Disclaimer: This is meant as an examination of domestic SIGINT and ELINT sources, not as a primer on how to spy on one's neighbors. The reader is reminded that it is a felony in United States to monitor communications without specific legal authorization to do so, in other words unless you have a warrant for this sort of thing you are breaking the law. Furthermore, possession of equipment capable of receiving cellular phone transmissions is a violation of U.S.C. Title 18 and a violation of FCC regulations governing the capabilities of radio equipment. Modification of said equipment is also a felony and covered in gory detail in Title 18 of the United States Code.

Introduction
Insecure domestic emitters are quite possibly the largest threat to privacy, perhaps second only to the monitoring of e-mail or data transmissions from a residence. The proliferation of transmitters such as cellular and cordless phones, constant transmission radios (baby monitors,) and Family Radio Service devices have presented a serious threat to in home security. Information over the topic of frequencies used by VHF cordless phones is readily available on the Internet and welcome for use by anyone in possession of commercially available radio equipment. Despite contrary belief, VHF RF energy is quite persistent and will continue for quite some way until stopped by a major land feature. (The NSA, DIA, and CIA have all used satellites to monitor domestic UHF/VHF communications inside of target countries. Domestic intelligence collection is something of a sticky subject on which the government will not publicly comment. The capabilities are certainly there, however.) Therefore, with moderately priced communications equipment it is not at all unreasonable to expect some amount of unauthorized monitoring to be conducted by private individuals.
Most readily available models on the open market that still have their factory frequency cut-outs installed (usually the cellular band from 815-900 MHz,) are still capable of receiving FRS (Family Radio Service) and cordless phone FM transmissions. FRS is of particular concern given that parents often will give children these small handheld 'walkie-talkies' (Motorola Talk-Abouts are an example of such a device,) as a method of keeping in contact with them. These units are capable of transmission over a matter of miles in some cases, which could present a significant threat to child safety should the wrong individual be listening at the wrong time. 900 MHz and 1 GHz cordless phones broadcasting inside the cellular band will stop most casual monitoring, however these have yet to become popular probably due in large part to the expense involved in purchase. However, cordless telephones with their base station frequencies between 43.720 MHz - 46.970 MHz and their handsets operating at 48.760 MHz - 49.970 MHz are well within the range of almost all unmodified equipment. Given that 'baby monitors' also operate at the same frequencies (the upper half of the cordless phone frequency range,) it is possible to monitor a number of insecure domestic transmitters with little difficulty. AOR, Icom, Sony, Uniden, Radio Shack, Motorola and Yaesu all manufacture receivers capable of receiving these frequencies.

Are They Watching Me? Detecting a Collection Attempt.

Collection will more than likely begin passively, meaning the subject will not be aware of monitoring until an overt action is undertaken by the observer. This may include domestic violence, theft of personal property, identity or credit card theft, stalking, telephone or physical harassment. During a concerted effort at collection the subject individual may notice a vehicle parked in a specific spot for extended periods of time, where a considerable amount of the interior cannot be clearly viewed from the outside. Also of note would be the theft of refuse from curbside containers awaiting collection, missing mail or RF/electronic transients heard during phone conversations in the case of physical (hard) phone taps. Individuals living in close proximity to the residence with suspicious antennae projecting from the structure or caught in blatant observation of the subject residence would also be clear signs that a collection effort is underway.
If the observing party is a professional or has some knowledge of covert operations then it can be assumed that a collection attempt will not be detected unless a serious mistake is made on the part of the observation team. More often than not, the subject under surveillance has some awareness that they are being 'watched' and have done something to merit such attention. Obviously, this does not cover professional collection as this will more than likely be conducted at a national (e.g. government sponsored,) level with resources far beyond the reach of the average citizen.

Professional and amateur surveillance.
The delineation between professional and amateur surveillance made here is a significant one. For reasons of clarification, the following can be said of the difference between the two. Amateurs such as local law enforcement, private individuals and non-law enforcement organizations (i.e. private investigators and that ilk,) usually commit grievous errors that are easily detectable by a casual observer. Local law enforcement is known for typically providing credible and obvious evidence that a collection effort is underway, such as physical surveillance and the usual make/model cars following an individual from place to place. If the individual believes that he or she is under surveillance, then they probably are. The next step lies in determining who or what organization is conducting the campaign and with what fervor the data collection is being conducted.
Professional surveillance is conducted at the national level by organizations such as the NSA, FBI, CIA, DEA, DIA, INS and local subdivisions thereof. The subject under surveillance is likely to detect a campaign being conducted by any DOJ (Department of Justice,) entities as they are subject to the same restrictions as local law enforcement. Information gathering by a component of the national intelligence infrastructure will likely not be detected without serious study or prior training by a private individual. The obvious resource gap between the average citizen and the federal government is the primary separating factor between amateur and professional surveillance. Hostile corporate surveillance can also be classified as professional surveillance.

