terryb.bbs@shark.cs.fau.edu (terry bohning) (02/13/91)
Let us suppose you have an interest in interfering with a neighboring apartment's sound system. So when it's the FM, it's easy to hook an old Heathkit vacuum tube signal generator to an old car antenna and capture the receiver on that frequency (altho' more power on the 10.7 MHz IF would alleviate tuning the generator). But what about when it's a CD, tape, or album? Which would be better (easier, cheaper, more effective): inducing transients on the power line or radiating AF hash into space? Transients on the power line have to get thru the power supply filtering. Anyway, that runs the risk of damaging equipment, which is not the objective. Radiating AF hash seems like it may be better, but what is a good way to generate it? Would an old auto ignition coil hooked to a non-resistive spark plug and suitably triggered work well? Or is there an easier way? Technical responses only, please.
terryb.bbs@shark.cs.fau.edu (terry bohning) (02/14/91)
terryb.bbs@shark.cs.fau.edu (terry bohning) writes: > > Technical responses only, please. For those who have trouble with euphemisms and have sent me their opinions, let me rephrase the last line: "IF you have absolutely no knowledge of the situation, then keep your opinions to yourself". For those who have sent sympathetic messages and requested any useful technical info I might receive, I will happily comply.
dana@locus.com (Dana H. Myers) (02/14/91)
In article <FqBaX1w163w@shark.cs.fau.edu> terryb.bbs@shark.cs.fau.edu (terry bohning) writes: >Let us suppose you have an interest in interfering with a neighboring >apartment's sound system. So when it's the FM, it's easy to hook an old >Heathkit vacuum tube signal generator to an old car antenna and capture >the receiver on that frequency (altho' more power on the 10.7 MHz IF would >alleviate tuning the generator). Though Part 15 rules may allow the broadcast of a low power signal in the AM and FM broadcast bands, I'm fairly certain emitting RF to intentionally interfere with other radio services is ALWAYS illegal. So, technically, this is illegal. Emitting a powerful signal on 10.7 Mhz is *especially* illegal. >But what about when it's a CD, tape, or album? Which would be better >(easier, cheaper, more effective): inducing transients on the power line >or radiating AF hash into space? > >Transients on the power line have to get thru the power supply filtering. >Anyway, that runs the risk of damaging equipment, which is not the >objective. > >Radiating AF hash seems like it may be better, but what is a good way to >generate it? Would an old auto ignition coil hooked to a non-resistive >spark >plug and suitably triggered work well? Or is there an easier way? Hooking up a spark gap to an antenna does not just radiate audio frequency energy; it generates fairly broadband RF noise. In fact, some microwave sources are essentially a spark gap inside a tuned cavity. >Technical responses only, please. Technically? What you are discussing will generally interfere with much more than just an audio system. One sure fire approach is to generate a large amount of RF in close proximity to the system. In general, with few exceptions, doing this will technically be inconsiderate and illegal. The last time someone asked about this, we ended up in flame war. Just try to be an adult. -- * Dana H. Myers KK6JQ | Views expressed here are * * (213) 337-5136 | mine and do not necessarily * * dana@locus.com | reflect those of my employer *
richi@hpopd.pwd.hp.com (Richard Jennings) (02/14/91)
I suppose knocking on the door and politely asking the occupants to reduce the volume is out of the question? :-) richi. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - Richard Jennings, Software Development Engineer Pinewood Information Systems Division, the home of HP's Advanced Image Management System (HP AIMS), AdvanceLink, OpenMail and Multi-media communications Hewlett-Packard Nine Mile Ride Voice: (+44)/(0) 344 763738 ADMD=GOLD 400 C=GB Wokingham Fax: (+44)/(0) 344 763526 OU1=Pinewood ORG=hp Berkshire RG11 3LL E-mail: richi@hpopd.pwd.hp.com GN=Richard PRMD=hp England or: richi@hpopd.pwd.hp.co.uk SN=Jennings
robf@mcs213k.cs.umr.edu (Rob Fugina) (02/15/91)
In article <1991Feb13.224108.2823432@locus.com> dana@locus.com (Dana H. Myers) writes: >technically, this is illegal. Emitting a powerful signal on 10.7 Mhz is >*especially* illegal. > You've made me curious...why do you say *especially* illegal? Of what significance is that frequency? Me robf@cs.umr.edu
terryb.bbs@shark.cs.fau.edu (terry bohning) (02/15/91)
robf@mcs213k.cs.umr.edu (Rob Fugina) writes: > In article <1991Feb13.224108.2823432@locus.com> dana@locus.com (Dana H. Myers > >technically, this is illegal. Emitting a powerful signal on 10.7 Mhz is > >*especially* illegal. > > > > You've made me curious...why do you say *especially* illegal? Of what > significance is that frequency? > The significance is that this is the Intermediate Frequency of virtually every consumer broadcast band superheterodyne FM receiver in existence, If you broadcast on 10.7 MHz with enough power to hit the IF amps in the receiver, you will capture it no matter which station it's tuned to. I seriously doubt that it is any more illegal according to written law to xmit on 10.7 MHz than 1 MHz, but the fact is it create a lot more interference. The IF freq for consumer AM receivers (if anyone still cares) is 455 kHz.
