microwaves instead of telephone lines

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brey1234

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I am posting this because in the Pa STARNET system most of the "cell" sites
(used where high profile tower sites can not "see") are using phone lines for
connections to the system.



The police department plans to select a vendor within 45 days for the new
system, which will transmit via microwaves instead of telephone lines, police
spokeswoman Laura McElroy said. The project will be paid for through federal,
state and local grants, including about $6 million of homeland security money
earmarked to improve interoperability among local public safety agencies, she
said.
"I don't know if it would be foolproof, but it would be much less likely for
something like this to happen," she said.
http://www2.tbo.com/content/2008/mar/05/sliced-verizon-cable-affected-tampa-police-radio-s/
 
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rcvmo

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Howdy,
After reading the link, I side with them. My phonelines between my console and leased tower have gone down more than I can count over the last 7 years, sometimes for months without recoruse then we got stuck with a $700 service charge for soemthing that wasn't our fault. We're still looking at VoIP, but even the internet has it's fault's. T1's, ISDN even have the same problem.
rcvmo
 

zz0468

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I hope they use real Part 101 licensed radios instead of the unlicensed Part 15 crap so many vendors are pushing these days. I've spent a good part of my career designing and building microwave links for public safety, with an emphasis toward reliability, where cost is a secondary objective. It's not impossible to build a system that has less than 30 seconds of outage per year, but the people who fund these things often just look at the bottom line.

If they cheap out on this, they won't be much better. If they tell the engineer that thay want it to just work, then get the hell out of his way, it stands a chance of being successful.
 

iamhere300

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They can use the 4.9 band in part 90, and come up with a pretty
effective system. Of course, if they really want part 101, I have
a bunch of buildings full of former MCI, AT&T, IXC, and Intermedia
microwave systems....
 

greenthumb

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Looking at the rules, permanent point-to-point is pretty much discouraged in 4.9 GHz. People are doing it, but it's not entirely in compliance.

But, by far, microwave is the choice for your backhaul over anything copper and leased.
 

zz0468

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The equipment for 4.9 GHz is generally not suitable for ultra-reliable backbone service. It's intended for hot spots, temporary deployments, public safety WAN applications where similar Part 15 radios don't provide the necessary security or excusivity, and so on.

No, for this application, they need real protected radios, real coordinated and licensed frequencies, and real engineering to do it right. Anything less will shortchange the people who need this thing to work.
 

CAPTLPOL1

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The rules for 4.9GHz do not allow for permanent microwave fixed point relays.
 

zz0468

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CAPTLPOL1 said:
The rules for 4.9GHz do not allow for permanent microwave fixed point relays.
That is untrue. The rules DO allow permanent point to point links on a scondary non-interference basis.
 
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