If you try to make an antenna too small compared to wavelength, it will become less efficient and more difficult to design. 900 MHz is the 33 cm band, so if you

If you try to make an antenna too small compared to wavelength, it will become less efficient and more difficult to design. 900 MHz is the 33 cm band, so if you have a more standard size antenna on the order of quarter-wavelength size, you get an antenna that’s about 8cm.