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mobile (cell) phone jamming
"Nomen Nescio" wrote in message ... According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? what's the point in buying one, if you [legally] can't use it? |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 15:50:05 +0100 (CET), Nomen Nescio
wrote: According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. The article is four years old, £18.00 was mentioned and the product never appeared - at least not in the UK - where its use would be illegal. -- Hiram Hackenbacker |
mobile (cell) phone jamming
"Nomen Nescio" wrote in message ... According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. Why so you can haunt or Stalk alan erskine even more? |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 14:55:55 -0000, "NorwichLad"
wrote: According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? what's the point in buying one, if you [legally] can't use it? I am not sure that would stop me getting one and using in on my daily commute to Waterloo (in the non-mobiles car). -- Hiram Hackenbacker |
mobile (cell) phone jamming
-- For email please use: http://www.davetopping.com/usenet. "Jaime" wrote in message ... See http://www.globalgadgetuk.com/cell%2...%20jammers.htm |
mobile (cell) phone jamming
"Hiram Hackenbacker" wrote in message ... On Fri, 19 Dec 2003 14:55:55 -0000, "NorwichLad" wrote: According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? what's the point in buying one, if you [legally] can't use it? I am not sure that would stop me getting one and using in on my daily commute to Waterloo (in the non-mobiles car). Non Mobiles car? Didnt know swt had any of them. Jaime |
mobile (cell) phone jamming
"Nomen Nescio" wrote in message
... According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? I believe that jamming mobile phone frequencies can result in a prison sentence. Mike. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.552 / Virus Database: 344 - Release Date: 15-Dec-2003 |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 15:50:05 +0100 (CET), Nomen Nescio
wrote: According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? It is illegal in the U.S. http://wireless.fcc.gov/services/cel...ngjamming.html -- Hal Amateur Radio Station K1HK |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 17:57:28 +0100 (CET), Tarapia Tapioco
wrote: I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. It would be better if it had some directionality but not too much. I don't want to aim it at someone but it would be nice to be able to disconnect the loud phone user in front of me without affecting the text messager behind me. Can anyone point me in the right direction for designing this? http://gbppr.dyndns.org/PROJ/mil/celljam/ The site gets really slow at times. Suggest you save the schematics so you won't have problems if the site goes down. -----= 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! =----- |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 17:52:17 GMT, Hal wrote:
On Fri, 19 Dec 2003 15:50:05 +0100 (CET), Nomen Nescio wrote: According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? It is illegal in the U.S. http://wireless.fcc.gov/services/cel...ngjamming.html So is corporate price fixing, political bribes, and speeding; YOUR POINT BEING? -----= 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! =----- |
mobile (cell) phone jamming
Tarapia Tapioco wrote:
I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. What's the problem? If someone annoys me too much with a phone, I just offer to jam it somewhere. Manually. ;-) -- Paul Hovnanian note to spammers: a Washington State resident ------------------------------------------------------------------ On a clear disk, you can seek forever. |
mobile (cell) phone jamming
default wrote:
On Fri, 19 Dec 2003 17:57:28 +0100 (CET), Tarapia Tapioco wrote: I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. It would be better if it had some directionality but not too much. I don't want to aim it at someone but it would be nice to be able to disconnect the loud phone user in front of me without affecting the text messager behind me. Can anyone point me in the right direction for designing this? http://gbppr.dyndns.org/PROJ/mil/celljam/ Whenever I try to hit that site i get: Forbidden You don't have permission to access /PROJ/mil/celljam on this server. What's the story? -- Peter E. Lowrie ---------------------------------------------------------- |
mobile (cell) phone jamming
futureworlds wrote:
