Go to the top of the main page of this Board and clock on the section that says "Wiki," then search for antennas and you'll start learning all the things you need to know. You'll also see that the Wiki section has all kinds of other, useful information, much of it geared to the needs of new users.
Then you can go to the Databases section and look up all the radio frequencies in use in Nassau County.
What town are you in?