700 mhz

wbloss

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Dec 19, 2002
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Joplin MO
Let me provide a bit broader of an answer. It used to be that a PD was fine with one frequency. Bigger departments 2 or 3 maybe. All that has changed as each department has found the need for dozens of separate communication channels. Most have gone to a trunked system where 4,5 6 or 30+ frequencies are all "connected" in a system. This way hundreds or more "talkgroups" can use 5 to 30 frequencies, as not ALL are in use at the same time.
We had run out of enough frequencies on VHF, then 400MHz/UHF, then eventually 800MHz, so the 700MHz spectrum was taken from TV upper channels and turned into spectrum for use by Law Enforcement and others.
Brief but more info!
 

avdrummerboy

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Jun 26, 2011
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High Desert, CA
700MHz is just a new area of very limited radio spectrum but it was designed from the get go with narrowband (12.5kHz) and ultra narrowband (6.25kHz) in mind. It is used a lot in digital radio systems and trunked radio systems, which as was said above is a way to take a few radio frequencies and either dividing up the frequencies themselves or the time those frequencies are used allow multiple people to use the same frequency. 700MHz also has advantages in a propagation and use level. It's not quite as near microwave frequencies as 850-865 MHz are so there is a little less absorption and line of sight propagation that you get with the higher end. It's also still high enough in frequency that high gain antennas are still small and manageable.

Other than that 700MHz is just a range of frequencies like any other.
 

merlin

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Jul 3, 2003
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South East Idaho
Might be out of place here, the 700Mhz band plan has been explained. ALL of our state, county, and city emergency services supposedly migrated to 700 mhz- P25 phse 1 trunked.
Now get this, monitoring the entire public safety range of this band, plus some,
in 3 days there has not been one single spike, No CC, no nothing on this band.
Frequencies found in the database, nothing there
I do get fire dispatch and some unknown dispatch on the old channels called fallback. (VHF-UHF)
I have to wonder if this is just still a planning move or these services found a new band like 1400.
 

GTR8000

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Oct 4, 2007
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10,636
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BEE00
Might be out of place here, the 700Mhz band plan has been explained. ALL of our state, county, and city emergency services supposedly migrated to 700 mhz- P25 phse 1 trunked.
Now get this, monitoring the entire public safety range of this band, plus some,
in 3 days there has not been one single spike, No CC, no nothing on this band.
Frequencies found in the database, nothing there
I do get fire dispatch and some unknown dispatch on the old channels called fallback. (VHF-UHF)
I have to wonder if this is just still a planning move or these services found a new band like 1400.
If you're within range of one of the ICAWIN sites and you're not finding any control channels between 769-775 MHz, then something is wrong on your end. Check your receiving equipment. I don't know exactly where in "South East Idaho" you are, but according to the system map, there are plenty of sites in that portion of the state.

 
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