Even if they complained, would the police or even the UK equivalent of the FCC be interested in expending the resources to track down and prosecute a nut with a few mW transmitter? Oh, yeah. Big time. Operating a low-power illegal "normal" transmitter (like an unlicensed CB set) is one thing - a minor offence under Part I (s.1) of the Wireless Telegraphy Act; they'll just get the kit seized, and a Police caution. Perhaps a small fine if it's worth a prosecution. Maybe even a suspended jail sentence if it was shown to be interfering with licensed equipment (by accident). Deliberate jamming, on the other hand, is a Part II (s.13) offence, and a whole different order of magnitude. The Radiocommunications Agency (www.radio.gov.uk) will rain Hellfire on offenders: expect a jail term and/or (probably 'and') a stiff fine. And seizure of anything, not just txing equipment, that could be argued to be relevant to the offence. Jon -- SPAM BLOCK IN USE! Replace 'deadspam' with 'green-lines' to reply in email. Want a free solution to email spam? Try http://www.deadspam.com/ (Declaration of interest: I own/run the domain.) |
mobile (cell) phone jamming
there was talk that bush was planning to be party to some mobile phone
jamming action during his visit to blighty. how would that stand? oo. "Mike GW8IJT" wrote in message ... "Nomen Nescio" wrote in message ... According to an article in the Register, Anil Vora has invented a handheld phone jammer for about £30. http://www.theregister.co.uk/content/archive/7284.html But I can't find his company. Anyone know how to buy one of these? I believe that jamming mobile phone frequencies can result in a prison sentence. Mike. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.552 / Virus Database: 344 - Release Date: 15-Dec-2003 |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 21:28:16 -0000, "oo" wrote:
there was talk that bush was planning to be party to some mobile phone jamming action during his visit to blighty. No, he wanted the networks switched off. -- Iain the out-of-date hairydog guide to mobile phones http://www.hairydog.co.uk/cell1.html Browse now while stocks last! |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote:
Tarapia Tapioco wrote: I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. What's the problem? If someone annoys me too much with a phone, I just offer to jam it somewhere. Manually. ;-) When someone annoys me by yakking on a cell phone in a restaurant, meeting etc., I just join right in the conversation "Sure thing Bill. Friday's great. Just don't bring that whiny annoying wife of yours..." etc. I get some priceless looks. Bob |
mobile (cell) phone jamming
isnt that interfering with licenced bandwith?
oo wrote in message ... On Fri, 19 Dec 2003 21:28:16 -0000, "oo" wrote: there was talk that bush was planning to be party to some mobile phone jamming action during his visit to blighty. No, he wanted the networks switched off. -- Iain the out-of-date hairydog guide to mobile phones http://www.hairydog.co.uk/cell1.html Browse now while stocks last! |
mobile (cell) phone jamming
"oo" wrote:
wrote in message ... On Fri, 19 Dec 2003 21:28:16 -0000, "oo" wrote: there was talk that bush was planning to be party to some mobile phone jamming action during his visit to blighty. No, he wanted the networks switched off. isnt that interfering with licenced bandwith? Sorry, I think I must have woken up. For the past decade or three, I've been living in a dreamworld where the US ignores any international or national laws it considers inconvenient. Jon -- SPAM BLOCK IN USE! Replace 'deadspam' with 'green-lines' to reply in email. Want a free solution to email spam? Try http://www.deadspam.com/ (Declaration of interest: I own/run the domain.) |
mobile (cell) phone jamming
"Jon S Green" wrote:
futureworlds wrote: Even if they complained, would the police or even the UK equivalent of the FCC be interested in expending the resources to track down and prosecute a nut with a few mW transmitter? Oh, yeah. Big time. Operating a low-power illegal "normal" transmitter (like an unlicensed CB set) is one thing - a minor offence under Part I (s.1) of the Wireless Telegraphy Act; they'll just get the kit seized, and a Police caution. Perhaps a small fine if it's worth a prosecution. Maybe even a suspended jail sentence if it was shown to be interfering with licensed equipment (by accident). Speaking from personal experience many years ago this just didn't happen. Yes the DTI did go round in their detector vans when the problem got out of hand. Found out the people using, say, 500W 27MHz amps and hi-gain antennas with SSB rigs. Then normally told them to stop using it & get rid of it. Took gear off them if it was causing interference to phones/TVs/radio. I've never heard anyone get a fine. Never heard police involved. Police didn't want to know if people reported severe interference to them. Suspended jail sentence? Never heard of any. Deliberate jamming, on the other hand, is a Part II (s.13) offence, and a whole different order of magnitude. The Radiocommunications Agency (www.radio.gov.uk) will rain Hellfire on offenders: expect a jail term and/or (probably 'and') a stiff fine. And seizure of anything, not just txing equipment, that could be argued to be relevant to the offence. Have you ever seen this happen? Seisure I can see, but nothing else. The RA/DTI are/were a bunch of lazy sods :-) frag |
mobile (cell) phone jamming
Hello,
