Rule of thumb is:What are the optimum antenna lengths for cell phones?Cheers Phil
234 divided by the frequency in MHz. This gets you close to a 1/4 wave antenna length for most frequencies.
234/27.185 MHz = 8.6 feet for CB Channel 19
234/52.525 MHz = 4.45 feet for the 6 meter Ham band
234/147 MHz = 1.59 feet for the 2 meter Ham band
234/860 MHz = .27 feet or 3.24 inches for the 800 MHz Cell band.