DataRiker
Premium
join:2002-05-19
Metairie, LA
clubs: | Catchy title
i always wondered about that. |
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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
 ·Verizon FIOS
1 edit | 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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n2jtx
join:2001-01-13
Glen Head, NY
 ·Optimum Online
|  Well...
If I were to take a lesson from the BPL proponents I would say, I don't care about the interference and the problems it causes, I want my high speed Internet connection now! 
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I support the right to keep and arm bears. |
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Steve
I'm a PC, so shut up
Consultant
join:2001-03-10
Yorba Linda, CA
| reply to Voyager2K2
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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Air WAV
join:2000-09-16
Saint Louis, MO | reply to n2jtx
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
Can you do Blu?
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
I'm a PC, so shut up
Consultant
join:2001-03-10
Yorba Linda, CA
| 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
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Stephen J. Friedl * Security Consultant * Tustin, California USA * my web site |
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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
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In a realm outside causality and function |
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sabersaw
Premium
join:2001-08-21
Dayton, OH
| reply to Voyager2K2
Re: Philly's Nightmare
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: | reply to Voyager2K2
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. |
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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.  |
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ernie870654
join:2002-04-22
Cumming, GA
| reply to Voyager2K2
Re: Philly's Nightmare
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 |
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pcscdma
Chocobo Chocobo Random Battle
Premium
join:2004-01-14
Winterset, IA
clubs:
| reply to sabersaw
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.;)
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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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sabersaw
Premium
join:2001-08-21
Dayton, OH
| 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: | reply to davebenham
Re: beware, interferference lurks ahead
The 5GHz band is becoming popular for WISPs. One of the WISPs in my town seems to be converting. |
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cghh
join:2001-01-15
Milpitas, CA
2 edits | reply to ernie870654
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. |
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RayW
Premium
join:2001-09-01
Layton, UT
clubs:
 ·XMission
| reply to Voyager2K2
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. |
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cghh
join:2001-01-15
Milpitas, CA
| 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). |
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moonpuppy
join:2000-08-21
Glen Burnie, MD
·Verizon Online DSL
| reply to n2jtx
Re: Well...
said by n2jtx :
If I were to take a lesson from the BPL proponents I would say, I don't care about the interference and the problems it causes, I want my high speed Internet connection now!
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA  :D:D:D
You owe me a new keyboard. |
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