The RIS tend to go out at nights and weekends and can take months finding a station. It depends on the amount of overtime. "Richard Wood" wrote in message ... "Jon S Green" wrote: futureworlds wrote: Even if they complained, would the police or even the UK equivalent of the FCC be interested in expending the resources to track down and prosecute a nut with a few mW transmitter? Oh, yeah. Big time. Operating a low-power illegal "normal" transmitter (like an unlicensed CB set) is one thing - a minor offence under Part I (s.1) of the Wireless Telegraphy Act; they'll just get the kit seized, and a Police caution. Perhaps a small fine if it's worth a prosecution. Maybe even a suspended jail sentence if it was shown to be interfering with licensed equipment (by accident). Speaking from personal experience many years ago this just didn't happen. Yes the DTI did go round in their detector vans when the problem got out of hand. Found out the people using, say, 500W 27MHz amps and hi-gain antennas with SSB rigs. Then normally told them to stop using it & get rid of it. Took gear off them if it was causing interference to phones/TVs/radio. I've never heard anyone get a fine. Never heard police involved. Police didn't want to know if people reported severe interference to them. Suspended jail sentence? Never heard of any. Deliberate jamming, on the other hand, is a Part II (s.13) offence, and a whole different order of magnitude. The Radiocommunications Agency (www.radio.gov.uk) will rain Hellfire on offenders: expect a jail term and/or (probably 'and') a stiff fine. And seizure of anything, not just txing equipment, that could be argued to be relevant to the offence. Have you ever seen this happen? Seisure I can see, but nothing else. The RA/DTI are/were a bunch of lazy sods :-) frag |
mobile (cell) phone jamming
On Fri, 19 Dec 2003 21:44:04 GMT, Bob Stephens
wrote: On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote: Tarapia Tapioco wrote: I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. What's the problem? If someone annoys me too much with a phone, I just offer to jam it somewhere. Manually. ;-) When someone annoys me by yakking on a cell phone in a restaurant, meeting etc., I just join right in the conversation "Sure thing Bill. Friday's great. Just don't bring that whiny annoying wife of yours..." etc. I get some priceless looks. Bob Hey that's pretty good - worth a try. Now, what is your technique for getting the woman on the road in the SUV who is ambivalent about which lane she intends to use? -----= 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! =----- |
mobile (cell) phone jamming
snip
Can anyone point me in the right direction for designing this? http://gbppr.dyndns.org/PROJ/mil/celljam/ Whenever I try to hit that site i get: Forbidden You don't have permission to access /PROJ/mil/celljam on this server. What's the story? I know the site is slow - sometimes there's just a blip every few seconds on the download meter - othertimes it works normally. Can you hear me now? No. Good. Devices to jam the downlink frequencies on various cellular telephone systems. Prevents the cellular phone user from sending or receiving phone calls within the small jam radius. Advanced electronic and RF engineering technical skills will be required. http://gbppr.dyndns.org/PROJ/mil/cel...l_jammer-3.png http://gbppr.dyndns.org/PROJ/mil/celljam/pcs_jammer.png Links to a couple of schematics on the site. Try the main site http://gbppr.dyndns.org/ and follow the link to projects then scroll down to cell phone jammers Have any special software running? I can access it with web washer running, set for maximum privacy - no cookies, no web bugs, no refferer. I'm in the US -----= 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! =----- |
mobile (cell) phone jamming
On Sat, 20 Dec 2003 07:46:24 -0000, Jon
wrote: If Mr bush said "would you mind turning off your network for a few hours" and the network said "yeah, OK" I think you'll find that what would have happened is that Mr Bush asks them to turn the networks off, and the networks respond "Off? **** off!" -- Iain the out-of-date hairydog guide to mobile phones http://www.hairydog.co.uk/cell1.html Browse now while stocks last! |
mobile (cell) phone jamming
wrote in message
... On Sat, 20 Dec 2003 07:46:24 -0000, Jon wrote: If Mr bush said "would you mind turning off your network for a few hours" and the network said "yeah, OK" I think you'll find that what would have happened is that Mr Bush asks them to turn the networks off, and the networks respond "Off? **** off!" Iain Didn't Tony give himself powers to turn off GSM networks after the fuel strike. Steve Terry |
mobile (cell) phone jamming
On Sat, 20 Dec 2003 20:18:07 -0000, "Steve Terry"
wrote: Didn't Tony give himself powers to turn off GSM networks after the fuel strike. There have been those powers for a very long time. -- Iain the out-of-date hairydog guide to mobile phones http://www.hairydog.co.uk/cell1.html Browse now while stocks last! |
mobile (cell) phone jamming
default wrote:
