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From the Listening Post
Questions from readers and answers from a specialist on electronic surveillance and related topics


Hi all,
This time around we’ll answer a question and discuss wireless video. First, a touch of humor: 

Two atoms were walking down the street together. One stumbled and bumped the other, knocking him down.

“Oh my, I'm sorry”, said the one atom to the other. “Are you OK?”

“No, I seem to have lost an electron”, replied the second atom, as he was picking himself up off the ground.

“Are you sure?”, asked the first.

“Yes”, said the second. “I’m positive.”

You may laugh now.

Webmaster note: AArrgghhhhh!!!

Q – What if there were no hypothetical situations?

OK, now on to business.

A reader asks:

  • Steve, we’re not getting any usable performance from either of two wireless video systems we purchased largely based on my recommendation. The vendors haven’t been very helpful. Would a more powerful transmitter help as one vendor recommends? What else can I do to get these things to work as I was led to believe (one is on 2.4 Gigahertz and one is on 900 Megahertz)? We’re in a rural county and cannot get close in for observation by any other means. Appreciate any comments.  Sgt. Phillip S, — drug task force, southeast U.S.
  • Hi Phillip,
  • Welcome to the club.

    Some years ago I was teaching some wireless video classes at NATIA. In three sessions, I asked the same question, “How many of you are getting the performance the supplier of your (wireless video) system claimed you would?”

    Of approximately 200 attendees, not one raised their hand.

    The bottom line is: the claims for performance of essentially all wireless video are exaggerated.

    It’s a numbers game. Whomever quotes the biggest numbers wins. And the claims have grown exponentially, with everyone trying to outdo everyone else, to where one can only sit back and chuckle when reading the catalogs.

    Phillip, we can’t violate the laws of physics. Acknowledging that and working within their capabilities and limitations is the first step towards getting what you can out of wireless video systems.

    Here are some general guidelines and comments:

  • 1) 2.4 gig video is suitable for fixed point to point only. That means neither end is moving.
  • 2) Most wireless video, especially above 900 megacycles, needs a Line of Sight (LOS) path between the antennas. LOS means what it says. Nothing between the transmit and receive antennas other than atmosphere. Most wireless video penetrates anything (trees, walls, people, building structures) poorly. This is even more true at higher frequencies. Do not take LOS requirements casually.
  • 3) Since you’re gathering evidence, you especially need to be concerned with legal aspects. This will be discussed in more detail a bit later in this issue.
  • 4) In wireless video, almost all the work is done in the antennas. If you have good antennas, you don’t need power. Conversely, if you have poor antennas, all the power available probably won’t work.
  • 5) Reseller-type vendors generally have little or no concept of physics, communications, electronics or legitimate hands-on field experience with the products they peddle. They simply parrot each other’s words, generally embellishing them with every repetition. Don’t be afraid to ask questions and put them on the spot. This article will help you do exactly that.
  • 6) Vendors know very few people have the ability to measure claimed specifications, so get guarantees instead of empty promises, and enforce them. And ask pointed questions.
  • 7) Try to buy directly from manufacturers, not resellers. You’ll get better pricing and almost always better tech support. Manufacturers know their product. Most resellers literally have never seen, much less have used the products they sell/broker, especially in the field under a variety of real world conditions.
  • 8) Don’t be afraid to keep after your supplier if you’re not getting the performance you were led to believe you would. Ignore how much time has gone by since you purchased. If you’re not getting performance you expected, don’t let the vendor hide behind a warranty or especially a disclaimer.
  • 9) There is very little security on wireless video. Presume your transmissions will be monitored by ham radio hobbyists and buff types. Many articles have been published and the web is full of discussion on monitoring law enforcement video transmissions.
  • 10) All wireless video advertised as operating on 434 megacycles, or 4xx megacycles, is illegal for surveillance in the United States. Do not buy it. It’s illegal to use except for hobby purposes, license disclaimer notwithstanding even by federal agencies. For other technical reasons explained later, don’t use these freqs even if you’re outside the U.S.
  • 11) Federal agencies can NOT automatically use anything and everything anywhere. There is one limited exemption to the FCC Type Approval requirements for U.S. federal agencies. All other restrictions apply regarding frequency allocations, etc.
  • I’ll expand on the above.
  • Fixed point to point: If you need to link video between two buildings, like the local lockup to the courthouse for bail hearings, etc. (an increasingly common application, by the way, for better security and to save manpower and cost of transport), wireless video is fine. You can use higher performance antennas, which can be very directional, at no penalty.

    However, if either end is moving, like body worn, to or from a vehicle, you probably will not be a happy camper. Generally you cannot use directional antennas when one end or the other is moving, so you lose the performance benefit from them. Moving or non-permanent installations generally can not use large or decent antennas, and antennas are critical in making this stuff work.

