Please note that an antenna doesn't know, nor does it care, what TYPE of signal it is, only what frequency it is. That said, polarization also matters. If an antenna is designed to work in the 800 MHz range (and in our case is vertically polarized) then it should work well on an 800 MHz signal. This is regardless if that signal is for a cell phone, trunked radio system, conventional radio channel, television broadcast signal (although those are horizontally polarized), telemetry from remote sensors, analog, digital, pulse, whatever.
OK, those antennas are MARKETED as cell phone antennas. So what. They have the correct polarization (vertical). They're designed for the correct frequency range (800 MHz). They should work just fine. All yagi antennas are NOT cell phone antennas. They're directional vertical antennas that happen to work on the frequency range some cell phone frequencies operate (along with many other services). The folks that sell those antennas BELIEVE that the cell phone market WILL BUY them so they MARKET them to those folks.
As a directional antenna, it is important that it be aimed correctly at the tower. Depending on the design of your particular antenna, pointed correctly it should work just fine, but if you're off by more than just a few degrees, it may not work well at all. If you're attempting to use a yagi on a simulcast system, it's important to isolate an individual tower since you're not really trying to get a super strong signal, but eliminate the signals from other towers. Depending on your specific situation, you may need to point at a further away tower that has no other towers along that same line than point to the closest tower that has another tower further away in the same direction as your closest one.
They may price them differently dependent on how they market them as well. If you remember back that far, they used to market TV antennas as "Color TV Antenna" and asked a higher price than the old "TV Antenna" that didn't say color. Not too long ago, the same thing happened when they marketed TV antennas as "HD Ready" when in reality it was the same antenna they used to sell as a run-of-the-mill "TV Antenna". That "HD Ready" sticker was EXPENSIVE since it nearly doubled the price of the same antenna without that special "HD Ready" sticker on the box.
