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Tech237
Moderator
Username: Tech237
Post Number: 1580
Registered: 4-2004
| | Posted on Wednesday, May 23, 2012 - 3:03 pm: | 
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seems most hospitals (at least here in Oregon) run a device that blocks cell phones in and around ER. OK, I give the possibility (remote) that a cell may interfer with equipmemnt, but surely the "blocker" would have the same possibility?
I won't even go into possible legalities of blocking any RF communications.
I thought about this while sitting at a Boise hospital while a fam,ily member was in surgery.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Scooterman
Junior Member
Username: Scooterman
Post Number: 25
Registered: 3-2012
| | Posted on Thursday, May 24, 2012 - 12:46 am: |
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They block signals in some hotels as well. While staying at the Beltera Casino in Indiana my cell phone had no signal available. Walk half way across the parking lot and I had five bars. They want you to use their system so they can make more money off of you. Is it legal? I would not think so, but I don't think a complaint to the FCC would get any action. |
Press_man
Advanced Member
Username: Press_man
Post Number: 520
Registered: 5-2008
| | Posted on Thursday, May 24, 2012 - 2:27 pm: |
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While in the ER here on the 4th of the this month, all those who came to see me used thier cells with no problems. How long that will be allowed, whoooo knows, there are signs. Since this facility is part of the Duke University heart institute, it may not be long. One of the local guys was told he couldn't use his HT in his room that he was paying mega $$ for. He checked out and transported to Sebastian Medical, he gets there and the HT won't hit the repeater because of distance. Go figure!
Pressman/KC4ZWM
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Tech237
Moderator
Username: Tech237
Post Number: 1582
Registered: 4-2004
| | Posted on Friday, May 25, 2012 - 8:45 am: |
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A couple of years back, we ran a Santa on Radio in the Kids Ward, and before doing so we tested the equipment for RFI issues with 100W (no they werent connected to a real patient just a staff memember), with absolutely no problems at all. At one stage we had 50W of 2m with a mag mounted antenna stuck on one of the pieces of equipment - if that didn't cause RFI, I suspect not much would.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Press_man
Advanced Member
Username: Press_man
Post Number: 525
Registered: 5-2008
| | Posted on Saturday, May 26, 2012 - 2:04 pm: |
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Scooterman mentioned cell signal blocking at Hotels/Motels. We were at the inlaws timeshare in the Orlando area and couldn't get signal. I called our carrier and found out I needed to turn my phone off then back on, find a strong signal on the complex and reset it again. It worked, now everytime we go there I reset. Oh; before I forget, inside Islands of Adventure at Universal, the cell won't work, but will work next door at Universal itself, figure that one out.
Pressman/KC4ZWM
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Tech833
Moderator
Username: Tech833
Post Number: 2168
Registered: 8-2002
| | Posted on Sunday, May 27, 2012 - 2:04 pm: |
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You guys are reading WAY too much into this.
Your cell phone signal meter doesn't show the strength of the signal, it shows what it THINKS the signal level is, based on bit errors. It is not an S meter like your CB or ham radio.
When a cell phone has "5 bars" of signal, then I turn on the signal generator set to the same control channel freq. the cellphone is locked on to, and turn it up, the signal bars go DOWN, not up. I am injecting up to -3 dB/m of signal, but the cellphone still reads zero bars.
So, based on that knowledge, it is possible that interference to the cellphone's signal can and does make the bars go DOWN.
Armed with that information, you can see how in a noisy 850 MHz., 1.9 GHz., and 2.5 GHz. area, your cellphone will see no coverage, when in fact the cell signal is still there, but external noise factors cause it to not work.
If you take a spectrum analyzer like a sitemaster into a hospital, you'll be amazed at the QRM level even at those frequencies.
A friend of mine (yes, I have a friend or two) works in a hospital, and even though cellphones usually don't work in the building to make voice calls, text messaging still works OK, but somewhat delayed.
Cellphone towers are usually around 600 mW per frequency (that's 0.6 watts). When you consider that the same frequency is used by multiple users at the same time (TDMA, GSM) or spread across huge spectrum (CDMA), then there is even less power available for each phone user.
That's why most hospitals still use pagers for staff. They work!