    There are body worn video transmitting systems advertised. The transmitter is on the user’s body. Across the board these systems perform poorly and almost without exception are a waste of money. All the spy shop ads for covert cameras like pen and pager and button cameras may seem wonderful, but when they talk about connecting them to a video transmitter, they’re showing their ignorance. Stick to body worn recorders (a topic for another time) for body worn video applications.

    The human body absorbs so much signal at any frequencies used for wireless video as to render the concept useless at any practical power level. The commonly used frequency of 2.4 gigs is precisely the resonant frequency of water molecules, which is why if you look on the back of your microwave oven you’ll see the frequency listed as 2450 megacycles (2.45 gigs). This means any signal at 2.4 gigs to some degree will be cooking nearby human or animal flesh, which is something like 80% water. Proposing to use 2.4 gigs for body-worn systems is criminal insanity, and shows a total lack of understanding and disregard for the safety of the user. Important point: because of this characteristic of 2.4 gigs, do not use transmitters anywhere where a human will be in or near the path of the transmitted signal. The more powerful, the more damage. The closer to the transmit antenna, the more damage. The higher the gain of the transmit antenna, the more damage. Eyes and gonads go first. The FCC has exposure limits for stuff like this, which require a series of calculations using complicated formulae to determine safe levels.

    On a similar vein, microwave ovens interfere with the reception of 2.4 gig wireless video. Generally you will not be able to use a receiver near an operating microwave oven while the oven is in use. ‘Near’ usually means on the same floor if in a typical residence.

    Next point – the low power and high frequencies of most wireless video penetrates building materials, people, foliage, etc. poorly. Plan on a 75% reduction in range if you need to penetrate wood or concrete. Plan on a 95% reduction in range if you need to penetrate metal, like aluminum siding, foil backed insulation, or into or out of a vehicle.

    Legality – any non-federal agency in the U.S. must use FCC Type Approved (also referred to as Type Accepted or Type Certified – all the same; semantics only) transmitters. Note there are two classes of users: federal and all others. Local and state law enforcement are classified the same as Joe Sixpack citizen for purposes of the law.

    FCC Type Approval means the design of the system and usually a sample unit has been inspected by an FCC (Federal Communications Commission) laboratory, and found to be ‘clean’. Clean means within legal power limits, on the assigned frequency, not radiating any strange signals which may interfere with other users, not capable of being modified by the user to allow illegal operation and numerous other factors.

    FCC Type Approval is required of any radio type device, computers, etc. before they can be imported or sold in the United States. The full legal cite is too long to echo here, but email me if you’d like it and I’ll be glad to squirt it to you.

    In a nutshell, ignoring the technical aspects, a Type Approved device requires a label be attached to the outside of the device. The label must display the original manufacturer’s FCC ID number and the device’s FCC-assigned Type Approval label. Any device not displaying this label is illegal. Sounds stupid, but there are reasons. And a clever defense attorney will find a subject matter expert if he tries hard enough who will explain this to the jury and you lose.

    Now here’s the critical part – a device is Type Accepted in its original configuration. Any changes to the design submitted to the FCC, even something as small as the location of the antenna, or anything other than pure cosmetics like color of the plastic chassis, violates the Type Approval.

    Repackaging violates the Type Approval. Changing the antenna violates Type Approval. Even having an antenna which can be removed by the end user can violate Type Approval.

    I have never seen a single spy-shop grade (almost all of them) covert wireless video device like a wireless video clock radio, boom box, cell phone camera, etc. which has the mandated FCC label. And they’ve been repackaged from their original Type Approved configuration, if indeed they were Type Approved to start with. The spy shops seem to think once Type Approved, always Type Approved. Not true.

    Therefore, *all* these camouflaged video transmitters are illegal. You cannot use them to gather evidence. Any evidence you do gather is illegal and useless. The equipment is subject to confiscation and the user fined. Yes, the FCC  indeed can fine state and local governments. They call it ‘monetary forfeiture.’

    However, the spy shops claim these devices are license free and FCC legal. Not true.

    The FCC Type Approval number (if you can find one) can be researched on the FCC online database at www.fcc.gov. The first few characters are the manufacturer’s ID. By running a search of this number on the FCC database, you can learn the original manufacturer of your product. Most of the time it will be a Pacific Rim manufacturer, as very little consumer-grade wireless video is manufactured in this country. There are a few U.S.-based manufacturers who make excellent products, and I endorse a number of them. If you have a need for wireless video and are interested in reputable manufacturers, drop me an email and I’ll be glad to mention some good ones. On the same track, if you have a question about a particular supplier, feel free to ask me and I’ll tell you what I know about them. Please include a web URL so I can check their claims and give you a specific reply. I must acknowledge my company manufactures wireless video systems, but we sell outside the U.S. only and are not allied with any other manufacturers.

