 
DataRiker
Premium
join:2002-05-19
Metairie, LA
clubs: | Catchy title i always wondered about that. | |
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TheMadSwede
Premium
join:2001-01-30
Holland, MI | Re: Catchy title Great. Thanks for your contribution. | |
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CPM
join:2001-08-24
Miami, FL
| Wi-fi Idea This is an old idea in the TV movie techWar »www.imdb.com/title/tt0111385/ they showed that the whole world was wireless and everything was hooked up to the internet.
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Broadwayman.com - Internet portal for Everything Broadway and New York. | |
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Voyager2K2
join:2001-10-04
Wayne, PA
edit:
September 13th, @11:39AM
| Philly's Nightmare Philadelphia's new digital emergency radio (police, fire, EMT) doesn't work because of cellular phone interference.
»cms.firehouse.com/content/articl···id=34950
Philly's system is 800Mhz.
So there HAMs. Put that in your pipe and smoke it.
Should we ban cell phones that create a REAL (not imagined) problems? Oh wait a minute. HAMs don't use 800Mhz so I guess cell phones are OK. | |
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Steve
ho ho ho dammit
Consultant
join:2001-03-10
Yorba Linda, CA
| Re: Philly's Nightmare What's this got to do with hams?]
If people are allocating two uses (public safety and cellphones) in the same band, then that sounds like a pretty bad idea, and it certainly ought to be fixed.
But the radio amateurs have no dog in this fight.
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Stephen J. Friedl * Security Consultant * Tustin, California USA * my web site | |
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richk_1957
If ..Then..Else
Premium
join:2001-04-11
Minas Tirith
| Re: Philly's Nightmare I checked & you're right
The radio amateurs have 420-450 Mhz and then 902-928Mhz, nothing around 800. So don't blame any interference on us.
I can't find any recent radio frequency allocation lists, but it's getting more & more crowded, so the spectre of interference crops up. | |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs:
| Re: Philly's Nightmare said by richk_1957  :
I can't find any recent radio frequency allocation lists, but it's getting more & more crowded, so the spectre of interference crops up.
»www.ntia.doc.gov/osmhome/allochrt.html
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I registered on DSLReports/BroadbandReports to talk about Broadband and DSL. Did you see GWReports or JKReports because I sure as hell didn't. Enough with the political bullshitting already.Free Kevin | |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs: | Re: Philly's Nightmare I've lost the ability to post URLs | |
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sabersaw
Premium
join:2001-08-21
Dayton, OH
| said by Voyager2K2 :
Philadelphia's new digital emergency (police, fire, EMT) doesn't work because of cellular phone interference.
»cms.firehouse.com/content/articl···id=34950
Philly's system is 800Mhz.
So there HAMs. Put that in your pipe and smoke it.
Should we ban cell phones that create a REAL (not imagined) problems? Oh wait a minute. HAMs don't use 800Mhz so I guess cell phones are OK.
yeah, once again this problem is money talking, without thinking about science and existing services. Nextel has pushed there way into frequencies that pollute public service. | |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs:
| Re: Philly's Nightmare When the FCC wanted to give Nextel some PCS spectrum, Verizon Wireless jumped in and cried foul and offered some cash for it.
This put them in a unique position. Either Verizon Wireless doesn't care about public safety or they are spectrum whores and still don't care about public safety.
Either way I thought it was kind of funny.;)
--
I registered on DSLReports/BroadbandReports to talk about Broadband and DSL. Did you see GWReports or JKReports because I sure as hell didn't. Enough with the political bullshitting already.Free Kevin | |
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sabersaw
Premium
join:2001-08-21
Dayton, OH
| Re: Philly's Nightmare yeah, I remember reading and responding to that topic on the news here. I can understand that Verizon doesn't care about public safety, that is not expected of them. What does surprise me is the FCC and their actions or lack of. I know little of cell phone modulation types, but my guess is your first response to the iDen signal being dirtier than tested is the true root of this disaster. | |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs: | The problem is Nextel. They don't use the same A/B frequencies as the rest of the cellular carriers. Nextel uses the same SMR band as trunking systems. iDEN just seems to bleed a lot. | |
| | ernie870654
join:2002-04-22
Cumming, GA
| Don't be silly!
The Nextel & Public Safety communications problem is related to adjacent channel interference. The article you referenced identified this as...I quote "cell-phone signals are bumping up against public-safety channels"
It was poor engineering analysis on the part of the FCC engineers that allowed this to happen.
