: rec.radio.amateur.antenna,rec.radio.amateur.misc,r ec,radio.amateur.equipment Novitiate he I am learning AM broadcast basics in particular the issues regarding the geo-targeted broadcasting of alert messages from moving vehicles. Would most appreciate any assistance. Due to Katrina/Rita, the company I work for has been given the opportunity to demonstrate a messaging system that would reach out approximately 1 mile +/- in transmission deliverance. This would be an "overbroadcast" (my term) in that it would override local AM radio broadcasting to reach into cars, trucks etc. In particular, we are working with a stationary site (a chemical spill for instance) and an emergency vehicle that would move back and forth at and through the site, at up to 70 mph, broadcasting an alert, voice and tone message. Reading about LPAM, this looks technically possible but one concern I have is antennae size. A fire truck, for instance, could have an antenna mounted on its front, and up to 4 feet over the top of its roof, so we might look at as much as 20 feet of length. I realize this places us over the 3 meter max so one of the ???? is whether LFAM is realistic. Am I way off base here, can any antennae, fractal or other, or any AM antennae technology, be utilized to design an antenna and propagate this type of signal? All comments appreciated. -- Drop the alphabet for email |
"Ari Silversteinn" wrote in message ... On Mon, 3 Oct 2005 12:01:14 -0400, Fred W4JLE wrote: In that case, simply modify the sign to "Tune to 560, it could save your life" and use a discrete frequency low power transmitter. I assume you mean to take up an unused local channel? Or to bargain for time on a used one? Both ideas make sense. -- Drop the alphabet for email On Mon, 3 Oct 2005 21:47:29 -0000, Dave wrote: if this is for real time notification you don't have time to bargain or to find an unused channel... and who would listen to you anyway if it was unused? how often do you turn the knob on your car radio?? Often actually and I agree about the unused channel, at first blush what about the emergency broadcast system? that would seem to be the 'proper' method of emergency notification, its already set up for all sorts of local, regional, and national notifications. The EBS is voluntary, this is not. -- Drop the alphabet for email |
On Mon, 3 Oct 2005 17:58:33 -0400, Fred W4JLE wrote:
There are a couple of frequiencies for unlicensed low power am stations. You can see them in use by real estate folks selling houses. There are no commercial stations on the frequency. Yes, and at Disney World, etc. This is a very doable idea and may well solve FCC/DoD issues. -- Drop the alphabet for email |
Excellent point, in my research I saw this handoff or spectrum management authority of the DoD and it makes sense. This is a serious, additional consideration and is all the more reason to get the DHS' blessings. Thanks. On Mon, 03 Oct 2005 17:55:13 -0500, David G. Nagel wrote: Actually the DOD does not have any authority over radio spectrum. There are two federal agencies that do. One is the FCC, which we all know and love, the other is NTIA, the National Telecomunications Information Agency. NITA controls all federal radio frequencies. Since the DOD is a Federal Agency their frequencies are controled by NTIA the same as the FBI, CIA Secret Service, Dept of Homeland Security and any other federal alphabet soup agency. Dave N a FCC and a NTIA user Know of the NTIA but I believe that what is the reality is that the mil gets first dibs on frequencies, then hands off the rest and in a state of national emerg, they can pretty much takeover the airwaves. -- Drop the alphabet for email |
On Tue, 4 Oct 2005 14:57:01 +1300, Ken Taylor wrote:
All agreed, but that is in a tunnel, which has the advantage of not having to overcome the still-received commercial stations. The OP wants to do this out in the open, anywhere, any time. He also wanted to do it while driving at high speed for some reason, but I think he's quietly shelved that part of the idea. Cheers. Ken MOF, it has reared its ugly hi speed head again. -- Drop the alphabet for email |
On Mon, 03 Oct 2005 14:31:36 -0700, Richard Clark wrote:
On Mon, 3 Oct 2005 16:33:52 -0400, Ari Silversteinn wrote: OK, so we supply the amplification. OK, this is just a re-run of previous speculations. You don't know the depth of your energy budget crisis, do you? Open coffers. -- Drop the alphabet for email |
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