There are all kinds of programs and software to search for frequencies. Back in the late 1980s, I even wrote a program in BASIC for an Apple IIC to do FM Frequency Searches. It worked, but not very well. I finally decided that my time was better spent buying software than writing it, so I bought some. I would have spent all my time trying to update my database. I did all kinds of things, went to the FCC field offices, called stations, called the FCC, interpolated USGS Topological Maps, etc. I did use an engineering study made with my program to support a Petition For Rule Making, and an FM frequency was dropped into the Table of Allotments as a result. Since the FCC now requires a hefty fee to just drop in a frequency, I no longer do it. I also did allotment studies of this type, but I could never convince many clients to pay enough to make it worthwhile. I was the consultant of last resort. I did some clever drop ins, upgrades, and even a few approved CP applications, if I do say so myself, but the proportionate amount of money just wasn't there. Sometimes, clients would take advantage of me. Clients with a lot of money hired the big consulting engineers anyway. I had long ago decided to take my father's advice (my father had worked in radio in the 1920s and 1930s), and found a better career. I am still interested in radio obviously.