Wireless Video Useful tools? Or Smoke and Mirrors?
Hi Guys. Good to see many of you at NATIA last month. For those of you who couldn't make it, there were plenty of attendees, more vendors than ever, and the usual good information, fellowship, food and entertainment. There were some new and genuinely useful products, many of the same stale ideas that haven't quite made it (but God bless them for trying), and the usual string of hopefuls, hobbyists, wannabees and mad scientists who add color to the profession. Looking forward to the 1995 conference in Sparks, Nevada. Call me if you want contact info (attendance restricted to government only).
Well, here's part two on wireless video systems. In part one last issue we discussed the basic concept of video transmitters, the legal aspects, FCC type acceptance, and the fact that most claims for operating range are exaggerated tremendously (and we learned why). We covered using antennas to try to extend range, why this doesn't always work, and how to get the most bang for your buck. If you don't have part one, call Al Menear at Police and Security News (215-538-1240) to get a copy.
Since the issue is so important, this month we'll discuss even more about the legal implications of video transmitters. We'll expose some blatantly illegal tactics on the part of several suppliers, and straighten out some misconceptions about the law. Remember, for other than federal agencies, the only type of video transmitter legal to use or possess (or advertise) is an FCC type accepted (license free) unit. 900 megacycle -- the most popular -- type accepted transmitters have an extremely limited range of typically 150 feet.
For purposes of the law, state and local police departments are considered consumers and are bound by the FCC type acceptance requirement. To use or possess any non type accepted unit is illegal, and any evidence gathered by its use is inadmissible under the fruit of the poisonous tree doctrine. In spite of this, most suppliers knowingly continue to offer illegal equipment to law enforcement. Don't be stung. Do your homework and ensure you purchase a legal system.
Federal agencies are exempt from FCC type acceptance requirements and are permitted to do pretty much anything they want. Equipment sold to the Feds (not type accepted, so illegal to other than federal guys) is capable of working well. Because of this, certain suppliers of otherwise illegal equipment try to hide behind a clause in their advertising stating their equipment is offered to federal agencies or for export only. All well and good, except these guys will sell to anyone who has the money.
There are certain specific situations in which non-federal agencies can get a license to use a video transmitter. Under CFR 47 part 90, non-federal law enforcement or public safety agencies can get a site license to operate video transmitters on 2.2 GHz - 2.4 GHz. These transmitters can operate at power levels up to 250 milliwatts (1/4 watt). Part 90 licensed systems must use directional antennas, but it is possible for law enforcement agencies to get a waiver to permit use of omnidirectional antennas. Manufacturers of this microwave equipment should be able to advise you in obtaining a site license for their products.
License free systems legal for anyone to use (state and local law enforcement, security firms, private detectives, amateur spies) fall under CFR 97 parts 15, 90 and 94. Part 15 generally refers to 900 MHz systems discussed in part one of this series, although there are other provisions for license free systems under part 15 we will cover later. Part 90 was covered in the previous paragraph. Part 94 concerns itself with broadcast systems used by news media and the like and have no application to law enforcement. Most of our discussions will involve part 15 systems.
A common misconception, possibly dating back to the early days of Citizen's Band (good buddy) walkie talkie type radios is transmitters with power levels below 100 milliwatts do not need to be licensed. None of this is true for any video transmitter. Do not allow a vendor to claim his system is license free or otherwise legal to use merely because of the low power level. This is especially of interest in systems which transmit on broadcast television frequencies.
A number of suppliers sell video transmitters which can be received on an ordinary television. WATEC sells one for approximately $1600 which transmits on commercial UHF television channels. This system and all others like it are absolutely illegal in addition to being extremely ignorant (keep reading) for surveillance applications and should not be considered.
Systems transmitting on commercial television frequencies may seem attractive initially because you do not need a dedicated, special purpose receiver to hear them. Prices can be as low as $50 for systems intended for consumer household use. Range of the $50 systems may be as impressive as 100 feet, but usually they will not penetrate even one interior wall. And, these transmitters are free running -- not crystal controlled -- which means their frequency will drift and performance will suffer as they warm up and the temperature changes. If you're unfortunate enough to be stuck with one of these, keep the power on all the time so the unit will stay warm and hopefully not drift too far off frequency.
