A. Yes, as do many other things. The term “microwave” simply refers to radio waves at a frequency over about 1000 MHz (1 GHz). Cell phones, Bluetooth, Wi-Fi, cordless phones, baby monitors, satellite TV and radio, satellite Internet, and many other devices also use the microwave radio spectrum.

Q. Is there any risk to health from the microwave radiation in a fixed wireless  network?

A. No. The power levels and antenna placement of a wireless ISP network ensure that there is absolutely no risk to anyone from its microwave signals.

Q. Are there ever any risks to anyone from microwave radiation?

A. Of course. Exposure to strong microwave radiation can be risky. That’s how a microwave oven works, after all. And there are other sources of microwaves that are potentially dangerous if you are too close. That just doesn’t apply to what a wireless ISP does, though. The power levels differ by orders of magnitude.

Q. How much transmitter power will a fixed wireless network use?

A. All of the transmitters are subject to very strict FCC limits on power. None will have a transmitter power higher than one watt. Most will be lower, between a tenth and half a watt. For example, a point-to-point radio of the type that interconnects sites is allowed to transmit with up to 0.179 watt. That’s less power than a night light uses.

Q. How much power is that, compared to other personal radio devices and systems?

A. A cell phone transmits with a maximum power of one fifth of a watt (i.e., 200 milliwatts). A CB radio transmits with up to 4 watts. A police-type walkie-talkie can transmit at about the same power, which is still considered safe for its intermittent (push to talk) transmissions. So wireless ISP transmitters are all much weaker than a CB radio and various other “personal” devices, which are approved for use right next to your head or body.

Q. How much power do other fixed radio systems use?                    [Top of Page]

A. A cell phone base station will typically transmit with a power of about forty watts, and is subject to strict rules to keep people away from the antennas. A microwave oven generates about a thousand watts, in a confined space. A TV broadcast transmitter can generate over 100,000 watts. Some radar systems, like the ones used for weather forecasting, generate pulses with a power of over a million watts. Needless to say, those systems must be very carefully placed and protected! Hence the contrast with a fixed wireless Internet service, which only generates around the same power as something that is safe to hold in your hand, but which will still be kept far away from people.

Q. Is a fixed wireless Internet system the same as Wi-Fi?

A. No. Wi-Fi is aimed at local area use, primarily indoors. A fixed wireless system is outdoors. Parts of the system will operate under the same unlicensed power limits as Wi-Fi, but it is optimized for longer range use. ISPs may also offer Wi-Fi devices for indoor use, for customers who want private, secure wireless connectivity inside their homes. Or you can buy your own Wi-Fi devices elsewhere, or have no Wi-Fi at all and use only a wired connection to customer-premises radio, which will be outdoors.

Q. How much power does an indoor Wi-Fi system generate?

A. Wi-Fi is allowed up to one watt, and some systems use that, though typical home systems generally use about a tenth of that. But many office systems, and even some home systems, do come close to the full watt.

Q. Would a cable TV-Internet  system subject us to less microwave radiation?

A. Probably not. The amount reaching the inside of a house, or ground level, from a fixed wireless system is extremely low.

On the other hand, while a cable itself doesn’t radiate, Comcast’s current Wireless Gateway, their standard cable modem/telephone/Wi-Fi system, transmits indoors, on two bands, with nearly a full watt. That way it broadcasts its Xfinity Wi-Fi as widely as possible, and can also use Wi-Fi to distribute TV to rooms that aren’t wired for cable, using a Wi-Fi cable box. And unlike most Wi-Fi systems, the Comcast gateway doesn’t provide users with a transmitter power setting, though the Wi-Fi can be switched off.  A fixed wireless system, in contrast, is outdoors, and the home antenna is always pointing away from the house.

Cable systems also sometimes hang outdoor Wi-Fi access points from their cable. The cable companies are also going into the mobile business, using small cells attached to their cables or to poles in areas they serve. That reduces the amount of airtime they have to purchase from national mobile carriers.

Q. Will you be putting up a microwave tower?                   [Top of Page]

A. We will have one new tower, in Savoy, though it’s really just a fiberglass pole. All of the other vertical structures we will add are ordinary wood utility poles. They look nothing like big microwave towers or cell towers. They will not be more than 70’ high; most will be smaller. Height of the pole generally depends on the nearby tree cover.

Q. What about the antennas – don’t they make the signal more powerful?

A. A fixed wireless system’s antennas are all directional. What they do is focus the signal to put it where it is needed, keeping most of it away from where it isn’t, like downward, or at houses. This creates a higher “effective radiated power” (ERP) in one direction, while the ERP is lower in other directions. A cell phone’s antenna, in contrast, transmits in all directions (omnidirectional) – towards the base station, towards the user’s head, hand, etc.