snip Whenever I try to hit that site i get: Forbidden You don't have permission to access /PROJ/mil/celljam on this server. What's the story? Devices to jam the downlink frequencies on various cellular telephone systems. Prevents the cellular phone user from sending or receiving phone calls within the small jam radius. Advanced electronic and RF engineering technical skills will be required. http://gbppr.dyndns.org/PROJ/mil/cel...l_jammer-3.png http://gbppr.dyndns.org/PROJ/mil/celljam/pcs_jammer.png Links to a couple of schematics on the site. Try the main site http://gbppr.dyndns.org/ and follow the link to projects then scroll down to cell phone jammers Have any special software running? I can access it with web washer running, set for maximum privacy - no cookies, no web bugs, no refferer. I'm in the US It still wont let me in, i have a feeling it's being blocked by internal affairs. Howsabout emailing the png files to me...that'd be appreciated. -- Peter E. Lowrie ---------------------------------------------------------- |
mobile (cell) phone jamming
default wrote:
snip Can anyone point me in the right direction for designing this? http://gbppr.dyndns.org/PROJ/mil/celljam/ Whenever I try to hit that site i get: Forbidden You don't have permission to access /PROJ/mil/celljam on this server. What's the story? I know the site is slow - sometimes there's just a blip every few seconds on the download meter - othertimes it works normally. Can you hear me now? No. Good. Devices to jam the downlink frequencies on various cellular telephone systems. Prevents the cellular phone user from sending or receiving phone calls within the small jam radius. Advanced electronic and RF engineering technical skills will be required. http://gbppr.dyndns.org/PROJ/mil/cel...l_jammer-3.png http://gbppr.dyndns.org/PROJ/mil/celljam/pcs_jammer.png Links to a couple of schematics on the site. Try the main site http://gbppr.dyndns.org/ and follow the link to projects then scroll down to cell phone jammers Have any special software running? I can access it with web washer running, set for maximum privacy - no cookies, no web bugs, no refferer. I'm in the US -----= 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! =----- Another idea would be to post the images onto alt.binaries.schematics.electronic -- Peter E. Lowrie ---------------------------------------------------------- |
mobile (cell) phone jamming
Tarapia Tapioco wrote in message ux.it...
I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. It would be better if it had some directionality but not too much. I don't want to aim it at someone but it would be nice to be able to disconnect the loud phone user in front of me without affecting the text messager behind me. Can anyone point me in the right direction for designing this? I'll assume that you realize doing something like this is a non-trivial violation of federal law. Last time I checked, malicous interferrence with federally licensed communications could earn one a $10,000 fine, 10-years in prison, or both. Cell phone jamming now already takes place in numerous facilities like hospitals, theatres, restaurants, and other venues (quite thankfully), but there it's confined to private property. Even then, it will likely be shown by the ACLU or some other leftist group to be an encroachment on existing communications law. Harry C. |
mobile (cell) phone jamming
On Sat, 20 Dec 2003 08:54:16 -0500, default wrote:
On Fri, 19 Dec 2003 21:44:04 GMT, Bob Stephens wrote: On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote: Tarapia Tapioco wrote: I want to build a mobile phone jammer * short range (not more than 5 yds) * handheld, small * battery powered so that when I'm on the bus/train and some idiot start loudly talking about his business, I can press a button and cause just enough interference to disconnect him mysteriously. What's the problem? If someone annoys me too much with a phone, I just offer to jam it somewhere. Manually. ;-) When someone annoys me by yakking on a cell phone in a restaurant, meeting etc., I just join right in the conversation "Sure thing Bill. Friday's great. Just don't bring that whiny annoying wife of yours..." etc. I get some priceless looks. Bob Hey that's pretty good - worth a try. Now, what is your technique for getting the woman on the road in the SUV who is ambivalent about which lane she intends to use? -----= 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! =----- Well I live and drive :( in Los Angeles.... I could probably handle lane ambivalence. It would be a step in the right direction for the SUV set out here. What we have approximates Brownian motion! -Bob |
mobile (cell) phone jamming
"DaveC" wrote in message
