Cell Tower and Cell Site Location Data: A Primer
In reviewing some online commentary about cell tower location data on various forums and websites purporting to offer free cell tower location data, I thought it might be helpful to explain what is available and what is not available to individuals looking for cell tower and cell site locations.
CELL SITE VS CELL TOWER
Many people make the mistake of comparing “cell sites” and “cell towers”. I regularly receive inquiries from people who say they have a “cell tower” on their roof. What they actually mean to say with rare exception is that they have a “cell site” or cellular antenna site on their rooftop. A “cell site” is simply the antenna installation. A “cell tower” is the support structure upon which a single or multiple “cell sites” are installed. “Cell sites” can also be installed on rooftops, water towers, billboards, signs, hillsides, ect. (In rare cases, there are cell towers installed on top of rooftops.)
CELL SITE VS CELL TOWER
Many people make the mistake of comparing “cell sites” and “cell towers”. I regularly receive inquiries from people who say they have a “cell tower” on their roof. What they actually mean to say with rare exception is that they have a “cell site” or cellular antenna site on their rooftop. A “cell site” is simply the antenna installation. A “cell tower” is the support structure upon which a single or multiple “cell sites” are installed. “Cell sites” can also be installed on rooftops, water towers, billboards, signs, hillsides, ect. (In rare cases, there are cell towers installed on top of rooftops.)
In the industry, we divide cell sites into three categories:
1. Rawland: A proposed site for a new tower which will accommodate multiple “cell sites” or “collocations”.
1. Rawland: A proposed site for a new tower which will accommodate multiple “cell sites” or “collocations”.
2. Collocations: The installation of a single carrier’s equipment and antennae on an existing tower.
3. Tenant Improvements: The improvement of an existing structure other than a tower. This can be a water tower, a building rooftop installation, or any other non-tower structure.
It is difficult to estimate the number of cell sites in existence. In a few previous posts, we have indicated the number of cell towers owned by the top 20 towers companies (as ranked by RCR who does a yearly informal and somewhat inaccurate poll), our article on estimates of the total number of cell sites owned by each carrier, and estimates of the number of towers owned by each wireless carrier.
COMPLETENESS OF TOWER DATA
To start with, there are no comprehensive tower databases that I am aware of, including Steel in the Air’s. We are contacted on a weekly basis by individuals looking to procure “cell tower” data. However, most of these people are actually looking for “cell site” data. They don’t need to know where towers are but instead want to know where each carrier has their sites. There are multiple reasons why they want to know:
1. Location Based Services (LBS): The wireless carriers are required by the FCC to be able to Enhanced 911 (e911) services for wireless devices which enables emergency providers to locate cellular handsets with a moderate degree of accuracy. Many entrepreneurs desire to use “cell site” locations and coordinates to establish locations for their wireless service. From the location of an individual cellular provider’s cell towers and cell sites, these entrepreneurs intend to triangulate their service’s user’s locations. Unfortunately, we are not aware of any commercially available service whereby this data can be purchased or is otherwise available except through from each individual carrier.
3. Tenant Improvements: The improvement of an existing structure other than a tower. This can be a water tower, a building rooftop installation, or any other non-tower structure.
It is difficult to estimate the number of cell sites in existence. In a few previous posts, we have indicated the number of cell towers owned by the top 20 towers companies (as ranked by RCR who does a yearly informal and somewhat inaccurate poll), our article on estimates of the total number of cell sites owned by each carrier, and estimates of the number of towers owned by each wireless carrier.
COMPLETENESS OF TOWER DATA
To start with, there are no comprehensive tower databases that I am aware of, including Steel in the Air’s. We are contacted on a weekly basis by individuals looking to procure “cell tower” data. However, most of these people are actually looking for “cell site” data. They don’t need to know where towers are but instead want to know where each carrier has their sites. There are multiple reasons why they want to know:
1. Location Based Services (LBS): The wireless carriers are required by the FCC to be able to Enhanced 911 (e911) services for wireless devices which enables emergency providers to locate cellular handsets with a moderate degree of accuracy. Many entrepreneurs desire to use “cell site” locations and coordinates to establish locations for their wireless service. From the location of an individual cellular provider’s cell towers and cell sites, these entrepreneurs intend to triangulate their service’s user’s locations. Unfortunately, we are not aware of any commercially available service whereby this data can be purchased or is otherwise available except through from each individual carrier.