Paging transmitters use several hundreds of watts into high gain antennas (for KW's of ERP) and are multicast (multiple transmitters to cover the same areas). And, pagers usually operate on frequencies that penetrate building materials better than 1.9 GHz.
Not to mention that pager devices themselves are receive-only (they do not transmit) so they are unable to interfere with sensitive medical equipment. That also means their battery life is measured in months, not hours. You don't need to constantly plug a pager in to charge it, unlike a cellphone. Plus, when a pager battery is getting low, you have a week or more of notice that it is time to change it.
Your radio 'Mythbuster' since 1998
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Press_man
Advanced Member
Username: Press_man
Post Number: 528
Registered: 5-2008
| | Posted on Tuesday, May 29, 2012 - 5:49 pm: |
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Sounds about right 833. The areas I was referring to are heavy on people, traffic, cell useage, industrial noise, radios of different bands in use, even the magnetic pickups on the rides in the parks. The hospital here has good signal but will likely very soon stop cell useage on campass or at least in the building. Most of the med staff carry radios so they can be reached quick.
Pressman/KC4ZWM
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Scooterman
Junior Member
Username: Scooterman
Post Number: 30
Registered: 3-2012
| | Posted on Wednesday, May 30, 2012 - 9:34 am: |
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I carry my cell phone in the "OFF" condition. So when I was at Belterra on the fourth floor of the hotel and turned on my cell phone, it should have worked right? I called my carrier when I got home and asked "Why won't my cell phone work" in this location. Their answer was, "If you read the FCC statement....." More or less it says you may not cause disruption in other devices, but it is okay for your signal to get messed with. At least that's the understanding I have. I would not put a lot of weight in my understanding of it though. I have had way too many hard knocks to the head and when I read Government regulation speak it all turns into "Blah, blah, blah, drivel, snort." And I use to be a "D.M.I.R." with FAA authority so the language is not foreign to me, I lack the ability to comprehend it any more. |
Tech237
Moderator
Username: Tech237
Post Number: 1584
Registered: 4-2004
| | Posted on Wednesday, May 30, 2012 - 9:10 am: |
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833 - the hospital I was at, does not "jam " the cell per se, but actually shuts it down to the point it takes several minutes for the phone to worjk again after leaving the hospital.
But, and I repeat it, not matter if they jam or shut the cell down, surely the device used has as much chance of causing issues with equipment as the cell does in the first place.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Ducksoupe
New member
Username: Ducksoupe
Post Number: 7
Registered: 3-2012
| | Posted on Wednesday, May 30, 2012 - 6:51 pm: |
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some theaters do this and I am glad they do
Eddie
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Tech237
Moderator
Username: Tech237
Post Number: 1585
Registered: 4-2004
| | Posted on Thursday, May 31, 2012 - 8:29 am: |
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Ducksoupe - they do, and apart from the FCC angle, they could be in for a hefty lawsuit, if a person dies because an Emegecny services person doesn receive the phone call that should have had him responding to the emergency.
Don't laugh or say it cannot happen - it did in Australia around 1993.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Wizard200056
New member
Username: Wizard200056
Post Number: 2
Registered: 4-2011
| | Posted on Friday, July 06, 2012 - 10:19 pm: |
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One of the main reasons Hospitals and other facilities block cell phone use is to keep the staff from wasting company time with personal calls.I have first hand knowledge of a local hospital that installed a blocker after repeated failed attempts to limit personal cell phone use.It had nothing to do with interference of any kind.
Many Thanks to All Contribitors For Sharing Their Knowledge.
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Kc8gpd
Member
Username: Kc8gpd
Post Number: 53
Registered: 2-2004
| | Posted on Saturday, July 07, 2012 - 1:26 am: |
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hospitals, jails, VA's have access to a "cellular trap". it allows their registered phones full system access while denying (the actual walls of hospital act as a nice faraday shield) or only allowing outside devices 911 access.
basically it's an internal cell site that is programmed to not allow access to non employee cell phones. it's not a traditional wide band jammer.
Rev. Robert P. Chrysafis
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Tech237
Moderator
Username: Tech237
Post Number: 1593
Registered: 4-2004
| | Posted on Sunday, July 08, 2012 - 10:35 am: |
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KC8qpd - maybe, but it still comes under "interfering with a duly authorized federal approved radio service, and no matter how you want to cut it THAT is illegal.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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