al.net... On Tue, 23 Dec 2003 10:45:30 -0800, starwars wrote (in message ux.net): "Ken Taylor" wrote: "Paul Burridge" wrote in message ... On 21 Dec 2003 13:11:20 -0000, er (Italy Anonymous Remailer) wrote: Well, the OP did say he wanted a maximum range of 5 yds inside a bus. Anyone know what sort of wattage that works out to? I suspect we're talking about a few mW. Or less, even. What power level do those car lock r/c key fob thingies work at? That ought to give some sort of indication. Why would it? The applications are totally different. I agree. The car lock remote uses infrared (I think) and transmits a very specific signal that the car receiver detects. The jammer would use cellphone frequencies (around 9GHz and similar bands, I think) and would need to transmit--I think--white noise across the target band, strong enough to drown out the signal the phone is already receiving. No. The car alarm/autolocking remote controls use RF, not IR. Simply arm or disarm your car alarm (you *do* have one, don't you?) from inside your home to prove this. Those owners who "point" the remote control at the car, haven't a clue how they work... -- DaveC I agree about the RF in the car locks, and, also, cell phones aren't (yet) at 9GHz(!). 900/1800/2400MHz generally. However they are pretty robust from an RFI perspective (dependant on cell system). The key lock would probably be a lot easier to jam. Anyway, all this begs the question - who the f**k do these people who want to jam/ban cell phones on buses and restaurants think they are? If I'm talking to the person next to me, is that okay? If I'm still talking to them, but over the phone, is that still okay? (Dumb maybe, but okay?). What's the difference whether I'm talking to a person in the flesh or via a piece of plastic and metal. At the cinema or theatre - sure. But who the hell is making these rulings about what's socially acceptable? Ken |
mobile (cell) phone jamming
I read in sci.electronics.design that Ken Taylor
wrote (in ) about 'mobile (cell) phone jamming', on Wed, 24 Dec 2003: What's the difference whether I'm talking to a person in the flesh or via a piece of plastic and metal. It's not the phoning that's annoying, it's the loud voice, which is quite unnecessary but we've got used to it through using ordinary phones. Ordinary phones have 'sidetone' anyway - you hear your own voice in the earpiece and that helps to control your own voice level. Mobile phones DON'T HAVE SIDETONE, which is a bit of a surprise when you first realise it. WHY they don't have it, I don't know; maybe the small dimensions mean that a usable level of sidetone results in acoustic feedback. But a mobile with sidetone might eliminate the annoying VOICE LEVEL. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! |
mobile (cell) phone jamming
On Tue, 23 Dec 2003 21:30:57 +0000, John Woodgate
wrote: I read in sci.electronics.design that Ken Taylor wrote (in ) about 'mobile (cell) phone jamming', on Wed, 24 Dec 2003: What's the difference whether I'm talking to a person in the flesh or via a piece of plastic and metal. It's not the phoning that's annoying, it's the loud voice, which is quite unnecessary but we've got used to it through using ordinary phones. Ordinary phones have 'sidetone' anyway - you hear your own voice in the earpiece and that helps to control your own voice level. Mobile phones DON'T HAVE SIDETONE, which is a bit of a surprise when you first realise it. WHY they don't have it, I don't know; maybe the small dimensions mean that a usable level of sidetone results in acoustic feedback. But a mobile with sidetone might eliminate the annoying VOICE LEVEL. Agreed. That's the nub of it. And there are still a lot of folks around who seem to think if the person they're calling is a long way away, they need to shout even louder! -- "I expect history will be kind to me, since I intend to write it." - Winston Churchill |
mobile (cell) phone jamming
"Paul Burridge" wrote in message
... On Tue, 23 Dec 2003 21:30:57 +0000, John Woodgate wrote: I read in sci.electronics.design that Ken Taylor wrote (in ) about 'mobile (cell) phone jamming', on Wed, 24 Dec 2003: What's the difference whether I'm talking to a person in the flesh or via a piece of plastic and metal. It's not the phoning that's annoying, it's the loud voice, which is quite unnecessary but we've got used to it through using ordinary phones. Ordinary phones have 'sidetone' anyway - you hear your own voice in the earpiece and that helps to control your own voice level. Mobile phones DON'T HAVE SIDETONE, which is a bit of a surprise when you first realise it. WHY they don't have it, I don't know; maybe the small dimensions mean that a usable level of sidetone results in acoustic feedback. But a mobile with sidetone might eliminate the annoying VOICE LEVEL. Agreed. That's the nub of it. And there are still a lot of folks around who seem to think if the person they're calling is a long way away, they need to shout even louder! Aint that the truth! I'll go along with that argument - discretion is such a poorly rated virtue. Ken |
mobile (cell) phone jamming