Physical signs to be aware of in detecting a collection attempt
-Vehicles parked consistently in one spot, usually large vans with maintenance logos on the side that do not correspond to any local business. Can also be uniform in color, typically white.
-Specific individuals observed trailing the subject in question constantly enough to merit question.
-Transients in telephone equipment indicative of circuit interruptions, sudden decreases or increases in volume, technical problems that 'fix' themselves.
-RF interference with commercial computer or audio/visual equipment.
-Discrete RF transmitters found inside of furniture.
-Suspicious phone calls inquiring as to the physical status of specific individuals.
-Theft of refuse or personal property.
-Small scratches or slight damage to door locks on residence or private vehicle indicating an illicit entry attempt. This can also be indicated by 'sticky' locks that previously moved freely.
-Sudden alterations in mail traffic to a private residence. (Missing bills or other postal material.)
-Personnel with uniform haircuts or clothing observing an individual from a discreet (although close) distance.
-Vehicles consistently turning or changing lanes with another. (Multiple vehicle trails are also a possibility to be considered.)
-'Staged' intrusions into the home for the purpose of 'fixing' appliances that are not broken. (This includes sudden religious visits by various institutions that had not previously occurred.)
-Neighbor complaints of loitering by specific individuals in front of or near a residence.

Everyone is under surveillance! Echelon, Tempest, Satellite Surveillance and the Major International Collection Effort

Echelon
Echelon is a network of monitoring satellites and ground station scattered around the world that feed intelligence through Pine Gap, Australia to the American National Security Agency. There the information is washed through a program known as Semantic Forests, developed by the British Secret Service and Oxford University. The program then utilizes a series of Baysian logic routines (based on the work of Rev. Bayes from which they take their name,) to make semantic differentiations between varying forms of speech.
Saying to Joe that 'Paul Oakenfold is da bomb' will not set off a flag with Echelon, however telling Joe that 'I have da bomb and I want to blow up Paul Oakenfold' will garner immediate attention. (At least from certain progressive house sympathizers.) The significance of Semantic Forests lies in the ability of the system to rapidly interpret and disseminate collected intelligence with little operator interference, while still cataloguing necessary information for later examination. Private individuals are usually not the subject of serious study by Echelon unless they have come to the attention of the American, Australian and British intelligence apparatus. This system itself is remarkable since the information is released almost equally to all three governments except in cases when the U.S. National Security Agency decides that a piece of intelligence will not leave the United States. All three nations have both used Echelon generated information in planning integrated special operations (SPECOPS.)
There are some indications that the SAS sponsored takedown of Gerald Bull (designer of the world's largest artillery piece, the so-called Iraqi 'Supergun,') was planned with information culled from Echelon. (Note: Interestingly enough I had a conversation with an individual driving one of the vans in Melbourne, Australia when I was there. He referred to it as 'That Place' and laughed knowingly most of the time.)

Tempest
More of a rumor than fact, Tempest is supposedly a system capable of receiving radiated signals from such devices as computer keyboards and monitors for the purpose of domestic surveillance. Currently, no data is available concerning Tempest capability or function other than simple descriptions readily available from various underground web sites. This certainly would be a significant achievement in receiver design, given that it would have to sift through 60 Hz transients coming out of standard household wiring, solar radiation, and RF noise from stereo system components/wiring. Certainly this would not be all of the possible sources of interference, but enough that a powerful subwoofer would dictate that the antenna could be located no further than eighteen to thirty-six inches from the source. Any equipment capable of doing something of this nature would also have to have a directional antenna so focused that it could possibly be rendered impractical due to size and weight. Despite the fact that Tempest is a system straight out of science fiction, persistent rumors of stealth planes were later proven as truth. The expense of such a device with capabilities similar to Tempest would more than likely be beyond the budget of any organization save a national entity or major corporation.

