Wireless service after Sandy -- what you need to know (FAQ)

Hurricane Sandy has affected millions of people up and down the East Coast. Now the storm, which was downgraded just before landfall Monday night in New Jersey, has moved westward to wreak further havoc on communications networks in its path.

Because I have been getting so many questions from friends, family and readers about what is going on with the wireless networks in these areas, I put together this Frequently Asked Questions or FAQ for my Ask Maggie readers. If you have additional questions, please send them my way, and I will try to answer them. Also, if you want more information on these outages, look for my news stories which will have the latest updates.

I live in Manhattan. And I can't get cell phone service in some places, but if go a block or two away I can get service. Some people with a different carrier can get better service than I can. Also, I know that people uptown have not had any service disruption. Can you please explain why this might be happening?

First, let me preface this by saying that I don't know the specifics of any particular carrier's network outages in New York City or elsewhere, because the companies haven't released those details. What I do know is that the FCC said that on average 25 percent of cell sites in 10 states where the hurricane hit, were not functioning as of 10 a.m. ET Tuesday morning.

The spotty service that many in New York City and elsewhere are experiencing is likely a result of these cell sites being knocked out of service. To understand why service is bad in some places but gets better a few blocks or even a few miles away, you have to understand at a basic level how these networks are built and how they operate.

Wireless networks are often called "cellular" networks because they are built by knitting together thousands of "cell sites." In other words, a radio will transmit signals 360 degrees out to a certain radius. And within that cell of coverage it will service a certain number of customers. When people move out of one cell, they will enter another cell and that's how the service is able to follow them as they're mobile. Wireless operators do calculations to assess how many customers they expect to service in a single cell at any one time. And they also calculate how much capacity they need to service all those customers.

In a city like New York, a carrier has to deploy a lot more cell sites to cover the millions of people coming and going each day. Cell sites in New York City tend to be smaller than say in a rural area, such as Wyoming. The reason is there are many more customers to serve per square mile than there are in a rural area like Wyoming.

If a cell site goes down, then customers in that area may not receive any service. And in rural areas where there are fewer cell sites, that's more likely. But in places like New York City, where there are hundreds of cell sites in relatively close proximity, users may be able pick up signals from adjacent cell sites. This is likely why people won't have service on one city block, but they will if they move in one direction or another.

But when adjacent cell sites pick up traffic from a cell site that is no longer in the network, it means that those surrounding cell sites are now handling additional customers and additional traffic. Since the cell sites are only able to handle a certain amount of usage, when they become overloaded with additional users, they don't function optimally. What this means for consumers is dropped calls or you won't be able to make calls at all.

This is likely what's been happening in lower New York City and other places where cell service is spotty after the storm. But there may be other issues as well. For example, the cell sites themselves may not be damaged, but the switching centers or the infrastructure that carries the traffic from those cell sites to the carriers' core networks may be damaged, as well, which could also disrupt service.

I thought the cell sites had weather-proof radios and back-up power supplies. Why are there still outages?

The two biggest issues for a cell site during a storm like Hurricane Sandy are its power supply and making sure the equipment itself isn't damaged by wind, rain, flood or snow. Cell sites require power to keep the radio transmitting signals. Without power, cell sites can no longer function. You are correct about the back-up power supplies. Carriers keep back-up generators and batteries at these cell towers to make sure they are still running when the commercial power is out. Sprint says it has enough power at its back-up sites to last for 48 to 72 hours.

But sometimes this back-up power may fail. Or in the case of this storm there is a chance that flooding may have damaged the power supplies at some sites. Also once those batteries or generators go out, commercial service needs to kick back in or they need to be replaced, recharged or refueled.

As for the radio equipment itself, you are also right about the fact that it is hardened for harsh outdoor weather conditions. But 80 to 90 miles per hour wind gusts are strong and can do damage. Also flooding from tidal surges, rain water, as well as, snow and ice can also damage equipment. And let's not forget about flying debris or trees that fall onto transmission towers that may also cause damage during a storm.

Wireless companies can often repair damaged equipment, or they can replace or recharge batteries. But they can only do so once it's safe for technicians to get to affected areas. And they can even bring in temporary and portable towers ready to be deployed to fill in until repairs can be made. These cell-on wheels, or COWS, can be rolled into communities or areas where cell service is disrupted. But they can only do so once it's safe for workers to go into those areas. In the case of Hurricane Sandy, which was spread across such a large region, that might take days or in some cases weeks.

