850 or 1900 MHz??

This can be confusing. Verizon operates their EVDO network in two different frequencies. 850 MHz (sometimes referred to as 800) or 1900 MHz. If you don't know which one they are using in your area that creates a problem. Say you want to buy an external antenna, if its not tuned to the correct frequency ... it won't work.

You can call Verizon technical support and maybe you'll get a knowledgeable person who knows exactly what it is. More often than not you will receive a clueless answer.

Here's how to determine it for yourself.

Open up the options menu (press CTRL-D and enter the password diagvzw), click on "Field Test" (you may have to be disconnected from the internet) ... and look at the channel number:

(Alltel users -disconnect first, then place cursor on Qlinkmobile - press CTRL-D enter password diagsmsi )

(some versions of VZAccess have the frequency clearly labeled in this menu)

Now compare that number to this frequency chart:

click to enlarge

800 MHz chart here
1900 MHz chart here

In the example given you see that 630 falls in the B channel between 356 and 644 and is not evenly divisible by 25. Therefore this modem is operating on the 850 MHz frequency.
A good rule of thumb: If the channel number cannot be evenly divisible by 25 - you are 800 MHz

With Sprint, all of it is 1900 MHz so there is no question.
There is a nationwide map that shows 850 MHz only (no PCS/1900 MHZ). Go here and select your region.

Factoid: It takes twice as many cell towers to cover the same area with 1900 MHz as it does with 850 MHz ... how many Verizon towers that are nearby may offer a clue to frequency used. For example, in my area it takes five Sprint towers to cover the same area as Verizon does with only two. Using a Verizon cellphone and checking its field test menu will probably tell you as well. wpsantennas.com has a PDF of phone codes here.