    While we’re on the legal issue, many suppliers, in every instance sleazy ones, offer equipment on 434 megacycles or other 4xx megacycle frequencies. Every one of these is illegal for surveillance. The 4xx frequency range is a U.S. amateur, or ham radio frequency band and can be used only by licensed hams for hobby purposes. No one way transmissions are permitted. No business or commercial use is permitted. All transmissions must be identified with your FCC-assigned amateur callsign after you’ve passed the technical, operational, legal and sometimes Morse Code exam. If you have an amateur license, you won’t care to operate illegally. If you don’t have an amateur radio license, applying power to these devices is illegal.

    Federal agencies do not have carte blanche to operate on amateur frequencies for any purpose other than legitimate coordination with amateur operators for emergency communications support, and even then all operators are required to have appropriate operator’s licenses. Theoretically federal agencies can get an IRAC coordination to operate nearly anywhere, but I’ve never actually seen this happen on amateur frequencies.  IRAC = Interdepartmental Radio Advisory Committee in the Office of Spectrum Management of the NTIA (National Telecommunications & Information Administration). Coordination is by frequency and location before operation.

    Be especially alert in advertising for a thin, useless disclaimer of ‘ARS License Required’ The term ARS was coined by spy shops and stands for Amateur Radio Service. They’re telling you their product is illegal. Do not buy anything claiming an ARS license is required. You cannot use it. And any vendor hiding behind this disclaimer deliberately is trying to mislead you. Consider that before doing any business with them for any products.

    Do not buy or use ham radio equipment. If you own any of these pieces sold under a pretext or disclaimer, request a refund from the vendor no matter how long you’ve had it. If they give you any static about this, simply tell them you’ll ask the FCC if what they sold you was legal for you to use and let the FCC take appropriate federal enforcement action. Contact me if you need a direct email address for the person at the FCC who enforces this precise issue. FCC Code Section 97.111 covers this if you want to check the precise wording for yourself.

    Even further, ham radio operators are electronic technoweenies who spend much of their waking hours endlessly tuning the bands listening for weak and interesting signals. I know because I’m one of them. They do this as a hobby and may have many hundreds of hours and frequently tens of thousands of dollars invested in their amateur stations. While they may indeed on rare occasions during band openings with towers, huge antennas and legal high power may realize ranges of dozens of miles for their amateur television signals, you’re not going to do the same thing with a pipsqueek transmitter and small antenna, especially in a covert installation. The claims for range on this stuff are exaggerated. What a dedicated hobbyist can do on occasion is not something you’ll do in the field, though the catalogs and websites lead you to believe differently. They don’t know the difference themselves. They read amateur catalogs and each other’s ads and think it’s all black box plug and play operation. Not true.

    Hams have better receivers and better antennas than you do, far more experience, and any signal you radiate on their frequencies sooner or later will be intercepted by them. You want low probability of intercept, not high. Additionally, amateur radio operators operate potent wide area coverage repeaters for video. It’s well possible the amateur piece you’re trying to operate covertly may trigger a repeater and retransmit your surveillance signal over hundreds of square miles. This precise scenario has happened numerous times, with a classic one in the Los Angeles basin. The hams rapidly located the source of the illegal transmission and took appropriate action.

    Speaking of which, no wireless video is immune to intercept due to the very large number of inexpensive consumer devices operating on these frequencies. There are a few video encryption devices offered, and I’ve played with them. Across the board they introduce more problems than they solve in real world situations. I don’t recommend them.

    To minimize probability of intercept, use the minimum transmit power needed to do the job and the best, most directional, highest gain antennas possible in your scenario.

    I’ll set aside all this cynicism and wrap up by saying there are legal, practical, effective applications for wireless video. A lot of bad guys have been locked up with proper use of the stuff. Don’t expect magic, do your homework, select a reputable supplier who preferably is the original manufacturer, discuss your needs with them and be conservative in what you expect to do and what you promise to your superiors!

    Feel free to ask me about technical or operational aspects of wireless video and I’ll be glad to assist you or steer you to someone who can.

    That’s it for this month. Thanks for the comments, questions and input. Please keep sharing your thoughts.

    Please address your questions on electronic surveillance technology, operations, hardware, etc. to:

    Steve Uhrig
    SWS Security

    Or call 410-879-4035, in Maryland, after 1PM weekdays for some live chat. I’ll acknowledge each message, try to assist, and with your permission may include my answers in this magazine.

    Copyright (c) Sept 2004 by Steve Uhrig, SWS Security.

    Steve Uhrig is the owner of SWS Security, an electronic surveillance manufacturing company located in Maryland.

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