BPL and Ham radio is a co-channel problem which even a junior RF engineer can understand.
....and yes, I am a Ham and I work in the wireless industry.
ernie870654 | |
| | | cghh
join:2001-01-15
Milpitas, CA
edit:
September 13th, @01:18PM
| Re: Philly's Nightmare I read the reference articles, and they first talk about cellular interference, and then continue on talking about Nextel, which is a different beast. AFAIK, the interference between wireless phones and public safety radios involves only Nextel, since they share the same frequency band (SMR) as the 800MHz public safety radios. The cellular bands do not overlap with the SMR band. | |
| | RayW
Premium
join:2001-09-01
Layton, UT
clubs:
 ·XMission
| quote:
As a result, a firefighter making a call at an 850-MHz frequency might unknowingly be standing under a cell-phone antenna transmitting at 851 MHz. One signal could block the other.
GOOD GRIEF! Assuming that the article had the facts straight, what idiot put an emergency band one MHz away from a cell phone frequency? That is as bad as the idiots who want BPL (at least in my experience with RF interference).
But all that aside, as of October 2003 the 849-851 MHz band was reserved for Aeronautical Mobile use, what is a land mobile public safety outfit doing there? 851-866 MHz is land mobile, which covers one set of cell phone frequencies, so they are where they belong (old analog phones?). Maybe they are splattering a bit considering the ineptitude of the phone company, but that is also a different story.
FYI GSM cell freqs are :
850 MHz (824.2 - 848.8 MHz Tx; 869.2 - 893.8 MHz Rx)
900 MHz (880-2 - 914.8 MHz Tx; 925.2 - 959.8 MHz Rx)
Which would explain why sometimes my weather station looses signal (around 915 MHz).
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I am not lost, I find myself every time. | |
| | | cghh
join:2001-01-15
Milpitas, CA
| Re: Philly's Nightmare said by RayW :
FYI GSM cell freqs are :
850 MHz (824.2 - 848.8 MHz Tx; 869.2 - 893.8 MHz Rx)
900 MHz (880-2 - 914.8 MHz Tx; 925.2 - 959.8 MHz Rx)
Which would explain why sometimes my weather station looses signal (around 915 MHz).
The 850MHz band you list is the US cellular A/B band, in which various protocols are used, such as AMPS (analog), IS-136 (U.S. "TDMA"), CDMA, and (only recently) GSM. The SMR band, where Nextel and the public safety radios operate, is 806-824MHz for the uplink (from the mobile), and 851-869MHz for the downlink (to the mobile). | |
| | | | RayW
Premium
join:2001-09-01
Layton, UT
clubs:
·XMission
| Re: Philly's Nightmare True cghh, but there is also the band from 851-866 MHz which I THINK is one of the old analog cell phone bands. I probably should not have included the 850 and 900 MHz GSM bands, but did so so someone who only looked at those would know I was not confused (more than I usually am that is).
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I am not lost, I find myself every time. | |
| | | | | | | | | | cghh
join:2001-01-15
Milpitas, CA
| said by RayW :
True cghh, but there is also the band from 851-866 MHz which I THINK is one of the old analog cell phone bands. I probably should not have included the 850 and 900 MHz GSM bands, but did so so someone who only looked at those would know I was not confused (more than I usually am that is).
The 851-866 band is the SMR (trunked radio, including Nextel) downlink band. AFAIK, the FCC does not specify the protocols to be used in the cellular and PCS bands (except that AMPS must currently be offered in the cellular band); that is, there is no such thing as a "GSM" band in the U.S. The 850MHz band mentioned is just the U.S. cellular band, in which GSM can be used, along with any other protocol (AMPS, CDMA, IS-136). The GSM Consortium specifies definitions for GSM channels, some of which fall in the 850MHz cellular band, which are meaningful only if GSM happens to be used in that band. In Europe and other places, of course, regulations require that only GSM can be used in certain bands, but that is not the case in the U.S. | |
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sabersaw
Premium
join:2001-08-21
Dayton, OH | Re: Philly's Nightmare 851-866 mhz also serves analog simplex/repeater public safety for many towns, they receive Nextel interference as well. | |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs: | The US doesn't use the 900MHz band for cellular. It's one of the unlicensed ISM bands and used mostly for cordless phones. | |
| | | | RayW
Premium
join:2001-09-01
Layton, UT
clubs: | Re: Philly's Nightmare True pcs, that was a cut and past for fullness.