lairdkb@mentor.cc.purdue.edu (Kyler Laird) (02/15/91)
In article <37340001@hpopd.pwd.hp.com> richi@hpopd.pwd.hp.com (Richard Jennings) writes: >I suppose knocking on the door and politely asking the occupants to >reduce the volume is out of the question? :-) Oh, c'mon! Part of being a computer nerd/EE geek is being advanced enough to avoid human contact by sending electronic messengers. How about a robot that seeks out loud noises and carries a big stick? ...or... Pick up one of the little noise alerts from Radio Shack (on sale now for only ~$5.00!!) - make a phone interface with your neighbor's phone number programmed for constant redial as long as the noise persists. ...or... Sneak into his apartment and put a BSR-X10 wall outlet in where he plugs his stereo in. (I did this once in a dorm - fun for a bit.) (Don't make me do smileys...) --kyler
dkazdan@cwsys3.cwru.edu (David Kazdan) (02/15/91)
I've always wondered how these became the standard IF frequencies, along with 50 KHz for the third IF in the older triple-conversion short wave rigs. Any history known here? --David, AD8Y
elmquist@nachos.SSESCO.com (Chris Elmquist) (02/15/91)
In article <37340001@hpopd.pwd.hp.com> richi@hpopd.pwd.hp.com (Richard Jennings) writes: >I suppose knocking on the door and politely asking the occupants to >reduce the volume is out of the question? :-) In my case it is-- since I've already done it at least a dozen times... and so have the police. I've written letters to the landlord of the adjacent condominium unit, complaining about the noise. The letters go unanswered. These people are intentionally obnoxious. The rest of the residents in this condominium building are as frusterated as I am and now I'm going to do something about it. If their TV and radio are unusable-- the hope is that they will move away. -- Chris Elmquist, N0JCF Internet: elmquist@SSESCO.com AMPRN: N0JCF@WB0GDB.MN.USA.NA BellNet: (612) 785-3516
smithj@hpsad.HP.COM (Jim Smith) (02/16/91)
I think the solution to your problem already exists in previous posts to sci.electronics: Just build the nuclear weapon which was outlined recently, and, in order to get away before it explodes, use the cheep one-time-only delay circuit which was also discussed recently. The resultant electromagnetic pulse oughta knock out the guy's stereo just fine. :-) Seriously, though, you say that if we don't know the particualar situation's details, we shouldn't comment. Well, I wouldn't want to assist someone in committing an act of criminal aggression without at least an explanation. (I've been watching CNN too much! :-) ) I think what you're trying to do is impractical anyway. If you really want to take out the guy's stereo, put 440V on his power line for a while. :-)
elmquist@SSESCO.com (Chris Elmquist) (02/17/91)
Thanks to all who responded with both the legal and moral issues surrounding this discussion. I guess my posting reflected a fit of emotional disfunction when I implied that I intended to jam my neighbors radio and TV reception. It's a most frusterating situation and when several postings suggested knocking on the door (something that has been exhaustively attempted) my fuse blew. I do not condone illegally transmitting on frequencies for which you are not authorized. I would stand to loose my amateur license as well as possibly going to jail. It's not worth that much to me just to get even with these jerky neighbors. As many e-mail responses indicated, there are plenty of other ways to approach this problem. I like the idea of a sound absorbing barrier against the offending wall-- I'm going to pursue this approach rather than the RF one. End of "re: audio jamming" for me... Chris
terryb.bbs@shark.cs.fau.edu (terry bohning) (02/17/91)
Summary of possible ECM against offensive audio sources: This summary is for informational purposes only. Intentionally interfering with licensed broadcasts or broadcasting at all without the appropriate FCC license is illegal. For FM and TV broadcasts, a signal generator or other RF source which is tuned to the appropriate frequency and suitably coupled to space (ordinarily via an antenna) may be used. If adequate power is available, broadcasting on an IF frequency would alleviate the need for manually tracking the receiver frequency. Broadcast band FM receivers ordinarily use an IF of 10.7 MHz, TV receivers use a picture IF of 45.75 MHz and a sound IF which is 4.5 MHz below that, at 41.25 MHz. TV receivers built before 1950 or so use a picture IF of 25.75 MHz. Broadcast AM receivers use 455 kHz as the IF freq. Direct audio sources (tapes, CD, albums) are tougher. Because of equipment complexity, size, and power levels, it's difficult to get an audio wavelength propagating. In any event, the offensive source has nothing to act as an antenna except perhaps a long run of speaker wire. This would *really* require a lot of power. A possibility appears to be a CB radio. Consider a common emitter transistor stage in an audio amp which has a lightly bypassed or unbypassed emitter resistor. Then the base-emitter junction (diode) and the emitter resistor in conjunction with the bypass cap (or the capacitance to ground of the subsequent stage) form a classical AM detector circuit. There are of course many other potential AM detectors in an audio amplifier chain, including IC's and FETs. If this method is effective, it can of course also be used against RF sources, since these are ultimately converted to baseband (audio). CB