2. Comparison of Coverage: End users often want to know how strong the signal from a respective tower is in a given area. The carrier’s online coverage maps in some cases show strength of service to varying degrees but they rarely show specific locations for towers. And for those carriers that do show tower locations, they always only show those towers that they own that are available for collocation. In other words, they don’t show every “cell site”. In most cases, the towers shown only represent 20% or less of their complete network “cell sites”. Alternatively, some individuals with cell tower ground leases are looking to see whether a recent threat to renegotiate their AT&T/Cingular cell tower lease or Sprint/Nextel cell tower lease are predicated by the existance of other cell sites in the vicinity.
3. Competitive Cell Tower Location Data: Many of our clients are actually tower companies who need a competitive advantage in knowing what towers are in an area that they intend to either acquire or build a tower. While many smaller local tower companies can simply send someone to drive the area, when you are dealing with the acquisition of 500 towers, it is not feasible. To that end, we have consolidated 65,000 actual tower locations from numerous tower companies, wireless carriers, and government sources. Combined with the FCC data, that represents 125,000 actual towers. Some of these are publicly available, some are not. And unlike our competitors who provide listing services for anyone with a piece of property who wants a tower on it, when we suggest that a tower exists at a particular location, you are very unlikely to find a vacant piece of land that some realtor listed to get a cell tower lease.
4. Backhaul Alternatives: We are regularly contacted by entities that either own optical fiber rings or ones that are considering purchasing dark fiber to compare the location of fiber to the presence of cell towers and cell sites. These entities wish to determine where they can augment their income to provide backhaul services to wireless sites.
PUBLICLY AVAILABLE DATA
Many of the available online sources of tower data simply regurgitate the records available from the FCC. Please note that there is no requirement by the FCC or any other government agency to register individual “cell sites”. Cellular service is licensed by the region, meaning that the FCC grants the wireless carriers a general license for a county or other geographic region. As long as they conform to the frequency and power limitations of these licenses, they can build anywhere (with local zoning approval).
There are numerous types of data available from the FCC for antenna sites. However, these online sources do not distinguish between what the datasets provide. This appears to create a good deal of confusion between users. Below are some of the datasets provided by the FCC.
1. Antenna Structure Registrations. (ASR) Many of the free online sites for tower data use this as the base data. (Antenna Search.com, Cell Reception.com) Antenna Structure Registration is required by the FCC for those tower sites that pose a threat to air safety. In short, this means towers that are over 200’ tall or those towers that are within 5 miles of an airport. Accordingly, if a tower is under 200’ and is not within 5 miles of an airport, it does not have to be registered with the FCC. (For a indication of how many towers exceed 200' tall- see our previous post on cell tower heights.) It is important to note that ASRs are only necessary for towers- not cell sites. Oftentimes, the owner of the antenna structure or “cell tower” is not the wireless carrier, it is a tower company who built the tower or a tower aggregator like American Tower or Crown Castle who purchased the tower sites from the wireless carriers. To complicate matters, many of the FCC ASRs are not actually used for cellular communications. They can be two way radio towers or broadcast towers or other wireless internet service towers. There are approximately 110,000 antenna structure registrations.
PUBLICLY AVAILABLE DATA
Many of the available online sources of tower data simply regurgitate the records available from the FCC. Please note that there is no requirement by the FCC or any other government agency to register individual “cell sites”. Cellular service is licensed by the region, meaning that the FCC grants the wireless carriers a general license for a county or other geographic region. As long as they conform to the frequency and power limitations of these licenses, they can build anywhere (with local zoning approval).
There are numerous types of data available from the FCC for antenna sites. However, these online sources do not distinguish between what the datasets provide. This appears to create a good deal of confusion between users. Below are some of the datasets provided by the FCC.
1. Antenna Structure Registrations. (ASR) Many of the free online sites for tower data use this as the base data. (Antenna Search.com, Cell Reception.com) Antenna Structure Registration is required by the FCC for those tower sites that pose a threat to air safety. In short, this means towers that are over 200’ tall or those towers that are within 5 miles of an airport. Accordingly, if a tower is under 200’ and is not within 5 miles of an airport, it does not have to be registered with the FCC. (For a indication of how many towers exceed 200' tall- see our previous post on cell tower heights.) It is important to note that ASRs are only necessary for towers- not cell sites. Oftentimes, the owner of the antenna structure or “cell tower” is not the wireless carrier, it is a tower company who built the tower or a tower aggregator like American Tower or Crown Castle who purchased the tower sites from the wireless carriers. To complicate matters, many of the FCC ASRs are not actually used for cellular communications. They can be two way radio towers or broadcast towers or other wireless internet service towers. There are approximately 110,000 antenna structure registrations.
