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FCC to Reorganize 800mhz Band?
nick0909 writes "Years in the making, the FCC is finally
close to deciding if they will allow Nextel to pay for the reorganization of the 800mhz bandplan. In return the FCC will give Nextel a new band in which to operate their phones, where they won't destroy public safety communications. Other cell companies are angry because they had to pay millions for their GHz frequencies, and argue Nextel is getting off cheap. On top of this, if the 800MHz band gets re-sliced, will the FCC continue to push TV broadcasters out of 700MHz, which was supposed to go all to public safety in the coming years?"
900 MHZ, as someone already posted.
But on a related note, I have some pro-audio wireless mic gear that uses 800MHz; I think it's fairly common in UHF pro gear. I'd really hate to have to replace this stuff because I can't get a clean signal for my band gigs, and I'm sure I'm far from alone here. (And that leads me to a digression - I wish more of this pro gear would use programmable oscillators/ frequency synthesizers so they wouldn't lock you into just one or two frequencies. Bleah...)
-- *My* journal is more interesting than *yours*...
When I think 800mhz I think VHF UHF my self. Some people prefer to call it VHF for some reason.
Cable Channels 126-141 805.25-895.25mhz according to my Kworld video card. I've never seen these used.
UHF channel 69 801.25mhz.. 70-83 I believe were the ones realocated to celular 806-890mhz.
http://www.inactivex.net/cellular/800MHz.html
I'm less familar with the 800mhz emergency frequencies.
900mhz I believe is what you're thinking of... I'm a cheep bastard and I own a pair of 900mhz cordless phones.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
One police officer recounted how he came upon a man who had been shot in the back and was laying there bleeding, when the officer tried to radio in for help he found that he had no radio reception, so he had to wander out into the middle of the street holding his radio up to the sky until he found a spot with reception.
AMW has a site here where you can sign an online petition, and a description of the problem here
Additionally here's a link to the Consensus Plan which is supported by emergency first responders to eliminate interference. Apparently there have been over a 1000 cases of interference nationwide in these states since the first case was reported 5 years ago.
Getting a license from the FCC is like buying a house. It's in your interest to know your neighbors and to make an effort to be a good neighbor. With that in mind, here's a few notes on what this whole fuss over interference is really about.
1. direct interference - someone transmits on someone else's frequency. This happens occassionally by accident and usually gets fixed quick. Nextel was once fined for doing this unintentionally a few years ago near New Orleans, LA.
2. co-channel interference - two entities each have a license to use the same frequency in geographically overlapping areas. The two parties are mutually responsible for making equipment and operating adjustments to eliminate interference.
3. equipment mis-configuration (including co-located equipment) - different companies often share the same tower sites and often the signal from one company's transmitter will "leak" into another causing mixed products and emissions outside licensed frequencies.
4. receiver desensitivity caused by proximity to low elevation, high power transmitter sites (ie. cell towers).
Nextel is causing problems for other 800Mhz licensees mostly as a result of items 3 and 4. Non-Nextel cell towers (like Verizon, Sprint, and AT&T) also cause #4 above but the problem is more severe when near a Nextel tower site because the transmissions are in the same band as the other non-Nextel users' equipment.
-rickNexTel is the innovator of the "Push to talk" cel phone (something Verizon (vodaphone) has copied in some parts of the US)
They use yet another tech (aside from AMPS/TDMA/GSM/CDMA) called iDen (integrated digital enhanced network I think) that motorola came up with.
Their first phones were, quite apropriatly, referred to as "Bricks" (the old Ericson 888 world is stylish in comparison) but nowadays they're much better style-wise. They were really popular in replacing licensed and unlicensed handheld radios in construction/warehouse biz, and then got picked up on by the ISP folks (which is how I got my experience with them) and others who need a quick communication method.
The push to talk is charged at a much lower rate than normal minutes, and works mostly nationwide (if you believe the adverts). Of course being PTT, there's not "ring" or "accept" phase, so the phone just starts yapping when someone pushes a button. You can do point to point or point to multipoint messages.
I haven't had a nextel in about 5 years so some of my observations might be outdated, but while the PTT worked well, they had a bad habit of dropping calls on cel hops.
Hope that helps. Motorola's iDen site is here
Please send all UCE to scally@devolution.com so I can f
Ewww ... yuck. Folks need to understand that the two main communications modes used by public safety: dispatch and tactical. For dispatch you can use a cellular network. Examples of tactical comms are SWAT/hostage type situations or on-scene fire control. For tactical communications what you really want is direct peer-to-peer. You don't want to depend on your signal travelling all the way to a tower a half-mile away - and back again - just to talk to someone 100 feet away. This is critical when trying to talk from inside a burning building.
Less bandwidth? Not necessarily, ACSSB (amplitude compandored single side-band) fits inside a 5 khz wide channel.
Is clearer? Nope - the digital systems all use some form of speech compression which sacrifices sound fidelity for narrower bandwidth.
Is secure? No ... digital does not equal encryption. It's easier to encrypt once it's digital but requires key management. It's not a given.
Also, for public safety ... encryption is of little value ... reliability and interoperability among different agencies are more important. For most agencies, encrypting voice comms for surveillance activity and encrypting data terminal access is more than sufficient.
-rick