Keep in mind, if you use a transmitter on broadcast frequencies, not only can your TV receive it, but so can hundreds of millions of televisions all over the country. Do you want to transmit your surveillance activities to every zoohead with a TV? Apparently this is what the suppliers of these devices want you to do when they offer "surveillance" transmitters to law enforcement. There was a well known case in Florida a while back when a local police department using one of these broadcast transmitters on a surveillance learned that dozens of guests in a well known hotel chain were watching a drug deal go down on the televisions in their rooms.
Apparently the supplier of the surveillance package thought the short range of their device gave it some measure of security against unwanted audiences. The supplier of the system they used did not tell the agency their equipment was transmitting on broadcast frequencies. The agency might not have known because the supplier had built a briefcase type system which hid the fact they were using consumer television equipment. Bummer. You must trust your supplier to look out for your interests, which generally means you should avoid spy shop type suppliers and basement hobbyists trying to break into the surveillance business. Do your homework, deal with recognized and reputable suppliers, and ask pertinent questions before purchasing equipment.
Jumping around a bit, let's get back to part 15 license free systems. There are 3 frequency ranges authorized under part 15 for video transmitters. The most common, and most practical, are 902 MHz - 928 MHz. There is another allocation at 2400 MHz - 2483 MHz, and one at 5.8 GHz. (GHz is an abbreviation for Gigahertz, which equals 1000 Megahertz. Incidentally, I bite my tongue a bit when I say Hertz, as this is a relatively new term meaning cycles per second. In my opinion, frequency should be measured in cycles, not bushels, cubits or rods. Hertz rents cars. If I unwittingly refer to X megaCYCLES, please mentally translate this to X MegaHERTZ, and humor an old buzzard.)
At higher frequencies like 2.4 GHz and 5.8 GHz (microwave), "path loss" is a serious detriment to range. The higher the frequency the greater the loss through the air between the transmit and receive antennas. A redeeming factor is antenna gain can be much higher in a practical physical size at high frequencies, and more gain will overcome path losses to an extent. Dish antennas are the thing at microwave frequencies.
But remember dish antennas are not covert, and must be used at both ends for best results. Merely improving the receive antenna will only help to a certain degree, as you can't receive what isn't transmitted in the first place. If your transmit antenna is very tiny for concealment reasons, there is a practical limit in how much you can make up at the receive end. A FCC type accepted transmitter (the only legal, license free type) by law must have a sticker attached bearing a manufacturer's ID and an FCC type acceptance ID number. A type accepted transmitter is only legal in the form submitted to, tested and type accepted by the FCC. As soon as you start monkeying around with antennas, packaging or reconfiguring, you've voided the type acceptance and have an illegal product. There are several suppliers who start with a legitimately type accepted device and then chop it up to package it in a number of covert concealments. First of all, the performance suffers when they do this, but more importantly, they advertise the covert package as a legal, license free device which it is not after they monkey with it. When evaluating products, do not merely take the manufacturer's word for it that a particular device is type accepted and license free. Protect yourself by asking for the manufacturer's ID and the type acceptance number. You should verify this with the local FCC office as there are quite a number of phony type acceptance stickers out there. A side benefit of the call to the FCC is they can give you the manufacturer's name and address, and you can call that manufacturer and purchase from him directly often saving the few hundred percent markup you will pay to a dealer.
And almost universally you will get better technical and customer service dealing directly with the manufacturer. Unfortunately, most suppliers of video transmitters do not know their product and are unable or unwilling to support the product they sell once your check clears. You should know there are only a small number of genuine manufacturers of video transmitters. Many resellers blatantly lie by claiming to manufacture the products they sell, but the FCC label with the manufacturer's ID will reveal the truth (on type accepted products). It is not too unusual for some spy shop or similar outfit to send us catalogs offering to sell us a product we manufacture.
To read the catalogs, they claim they build the things, but apparently they don't even know who the original manufacturer is, or they wouldn't be offering to sell our own product back to us. Their catalogs listing our products also tell us they don't have stock because we know where our products go when they leave here, and they don't go to spy shops. If they would get an order, they'd call their supplier who would call his, and so on up the line until somebody called us. We even saw a bit of this at NATIA last month, with firms thinking they were competing with us unknowingly advertising our products under their own name. Let them get an order (your order?) and see if they can fill it.
