Recently, a reader wrote me asking why there seems to be no standardization when it comes to measuring cell phone signal quality and carrier service in terms of signal quality and reliability. He pointed out that audiophiles get measurements aplenty in terms of signal to noise ratio, db and the like. In contrast, the cell phone specs available to consumers and the press don't offer any help when it comes to reception.
Actually, the industry (both manufacturers and carriers) use -db (decibels) to measure signal strength. So there is standardization. The bad news is that it's rarely easy for a user or member of the press to access the field test mode on every single brand and model of cell phone so that they may see the signal as measured in -db. There are many different ways of getting into field test mode and the manufacturers don't often disclose it (because consumers can also change settings that may render the phone inoperable while in field test).
For example, on the iPhone, enter *3001#12345#* on the keypad and press the call send button. You'll enter field test mode and see the signal in -db in the upper left corner.
On the BlackBerry, press and hold the ALT key and press the N, M, L, L keys while on the home screen to see the bars change to signal in -db. Press that key sequence again to return to the bar view.
These two don't enter a user-editable field test mode so they're safe. Feature phone field test modes often let you muck with arcane settings, which can be dangerous if you don't know what you're doing.
Audiophiles are well-read on the meaning of db and other specs. Average cell phone shoppers aren't though and -db radio signal measurements can be confusing. First off: it helps to revive your high school math lessons: a -69db is better than -99db signal. Remember: negative numbers work the opposite of positive numbers! And it's not the usual 0-100% scale. In general, cell phone signals run from -60db (if you're standing under your carrier's tower) to -120db (where most calls would drop and your phone might not ring).
To make matters more challenging, some phones do much better with a -105db signal than others (-105db is a weak signal). Some will drop calls and have degraded voice while others do well. So even if you did tell you the signal in -db for every phone we reviewed, it's somewhat less important than the phone's perceived performance in terms of call voice quality, noise and drops.
Also, GSM/EDGE and HSDPA (3G) are two different signals being received by 2 separate radio (or radio sections) in your cell phone. So you'll see a different number for one vs. the other. The same goes for CDMA radio technology (used by Sprint and Verizon) where voice and 1xRTT are on separate broadcast channels and radio receivers from EVDO. In fact, many Verizon phones have dual bars to indicate 1x and EVDO. In the world of GSM (AT&T and T-Mobile), both voice and data can run on 3G HSDPA. If your phone is on 3G, the GSM/EDGE signal isn't being used and is irrelevant. On CDMA, voice can not run on 3G EVDO (Evolution Voice Only), so you'll always need the 1x for voice calls.
How about the carriers? (Sprint, Verizon, AT&T, T-Mobile...)
When it comes to what carriers are best in different regions, Consumer Reports and some of the PC magazines do articles from time to time. That's a real challenge though given the nature of PCS/cellular technology. Verizon might be the best in NYC, but they may have a 5 square block dead zone in lower Manhattan so folks who live in that dead zone won't benefit from the knowledge that Verizon is best in NYC. Buildings, hills and valleys obstruct signals, as do other signals, bad weather and NIMBYs (The "not in my back yard" folks) who prevent carriers from erecting towers in their 'hood though they may complain about their crappy cell phone reception. Hilly places like northern California (Silicon Valley and San Francisco) have spotty reception issues because they're very hilly. New York City is a forest of extremely tall buildings with plenty of RF-blocking metal. National Parks have laws that protect the landscape, so there are very few towers. Highways tend to have the best coverage because that's non-residential land so NIMBYs don't get involved and cell coverage is considered a public safety helper on highways.
Why does your mobile phone have crappy reception when you can see a tower from your window? Every carrier has their own towers and panels. Sometimes they share towers but maintain their own panels on that tower (there are many panels on the average cell phone tower). The tower that graces your bedroom window view might not be *your* carrier's tower.
A cell tower mounted on top of a shopping complex. Photo taken with the Nokia N97.
What to do? Ask friends and relatives who use their phones in the same areas you will. Ask them about reception, call quality and dropped calls on their carrier's service. Audition a carrier: they offer 14 or 30 day return policies (depending on your state's laws) so you can test the service and return the phone if it's no good without worrying about an ETF (early termination fee). Just make sure to return the phone and call the carrier to cancel service within the trial period.
-------------------- Lisa Gade Editor in Chief, MobileTechReview
I tried to create interest in a user provided, forum maintained data base of carrier service sites on a different website. That is the best way to know what your service might be like. The carriers' coverage maps are almost useless (VZW is totally useless). I suggest the minimum content for a given cellular service structure would be: Latitude, Longitude, and a list of all carriers at this location. Note that I am using "cellular" generically; some people get upset because they hold that "cellular" should only be used for the 850 MHz band, "PCS" is the 1900 MHz band, etc. Life is too short for this errant pedantry!
My personally gathered data base (incomplete because of paranoid carriers and tower owners)for my tri-state corner of PA, NY, and NJ has more detail but the files are large.
Let me know if this idea can get any traction on MobileTechReview. I'm new here so if I have broken any taboos, let me know that also.