In fact, the antenna of the walkie talkie is not distinguished by the length of the antenna, but by the frequency band. Although the antenna is usually selected with long or short antennas, the final selection is based on the frequency written by the walkie talkie. You can look at the bottom of the antenna. Generally, there will be remarks at the bottom of the antenna to explain the applicable frequency range of the antenna. If the frequency written by the walkie talkie is within this range, the antenna is applicable. Of course, each interphone manufacturer produces each interphone with a central frequency.