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I am not lost, I find myself every time. | |
| | w2co
join:2003-07-16
Longmont, CO
| I don't know what your problem is man. Hams share the 2.4 Ghz band with all the lousey 802.11b/g routers anyway. And the 2.4Ghz band is a weak signal satellite band to boot. The 800 Mhz band is only 100 Mhz away from the nearest ham band, and is hardly used at all. You should get more educated on this stuff before you make statements like that. This has nothing to do with BPL which also is a real pandora's box and uses entirely different frequency ranges, but you fail to seperate the two. What the heck are you smoking man? | |
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Air WAV
join:2000-09-16
Saint Louis, MO | Not True... If a network is deployed properly,i.e., low power, sectorized and according to FCC EIRP limits, it can work and does. | |
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dadkins
Go For It
Premium,MVM
join:2003-09-26
Hercules, CA
 ·Comcast
| Uh huh... ""because Wi-Fi uses unlicensed spectrum, interference problems will be immense--especially in the 2.4-GHz band"
DUH! So do thousands of cordless phones, Satellites, Microwave ovens... but we aren't bitching about those, are we? 
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Nuke 'em all, let God sort 'em out. | |
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Steve
ho ho ho dammit
Consultant
join:2001-03-10
Yorba Linda, CA
| Re: Uh huh... said by dadkins :
DUH! So do thousands of cordless phones, Satellites, Microwave ovens... but we aren't bitching about those, are we?
Actually, yes.
Many people have problems with cordless-phone interference, but because it's more or less a stable environment, changing the channel (which some phones do automatically) often makes the problem go away until a neighbor gets a new phone.
Steve
--
Stephen J. Friedl * Security Consultant * Tustin, California USA * my web site | |
| B
Premium,MVM
join:2000-10-28
| Author No Dummy?
I was going to dismiss "Dave Molta" as uninformed or having an economic agenda, but he apparently works at a university, not for a competing wireless technology.
He may or may not be full of it, but from his older articles he IS familiar with 802.11's features, standards, and limitations, so he may have a point.
Honestly, I would somewhat prefer that large scale 802.11 deployments use a different band than private in-house networks or home users, but I guess this is what you get with unlicensed spectrum...
-- B
--
In a realm outside causality and function | |
| davebenham
join:2002-01-31
Round Lake, IL
| beware, interferference lurks ahead I live in a suburban neighborhood, and my ISP is wireless (802.11b). I had a heck of a time getting an acceptable signal.
I think it should be noted, that even though wifi hotspots are all the rage, the technology was never originally designed to be deployed over such large areas. It was originally meant to set up in office environments with devices being tens of meters apart, not hundreds or thousands of meters apart.
Imagine setting up a single 10000 port ethernet hub (not switch, mind you). What kind of performance do you expect? I'd sooner use a 56k modem and expect better results.
The future of broadband is in wires and fiber, not wireless. Wireless must stay a short range option, or it's all over. There's only so much bandwidth to go around.
We can always look into subspace (like in Star Trek), there's probably a fair amount of unused bandwidth there.  | |
| |
See 7 replies to this post | |
Told Ya
@chcgil.ameritech
| History repeating I've said it before and I'll say it again: Unlicensed "WiFi" use of any frequency is the CB Radio of the New Millennium™. This will keep escalating until you can't use any of it. Adding new frequencies only postpones the problem for a few months.
Until true "smart radios" are developed for the consumer market--ones which make their own correct interference-avoidance decisions--and the ability to hook up a 100 watt amplifier to your Linksys (et. al) WAP (etc.) is taken away, this is just going to get worse.
The SMR interference to emergency radio is curable if whomever deployed the emergency system was competent enough to work it out with Nextel. Sharing among licensed services works a lot better than sharing between unlicensed neighbors | |
| 
fire100_old
Premium
join:2002-08-09
Michigan
clubs:
| Ottawa Wireless figured it out »www.ottawawireless.net/
Has got it down, they have a deal with the city, and has Wi-Fi Antennas all over the city. They have them on light poles, utility poles, etc.
The whole city is covered, you can get roaming access for your laptop for $24.99 a month. | |
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An Interference Crisis
Well...
:D:D:D