The moral of the story -- search out the original manufacturers. You're investigators. It shouldn't be difficult. You don't need to pay a big premium to a reseller just because he knows a source you don't. Of course, if he is adding value, is a regular supplier to your agency or the manufacturer sells only through a dealer network then it's OK. Be especially cautious of the new kid supplier on the block who popped up out of nowhere and is trying to break into the glamorous (yeah, right) world of surveillance by "selling to police". In sports and rock music we would call these guys "groupies". They may even have their own pair of handcuffs.
A scam very popular in the world of 900 megacycle video transmitters is to offer a legitimately type accepted product, but then modify it to be illegal when the customer complains the system has no range. There are at least two well known and apparently reputable firms doing this. As we discussed in part one of this article, a legal 900 MHz transmitter operates at such a low power level that is has a very short range. No matter what the manufacturer claims, a legal part 15 transmitter on 900 MHz will have a maximum range of 700 feet with large, elaborate receive antennas, and more typically 150 feet with practical antennas.
If a manufacturer claims significantly more range than this he either is lying or is illegal. The scam perpetrated by the two manufacturers mentioned earlier is to supply a legal device. If you complain and return it, they jump out a pad of resistors in the transmitter to raise the power from a legal one or two milliwatts to as much as 250 milliwatts. Of course the range will be greater, but the system is now illegal. I understand the FCC is pursuing this with test buys, and it will be interesting to see which manufacturer(s) quietly stop advertising after the FCC stings them.
I'm looking at an ad right now for a video transmitter I tore out of a security magazine last night. Their ad claims in large letters "Wireless Video That Really Works". They show a picture of a transmitter approximately the size of an index card apparently on about 400 MHz judging by the length of the antenna.
The caption below the picture reads "Audio Video Transmitter, 90 mile maximum range". Let's pause a moment for a reality check. A typical broadcast television station needs 50,000 watts, a tower so high it should be considered the 8th wonder of the world, an extremely high gain antenna network, and an investment of tens of millions of dollars in equipment to achieve a range usually quite a bit less than 90 miles. Yet here's a basement cowboy claiming a little hobby box will do the same thing. And the crime of it is people believe what they read and purchase these things.
I personally know three separate agencies who purchased one of these transmitters and after extensive experimentation were unable to get the systems to transmit even out of the room. The manufacturer's excuse? "Well, it works for everybody else. If you're technically incompetent that's your problem, not ours." Don't be so naive to believe somebody has made a "Surveillance Breakthrough" and violated the laws of physics. Perhaps the ad was a misprint and the supplier meant to say 90 feet instead of 90 miles. Somehow I doubt it.
I apologize for being so cynical. But I am writing this series of articles at the specific request of eleven law enforcement agencies who have been burned by the tactics mentioned above and have encouraged me to expose the situation and save you the same embarrassment. Anybody who takes offense at anything I've said here is probably one of the people who has been misrepresenting his products and ripping off innocent customers. I welcome comments from agencies and users on any aspect of video transmitters.
If you've been burned, don't roll over and play dead or you're just encouraging the suppliers. Demand your money back, complain to the magazines carrying their ads, and share your experiences with your peers. Conversely, if you have positive information useful to your fellow investigators, let me know and I'll share it (after I verify it, of course. I got a call last month from a guy claiming to work for the CIA telling me how wonderful a certain brand of video transmitter was. I had personal experience with the particular transmitter so I kept my mouth shut. When I got the bill for my 800 number, as I suspected the call was from the seller of the equipment).
COMING IN PART 3 -- Same bat time, same bat magazine: How ham radio equipment is being sold as surveillance equipment at 1000% markup. How miniature video systems intended for use in model airplanes are repackaged and sold as surveillance equipment. Some truth and much fiction regarding body worn video transmitters. The truth about multi channel video systems. What topics would you like to see discussed, either regarding video transmitters or other aspects of electronic surveillance? Call me (contact information below) or Al Menear at Police and Security News, 215-538-1240. As always, I enjoy hearing from you.
Copyright August 1994 by Steve Uhrig, SWS Security. All rights reserved.