Okay. Now I'm really curious. Shakespeare offers three sizes, 4", 15", 19". They say the bigger the antenna, the greater the range. But antenna size is supposed to be about frequency (says Herr Hertz). So what's up?
Yes, generally frequency is inverse to antenna size, so the higher the frequency, the smaller the antenna needed.
If you're talking about Tacoma KNKX 88.5, then it radiates on the lowest end of the FM scale at 88.5 MHz.
If a person is interested in focusing very specifically on one channel, one can design or "tune" an antenna specifically for that channel.
Wavelength = lightspeed/frequency, so for 88.5, wavelength = 133.4 inches
a 1/4-wave monopole antenna then would be 133.4/4 = 33.35 inches. this is why most car radio rod-type antennas are around 30 inches tall because 1/4-wave monopoles are cheap and effective.
By comparison, the top end of FM radio at 108 MHz, wavelength is 109.3" and a 1/4-wave would be 27.3 inches.
Marine VHF up at 156 correlates to a wave of 75.6 inches so these are not ideal for FM radio.
All that said, likely a practical solution would be just getting a FM or AM/FM monopole somewhere in the ~ 30-inch length range mounted fairly high, then also using good quality low loss coaxial cable from the antenna down to the receiver is also important.