2. Specific Frequency Licensed Locations. The FCC does require some wireless services to register individual locations. There are numerous databases available from the FCC on different wireless service types. For instance, most microwave installations require specific site registrations. Paging and mobile radio installations do as well. Some of the online services purporting to provide data about cell towers actually use the frequency databases. Unfortunately, these locations rarely equate to cellular towers or “cell sites”. So someone viewing these databases will end up paying for what they presume to be cell tower data and in reality they are paying for paging locations or two-way radio locations. (or even Ham Radio).
In essence, if you use the free services that regurgitate the FCC data, recognize that you are getting what you paid for. I personally would not waste my money on any service that offers to sell you the FCC data. (It is available for free from other online sites and can be downloaded from the FCC website for free, although the translation of the database is not simple.)
In essence, if you use the free services that regurgitate the FCC data, recognize that you are getting what you paid for. I personally would not waste my money on any service that offers to sell you the FCC data. (It is available for free from other online sites and can be downloaded from the FCC website for free, although the translation of the database is not simple.)
STEEL IN THE AIR DATA
We have assembled a comprehensive database of tower and cell site locations from numerous sources, including the public FCC data, FAA data, and tower companies that provide their data online. We also have represented over 1000 clients with cell site leases for a few thousand cell sites. For many of those clients, they helped fill in missing data in their area by driving around. In addition, we have independently gathered specific cell site from various sources including paying people to literally drive areas of interest and visually identify towers. Some of our data includes lease rate data, most of it doesn’t. We use our data to assist our clients with determining where cell sites are. In a number of cases, we don’t have complete cell site data for an area. However, we know how to “fill in the holes” and how to assess areas for existing cell sites. In short, we make it our business to collect cell tower and cell site data and create tower location maps. We don’t simply regurgitate free government data.
We have assembled a comprehensive database of tower and cell site locations from numerous sources, including the public FCC data, FAA data, and tower companies that provide their data online. We also have represented over 1000 clients with cell site leases for a few thousand cell sites. For many of those clients, they helped fill in missing data in their area by driving around. In addition, we have independently gathered specific cell site from various sources including paying people to literally drive areas of interest and visually identify towers. Some of our data includes lease rate data, most of it doesn’t. We use our data to assist our clients with determining where cell sites are. In a number of cases, we don’t have complete cell site data for an area. However, we know how to “fill in the holes” and how to assess areas for existing cell sites. In short, we make it our business to collect cell tower and cell site data and create tower location maps. We don’t simply regurgitate free government data.
Labels: cell sites, cell tower locations, cell towers, Rooftop cell sites, tower maps
posted by Steel in the Air @ 3:11 PM
4 Comments:
Another source of cell site info is being accumulated by Navizon by leveraging users with GPS in their phones. Navizon is accumulating data on both cell sites and WiFi signals. I haven't used their service but I did create a free account on their site and browse their Google maps mashup in the area near my home. Very interesting. I blogged about it here:
http://blogs.nmss.com/communications/2007/09/navizon-is-buil.html
To be fair, the content at Navizon's website does not show the locations of actual cell sites- it just shows signal strengths at various locations entered by users or their phones. Perhaps Navizon is putting together cell site data- but it does not appear that they are sharing it. If this is incorrect- please feel free to post another comment.
It appears that Google is beating Navizon to the punch and bringing their large user base to bear on this problem.
Google's "My Location" feature pinpoints (within 1500 meters) a user's location based upon the cell ID on the user's phone. I tested this feature the other day and it appears that it works as promised.
Google already has a sizeable database of general locations of cell tower sites by cell ID. However the application does not tell you where Google Maps believes the tower location is.
Rather than triangulating the signal, Google Maps just attaches your location to where it believes the tower and suggests that you are withing 1500 meters of the site. Its a fairly accurate process- my test showed where I was withing 500ft.
I assume that Google will not be sharing the cell site location data- no need to inflame their relationship with the wireless carriers whom represent a large opportunity to expand their search ads to mobile devices.
The interesting thing is, assuming the application software on the handset has access to signal strength as well as cell ID, then you can do Trilateration http://en.wikipedia.org/wiki/Trilateration on multiple cell sites.
Of course, positional accuracy will be better with smaller cells at higher density. So, Navizon (also Skyhook Wireless) capture both mobile cell site data and WiFi signals. The WiFi signals are much denser so, using them, their accuracy goes way up.
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