"Ken Taylor" wrote in message ... "Paul Burridge" wrote in message ... On Tue, 23 Dec 2003 21:30:57 +0000, John Woodgate wrote: I read in sci.electronics.design that Ken Taylor wrote (in ) about 'mobile (cell) phone jamming', on Wed, 24 Dec 2003: What's the difference whether I'm talking to a person in the flesh or via a piece of plastic and metal. It's not the phoning that's annoying, it's the loud voice, which is quite unnecessary but we've got used to it through using ordinary phones. Ordinary phones have 'sidetone' anyway - you hear your own voice in the earpiece and that helps to control your own voice level. Mobile phones DON'T HAVE SIDETONE, which is a bit of a surprise when you first realise it. WHY they don't have it, I don't know; maybe the small dimensions mean that a usable level of sidetone results in acoustic feedback. But a mobile with sidetone might eliminate the annoying VOICE LEVEL. Agreed. That's the nub of it. And there are still a lot of folks around who seem to think if the person they're calling is a long way away, they need to shout even louder! Aint that the truth! I'll go along with that argument - discretion is such a poorly rated virtue. And, for some reason, people on a phone forget they are in a crowd. Nothing like being in a public venue and having someone shouting into their phone, discusing someone stool sample (true story). |
mobile (cell) phone jamming
"George Orwell" wrote in message
... "Gordon Brown" . wrote: "Steve Terry" wrote in message ... You mix 45MHz with the phones own TX signal, from any phone nearby. Then retransmitting itself up 45MHz into the phones receiver. Whatever channel the phone is on, it's always a precise 45MHz diference Without the phones transmit signal all the jammer puts out is it's 45MHz osc What so difficult to understand ?? The difficult bit is adding the time delay so the phones TX time slots overlap it's own RX time slots, otherwise the phone simply won't hear itself, feedback, and stop working. Ah, I see, you mean a broadband jammer (otherwise it will not cope with two phones transmitting on different channels). For some reason I was assuming that it was some elaborate narrow band jamming device. Why not just transmit a burst of white noise at 950Mhz with a 45MHz BW? That's what I was thinking. This would be a lot simpler than having to detect a specific signal, modulate it by 45MHz an retransmit it. Would the white noise across the right frequency band confuse the phone enough to disconnnect or garble the call? Probably not. Particularly a CDMA system, unless you put out so much power that you were obvious to the crowd - the car battery, being up against a wall, being cavity probed by the FBI........ Ken |
mobile (cell) phone jamming
"George Orwell" wrote in message
... "Gordon Brown" . wrote: That's what I was thinking. This would be a lot simpler than having to detect a specific signal, modulate it by 45MHz an retransmit it. Would the white noise across the right frequency band confuse the phone enough to disconnnect or garble the call? I am no RF engineer, but IIRC, building a broadband transmitter intentionally is not that simple. Also the noise will have to be above the signal from the base station transmitter (say 50W transmitter?). I wonder if it would not be easier to jam the uplink signal as this would only require the jammer to transmit in the same order of power as the mobile. |
mobile (cell) phone jamming
"George Orwell" wrote in message
... "Gordon Brown" . wrote: "Steve Terry" wrote in message ... snip Ah, I see, you mean a broadband jammer (otherwise it will not cope with two phones transmitting on different channels). For some reason I was assuming that it was some elaborate narrow band jamming device. Why not just transmit a burst of white noise at 950Mhz with a 45MHz BW? That's what I was thinking. This would be a lot simpler than having to detect a specific signal, modulate it by 45MHz an retransmit it. A broad UHF input 45MHz mixer osc with broad UHF output is very simple to make Would the white noise across the right frequency band confuse the phone enough to disconnnect or garble the call? A broadband UHF white noise jammer would have to transmit very much more power to have an effect The whole point of the phone operating on a 45MHz split with odd phased time slots is so the phones RX doesn't hear it's TX. Upset any part of that cycle with a relatively low signal, and the phone stops working. Steve Terry |
mobile (cell) phone jamming
"Steve Terry" wrote in message
... The whole point of the phone operating on a 45MHz split with odd phased time slots is so the phones RX doesn't hear it's TX. Upset any part of that cycle with a relatively low signal, and the phone stops working. So what sort of delay would be necessary and to what tolerance? |
mobile (cell) phone jamming
"Gordon Brown" . wrote in message
... "Steve Terry" wrote in message ... The whole point of the phone operating on a 45MHz split with odd phased time slots is so the phones RX doesn't hear it's TX. Upset any part of that cycle with a relatively low signal, and the phone stops working. So what sort of delay would be necessary and to what tolerance? A few microsecs ? I would guess interfere with as little as 20% of the slots to stop the phone working If there is already a random element in the slots maybe just letting the phones RX see it's TX with a nearby 45MHz mixer osc could be enough ? Steve Terry |
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