The point to point antennas connecting the fixed wireless sites (poles) keep most of the power within a narrow beam, about five degrees of their focus. Therefore much less power radiates upwards, downwards, or sideways, compared to an omnidirectional antenna. The sector antennas connecting to users spread the power out over about 90 degrees horizontally, but again focus their power vertically within a narrow range. The signal strength at ground level, then, is less than what would come out of a cell phone or home Wi-Fi device at the same distance, even though the radios have a maximum range of several miles.

Q. How high up will your pole-mounted antennas be?

A. They will be in the upper reaches of the pole. The shortest poles with antennas on them will reach about 42 feet above ground, and the antennas will thus be at least 35 feet up. The tallest poles will reach about 70 feet, keeping the antennas at least 60 feet above ground.

Q. What will the home antennas be and how high will they be mounted?

A. The customer premise antennas will all be directional, point-to-point type antennas aimed at the serving site, and aimed away from the house. They will be always be placed where no one will be able to stand in their main beam, whether mounted to an upper wall or above the roof.

Q. How much microwave radiation will the customer premise antennas put into the home?

A. Virtually none. The walls of a house substantially weaken the signal. The antenna always points away from the house, so the power level in the direction of the house is minimal, typically around 1/100 of the level in the forward direction. So the signal in the house will be a tiny fraction of what it is in the direction of the base station. And that is still starting from a transmitter with about the same power output as a cell phone.

Q. Will the transmitters be running all the time?                   [Top of Page]

A. The customer-premise radios will only transmit when they are being actively used by someone in the house, except for some management transmissions. Base stations and backhauls will transmit more of the time when they are heavily used, though they will always be off some fraction of the time.

Q. How are the locations of base stations determined?

A. The design of the network is based on the terrain. Hills totally block the signals and trees severely weaken them. In the rough Appalachian of western New England, sites are selected to shoot across valleys, or to serve an immediate neighborhood. Base station siting is a very painstaking process. [THIS IS FHMS-SPECIFIC] Hawley, for instance, has ridges separating the eastern, middle, and western parts, and the tops of those ridges aren’t accessible. Much of Savoy is in a steep valley along Route 116, so getting signals through there requires very careful pole placement along and above it.

Q. Does the government have standards for radiation safety?

A. Yes. There are very specific limits on exposure set by the FCC, which all wireless providers must meet. And the FCC approval documents for the radios specify the minimum distances they can be from people, which installers must follow. A typical fixed wireless backhaul radio has this restriction: “The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 1m[eter] from all persons”.  A high-powered (3/4 watt) Wi-Fi system has this proviso: “The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 24 cm from all persons”. 

A high-powered cell site needs more isolation. The FCC recently fined T-Mobile when they found beer cans near one of its city rooftop antennas, indicating that it was not properly fenced off.

Q. How much safety margin does a fixed wireless network have compared to what the FCC rules require?

A. If one of the base station antennas is only 40 feet above ground, the signal strength 5 feet above ground will about 1/100,000 of the FCC’s “uncontrolled exposure” limit.  (The “controlled exposure” limit, for people working near the antenna for no more than five minutes, is five times higher.) Even with a few antennas on a pole, that should be a more than adequate safety margin. Higher antennas have that much more margin. Home-mounted antennas should have a similar margin, the specific number depending on where they are mounted. In-home Wi-Fi, from any provider, including DSL, cable, or fiber, has smaller margins.

Q. What is the inverse square law and why does that matter?

A. The inverse square law describes the relationship between distance and received power. It says that the amount of power received is inversely proportional to the square of the distance. So if a transmitter delivers a certain exposure level at a 1 foot distance, then at 10 feet, it’s only 1/100 that level, and at 100 feet, it’s only 1/10,000 that level. That’s why antennas up on a mountain, tower, or pole are usually safe, even if they might have posed a risk if one were very close.

Q. Are cellular phones safe? How do they compare?                   [Top of Page]

A. That is a hard question to answer. A cell phone may use up to 200 milliwatts, and there is some controversy over whether heavy usage at that power level, so close to the head or body, is totally safe. But because of the inverse square law, that same amount of power, at the distances used for a fixed system, become miniscule.

Ironically, a current alternative to a fixed ISP is to use a cellular data device, like a “Mi-Fi”, at least in places where there is adequate cellular service. This type of device is normally omnidirectional, so the power it transmits to the cell tower is not being focused where it is needed. And because it’s indoors, it needs to use higher power to penetrate the walls, while in a fixed wireless system the customer premise radio is outdoors.  So the outdoor fixed system needs less power to begin with and the walls further shield the people inside.

A cellular phone or data device is also safer if it is near a tower, because it automatically reduces its own power to the minimum needed. If it has “four bars”, then it does not use full power. Customer premise fixed wireless radios will also all have automatic transmitter power control, so they too will lower their power even further if the additional power is not necessary to maintain full speed.