radios are cheap and widely available. Experimentation with power levels may be required. In the mid to late 1970s, linear amplifiers were available from many CB shops. These usually consisted of Horizontal Output Tubes from television receivers of the day connected in a grounded grid configuration. For each tube in the unit, about 50 to 75 W of power was obtained. A lot of older 10 meter amateur gear has been converted to run on 11 meters (CB band = 27 MHz). Many of the aforementioned linears were designed to run on 10 meters, but came with instructions telling which components *not* to change to allow the unit to run on 11 meters. Conveniently, a small bag of said components was also supplied. Some higher power linears (500W up) simply had straps across several turns of the air-core coils in the unit. Cutting these straps retuned it to 11 meters by increasing inductance in the tank circuits. Lower modulation freqs may work best so they don't get bypassed to ground. CB channels have a 6 kHz bandwidth, so the transmitters limit the highest modulating freq to less than 3 kHz anyway, usually with a fairly obvious filter. If the modulation freq were 60 Hz, even a knowledgeable listener might believe it to be an equipment malfunction and perhaps remove the offensive unit for a trip to the repair shop. Voice modulation is ordinarily inadvisable. Lastly, note that very little, if any, CB gear is rated for continuous duty. One suggestion has been to induce transients on the AC line by interrupting a large inductive motor with an SCR. Obviously, if the transients are sufficiently large and/or fast, expensive equipment may be destroyed. Furthermore, such transients would be totally indiscriminate in whose equipment and which equipment would be affected. In addition, it is unclear whether these transients could be coupled through the pole transformer and beyond or not. Also, turning a piece of equipment off does not necessarily protect it from line transients, so the consequences could be very far-reaching. Implementing this action would violate more than FCC regulations, and would leave the implementor open to criminal prosecution and legal action.
gil@limbic.ssdl.com (Gil Kloepfer Jr.) (02/21/91)
In article <332@nachos.SSESCO.com> elmquist@SSESCO.com (Chris Elmquist) writes: >I guess my posting reflected a fit of emotional disfunction >when I implied that I intended to jam my neighbors radio and TV reception. I wouldn't agree with this. Although I don't think it's necessarily a good idea, I can see where one can easily be driven to this extreme. >As many e-mail responses indicated, there are plenty of other ways to >approach this problem. I like the idea of a sound absorbing barrier >against the offending wall-- I'm going to pursue this approach rather >than the RF one. I have two problems with this idea: will the barrier absorb the thump-thump-thump that dingbats of the genre described generally emit by cranking the bass as well as the volume, and who is going to pay for this sound barrier? I find it hard to swallow that there isn't more that can be done with inconsiderate folks like this. I know, life isn't fair...but everyone has certain buttons. I'm not condoning the practice of RF pollution to get even with the neighbors, but question how to cost-effectively deal with the *noise* pollution eminating from the neighbor's place. I realize this discussion does fall outside the realm of electronics, but perhaps that there's an electronic solution (or catalyst) that could help solve the problem. -- Gil Kloepfer, Jr. gil@limbic.ssdl.com ...!ames!limbic!gil Southwest Systems Development Labs (Div of ICUS) Houston, Texas "There are beautiful people I wish would have never opened their mouths, because such ugliness oozes out." Philosophy Prof. at NYIT
limey@cs.mcgill.ca (Mark ORCHARD-WEBB) (02/21/91)
This little debate has brought back the memory of a most enjoyable solution I found to a similar problem. The method I used to retrain a loud neighbour was to install a pizoelectric transducer in his ceiling (he was directly below me, it often seemed he kept his LS lying on their backs as in the Beethoven's 5th torture scene in Clockwork Orange) These transducers can be capable of 100dB SPL at high frequencies. The transducer was hooked upto an amplified oscillator at around 17KHz. When the offending music becomes intolerable turn it on. The beauty of it is that due to the already high SPL in the guy's apt he does not appreciate it as a foriegn sound but rather as pain (I find the sensation somewhat of a creeping pressure on the scull). I having 6 inches of wood flooring was reasonably isolated from the high frequency but he was only 1 inch of plaster away from it so it was quite effective. Better yet he seemed to think that it was his sound system at fault since I saw him hauling various parts out on different occasions after the retraining began. Eventually I hooked the thing up to respond linearly to the SPL in my apt while I was away. Sure enough after a few months, as with the little white rat, my neighbour learned that socially deviant behavior was related to pain and his behavior was modified. A few notes: The frequency of the oscillator should be just above the range where it is an identifable sound just a sensation. Please do not do this around animals I am sure that this will cause them much more distress than the original noise. Mark, (sometimes refered to by fellow physists as pscho.)