Satellite Surveillance
With the declassification of some details of the KH-11 (under Project BYEMAN with codenames KENNAN and later CRYSTAL,) the deorbit of the last KH-8 (KEYHOLE) and KH-9 satellites come a new generation of imaging satellites. KH-13 (details as to project and codename publicly unavailable at this time,) and KH-11 (CRYSTAL) imaging satellites are in essence the equivalent of the Hubble Space Telescope turned the opposite direction. Obviously, with the resolution and quality of imagery coming from the Hubble instrument, it is not unreasonable to believe the somewhat fantastic claims that KH-11 and KH-13 satellites are capable of reading individual lines of newsprint.
In the case of the KH-8 and KH-9 satellites, canisters of film were dropped from the satellite for later retrieval by specially equipped C-130 Hercules from either the U.S. Navy or Air Force. Impractical to an extreme, nonetheless an interesting workaround to a difficult problem of retrieving stored data. Both the KH-11 and KH-13 satellites digitally transmit stored information to ground stations eliminating the need for complex film retrieval operations. Data can either be transmitted through the SDS (Satellite Data System,) or through the DSCS (Defense Satellite Communications System) network which is a network of geosynchronous spacecraft similar to the GPS system. Currently KH-11 satellites are widely operated by the national intelligence infrastructure, again details as to the nature, geometry and control of the KH-13 are currently unavailable.

Stop Staring at Me Like That. Defeating Domestic Collection

Stopping collection after it has begun can range from the difficult to the nearly impossible. For starters, the cessation of cordless phone use will significantly contribute to the denial of amateur surveillance and information gathering. Other likely sources of domestic surveillance such as FRS transmitters and baby monitors should also be eliminated as necessary to prevent third party monitoring of domestic activities as required. Certainly, a small amount of awareness as to the possible presence of domestic collection will contribute a great deal of assistance to the casual citizen with regards to personal privacy.
As private individuals, we should take it upon ourselves to safeguard personal information such as credit card numbers and so forth. The extreme case of pulping all of one's receipts and so forth with a blender and a large quantity of hot water should remain just that, the end of the line.
If you are currently the subject of surveillance by component of the international intelligence community, I would strongly encourage you to contact the appropriate organization (usually the FBI,) or cease whatever it is you are doing to warrant this attention. Cases such as the maudlin and melodramatic one put forth in the movie 'Enemy of the State' are nothing more complex than overblown Hollywood paranoia filmmaking at it's worst.

Personal Security
Instituting a medium of personal security will ensure that domestic surveillance ceases or does not start in the first place. The use of conventional phones, well secured garbage containers and the shredding of private documentation will place a severe burden on an individual seeking to collect data concerning a specific person. Living as a shut-in is obviously not an option, therefore the necessary steps should be taken to ensure security. Even going as far as to be aware of who one's neighbors are will contribute to this security, as they are more likely to report suspicious behaviors you do not see.

On the Road Again
Vehicular-based surveillance is less simple to defeat in that it requires practice and a keen observational eye to watch for necessary changes while in traffic. In the event that you determine that you are being followed find an off ramp in a well-lit neighborhood and circle the block several times. If the automobile is still there go to a drive up window, order some food for both yourself and your new friends (pay for both yourself,) and this will probably be enough of an embarrassment to discourage future tailing. (This actually works, don't ask how I know, just understand that it is very funny and works spectacularly well.)
Taking random routes to and from work with daily variation will also prevent vehicular surveillance, as you are likely to see the same car two or three lengths behind for several days in a row on different roads. This will force the person or persons responsible for the surveillance to either rent a large fleet of cars or cease tailing you. Given that if the subject is dealing with a government entity, they are not going to stop until their curiosity has been satisfied.

Residential Security
Finding a 'bug' in a residence is a fairly good sign (note sarcasm,) that either you or the previous resident was under some form of serious surveillance. If you are currently involved in an illegal activity of any kind then it is probably a safe bet that you are the one being watched. In this event, LEAVE THE BUG WHERE IT IS. Do not attempt to dispose of or remove the unit, place a tape recorder or CD player near the item and begin repeatedly playing the same song again and again. This will guarantee that the person(s) on the other end will become aware of the fact that you have found the unit and are not happy about it. The next step will either come in the form of a new unit or an attempt to retrieve and relocate the existing item.
It is a safe conclusion that if you find one there is a minimum of three others located inside the residence, possibly more. If you are the subject of hostile corporate surveillance, it is recommended that you contact your employer and ask them to deal with the situation. The correct installation and subsequent use of a passive alarm system is also an excellent way to defeat intrusions into the home.

Public sources:
The U.S. Intelligence Community, Third Edition. Jeffery T. Richelson 1995, pgs. 59, 151-153, 176-181, 217-220.
Practical RF Handbook. Ian Hickman 1999, pgs. 228, 294-295.
AVA(A1) Avionics Technician School Part 3/4 Class Notes/Materials: Yurei, 1993/1994.
Navy Education Electronics Training Series (NEETS) Modules 1-27: CNET, various, (Government Printing Office)
Icom IC-R3 and Sony ICF-SC1PC Communications Reciever Owner's Manuals. (Author Unknown.)
Various results of Excite search for the words: cordless, phone and frequencies.

Horsepucky! It's that dang Phase Maintenance at it agin'!