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Mobile phone in hard environment
Hi,
I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. RoS |
Rocco wrote:
Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Get you an external mobile cellular antenna. That already solves the problem of operating a cellphone inside a "shielded" vehicle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
How about that antenna they sell on late night TV that sticks to your
battery? They claim is works anywhere. "Cecil Moore" wrote in message ... Rocco wrote: Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Get you an external mobile cellular antenna. That already solves the problem of operating a cellphone inside a "shielded" vehicle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
How about that antenna they sell on late night TV that sticks to your
battery? They claim is works anywhere. "Cecil Moore" wrote in message ... Rocco wrote: Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Get you an external mobile cellular antenna. That already solves the problem of operating a cellphone inside a "shielded" vehicle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"w4jle" W4JLE(remove this to wrote in message ... How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. It works just as well in any environment. It dosen't work at all. |
w4jle wrote:
How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. Sorry, "anywhere" doesn't include inside a Faraday shield. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
I would contend that it works as well in a faraday shield as it does in the
elevator. "Cecil Moore" wrote in message ... w4jle wrote: How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. Sorry, "anywhere" doesn't include inside a Faraday shield. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
w4jle wrote:
I would contend that it works as well in a faraday shield as it does in the elevator. Hi, Hi, ain't English great? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Yep! The antenna does work anywhere! Any antenna works anywhere. An
antenna inside a Faraday cage works just fine, but, outside the Faraday cage you still can't hear anything. :-) w4jle wrote: How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. |
Scam
Steve N. "w4jle" W4JLE(remove this to wrote in message ... How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. "Cecil Moore" wrote in message ... Rocco wrote: Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Get you an external mobile cellular antenna. That already solves the problem of operating a cellphone inside a "shielded" vehicle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Still a scam
Steve N. "w4jle" W4JLE(remove this to wrote in message ... How about that antenna they sell on late night TV that sticks to your battery? They claim is works anywhere. "Cecil Moore" wrote in message ... Rocco wrote: Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Get you an external mobile cellular antenna. That already solves the problem of operating a cellphone inside a "shielded" vehicle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
A passive repeater? Basically an antenna both inside and outside the
room joined by a piece of coax.. Yes it works. I had it working with my 2m HT inside the home unit with a yagi sitting at the end of the hallway, coax connected to the 5/8 on the roof of the house. (Only used the yagi cause it was handy) Maybe 2-3 S points better at the time. (best guess) One of our guys at work has a similar setup for his mobile phone on 1800Mhz at his home QTH in a valley. Since we install mobile phone sites I guess he would know.. He goes from no signal to noise free, how ever many dB that is. Uses two mobile whips and about 10m of RG58 (yuk!) Of course you'll have some losses in the system. Try it! Just remember that coax losses on phone frequencies are kind of high so I suggest you put the external antenna into a strong signal and think about using lower loss cable. The trick is to experiment until you get a good enough signal to use! (Unlike others I assume you want more than one phone to work inside the room and that it needs to be portable) I wont make any comments about filling the shielded room with other signals! Repeaters are a little expensive but they do exist. We often do installs in shopping centres, underground railways and high rise buildings using such equipment. (Where you actually want a small coverage area) I am pretty sure you can get an active wide band repeater as well. Since the phone uses separate TX and RX freqs and you have a shielded room you could get away with an amplifier running in each direction. (We did that also for a UHF voice repeater on 400MHz with 5.5MHz separatation - in a tunnel) Need a good set of cavities though. The installs that we do are often extended using optical fibre at the RF frequency with antenna interfaces at the remote end. You are talking a few bucks here by the way. Go and have a look at Nokia's website if the passive one fails.. Cheers Bob VK2YQA Rocco wrote: Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. RoS |
"Roger Halstead" wrote in message ... On 14 Jan 2004 11:54:38 -0800, (Rocco) wrote: I'm basing my answer on the subject line word "hard" and the "shielded environment" statement below. Hi, I have to provide mobile phone signal in a shielded environment. Maybe the only way is by using an antenna that capture a sufficiently strong signal outside the shielded room, and conveying that signal ( If it is truly a shielded room...forget it. It was shielded for a reason and you used the term "hard" suggesting it was intended to be shielded. Causing that shielding to fail could be grounds for hunting for a new job. using a coax-cable ) inside it, at the end of the cable some sort of repeater that provide the diffusion. IF you could get a passive repeater to work you would be causing a loss of integrity to the shielded room. I've never gotten a passive repeater to relay a signal strong enough to be useful. Does anyone has some other suggestion? Or if the idea is correct, are those repeater in commerce? And about the receiving antenna? Thanks in advance. Unless, contrary to your phrasing the room is not shielded by intent you really need to forget the whole thing. I used to have a work area in a double walled shielded cage. When the door was closed we could take 5 watt HTs less than a foot apart... One outside and one inside. We could see and hear each other through the screen but the HTs could not. Anything that could have let a signal in would have negated the purpose of the room. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com RoS I regularly use passive and active "repeaters" to convey RF signals into a shielded enclosure. Sometimes, I'm testing a system that requires a GPS signal. I use an active GPS antenna on the roof of my building, a 75-foot run of semi-rigid coax, and then into a low-noise pre-amp. The output of the pre-amp goes to a coaxial feedthrough port, and, on the inside of the chamber, I mount a passive GPS antenna (as a radiator). The active GPS antenna has a very narrow bandwidth, so out-of-band signals are reasonably well rejected and not imported into the chamber. Other times, I may be testing a device with a VHF / UHF data link. I usually just put a simple rod antenna in the chamber, mounted directly to the coax feedthrough port. Outside the chamber, I run coax to a test set / simulator, or I connect another rod antenna. True, this introduces more RF garbage into the chamber, but, if it becomes a problem, I can just stick a band-pass filter into the coax line. Works every time for me. Ed wb6wsn |
All of the 'Screen Rooms' [120 db isolation into the GHz region] I've
installed, used or managed have an instrumentation panel with various styles of feedthrough connectors. If your 'hard environment' is in fact an intentional shielded enclosure [AKA Screen Room] I would use a 100% solid shielded coax into the instrumentation panel then connect to an external antenna. |
On Fri, 16 Jan 2004 20:36:37 +1100, Bob Bob
wrote: A passive repeater? Basically an antenna both inside and outside the room joined by a piece of coax.. Yes it works. I had it working with my 2m HT inside the home unit with a yagi sitting at the end of the hallway, coax connected to the 5/8 on the roof of the house. (Only used the yagi cause it was handy) Maybe 2-3 S points better at the time. (best guess) My shop is metal lined with the only openings being two small windows besides the doors which are metal. I have never been able to get a passive set up to work in there and an HT is only marginal out in the yard. I figured the big antenna on the roof with a short run of hard line would do the trick, but no joy. I ended up using cross band repeat on 440 to the rig in the house. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com snip |
Hi Roger
I guess its a relative signal strength issue. I have never gone to the trouble to work out the efficiency of a passive setup but whichever way you look at it it will never work as well as a cable connected direct from and external aerial to the radio. Might even have a look at it this week if I get a chance. How does that phrase go? YMMV! Cheers Bob VK2YQA My shop is metal lined with the only openings being two small windows besides the doors which are metal. I have never been able to get a passive set up to work in there and an HT is only marginal out in the yard. I figured the big antenna on the roof with a short run of hard line would do the trick, but no joy. I ended up using cross band repeat on 440 to the rig in the house. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com snip |
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