If a cell site goes out, does that mean I won't get any service? And if my carrier's service is disrupted could I be able to pick up service from another carrier?

As I explained above, the answer is "maybe." Depending on where you are and depending on the strength of signals coming from adjacent cell sites, you may be able pick up a signal from another cell site. But unless your wireless provider already has a roaming agreement with another provider, you will not be able to pick up service from another carrier.

If I live in an area affected by Hurricane Sandy and I have wireless service now does that mean I am in the clear?

Not necessarily. The FCC said that 25 percent of cell sites are reported to be completely out. But the agency also said there were many cell sites currently operating on back-up batteries and generators. This means that once the batteries run or the fuel runs out on the generators, those cell sites will no longer function. So if you live in an area where commercial power has not been fully restored, there's a chance that your cellular service could degrade.

That said, even if power remains out, if workers can get to those cell sites and refuel them or replace the batteries, then cell service should continue to work. Still, the FCC said they expect wireless service to get worse before it gets better. So stay tuned.

Also be aware that the FCC is advising all wireless subscribers in areas affected by Hurricane Sandy to restrict long phone calls so that people in areas where capacity is limited can get through in case of an emergency. Instead, the FCC chairman advises people to use social media to let loved ones know you are ok. Text message friends, family and coworkers instead of calling. This will also conserve the valuable and possibly limited wireless capacity on the network.

How quickly can I expect cell phone service in my area to be restored?

The speed with which service is restored depends on several factors. If it's too dangerous for crews to get to the areas where they need to be to replace power supplies or to repair damaged equipment, then it could take some time before service is fully restored. The four biggest wireless providers say they are working quickly to restore service. But service recovery will largely be carrier specific.

T-Mobile issued a statement Tuesday evening stating that in Washington, D.C., the network is more than 90 percent operational. In New York City, the network is more than 80 percent operational. But the carrier also noted that "restoration work continues in the harder hit areas of lower Manhattan, Staten Island, Long Island, coastal and Northern New Jersey, Connecticut and portions of Pennsylvania, including Philadelphia."

Verizon Wireless said Tuesday afternoon that even in the hardest hit areas in the Northeast that 94 percent of its cell sites are up and running. And the carrier said that all of its switching and data centers are functioning normally.

The company also noted in its statement that the "the majority of the problems are 'out of service' sites resulting from multiple factors, including telco service disruption, power outages and flooding in low lying areas such as the tip of lower Manhattan."

Will cell phone service be fully restored as long as we don't have power in my area?

As I stated above, power is key for these cell sites to remain up. And without commercial power, it will be very difficult for wireless operators to fully restore service. That said, they may be able to refuel sites that have generators or they may be able to replace batteries. But if your area doesn't have any commercial power for a long stretch of time, it's very likely that you will also suffer from poor cell phone coverage since it will difficult for the carrier to maintain maximum cell site coverage.

If I currently don't have power in my home, what's the best way to conserve my battery on my cell phone?

My colleague Roger Cheng prepared a quick guide that will describe how best to conserve your cell phone's battery. I'll summarize the relevant options for you here:

• Turn off the extra wireless connections, such as Bluetooth, Wi-Fi, 4G and GPS satellite radio.
• Limit your usage.
• Share phones with others you live with.
• Use airplane mode to turn all your radios on and off. This way you can check back in periodically without powering down your device.
• Turn off push notifications you get from social media sites and email.
• Close unnecessary apps.
• Do not stream video or audio.
• Dim the display.
• Send text messages instead of calling.
• Recharge your phone by using your car charger, if you have a car and you have a charging adapter.

I hope this helped explain some of the questions that many readers have had about why you may be experiencing some service disruption. If you have additional questions, please send me an email.

Ask Maggie is an advice column that answers readers' wireless and broadband questions. The column now appears twice a week on CNET offering readers a double dosage of Ask Maggie's advice. If you have a question, I'd love to hear from you. Please send me an e-mail at maggie dot reardon at cbs dot com. And please put "Ask Maggie" in the subject header. You can also follow me on Facebook on my Ask Maggie page.