SBA COMMUNICATIONS CORPORATION Exhibit 12.1 RATIO OF EARNINGS TO FIXED CHARGES COMPUTATIONS Year ended Year ended Year ended Year ended Year ended 12/31/93 12/31/94 12/31/95 12/31/96 12/31/97 ----------------------------------------------------------------------- Earnings: Income (loss) before taxes 83 1,846 3,298 2,366 6,798 Plus: fixed charges 23 45 101 495 876 ----------------------------------------------------------------------- Total Earnings 106 1,891 3,399 2,861 7,674 Fixed Charges: Interest Expense 9 19 11 139 407 Preferred Dividends 0 0 0 0 983 Interest Component of Operating leases 14 26 90 356 469 ----------------------------------------------------------------------- Total Fixed Charges 23 45 101 495 1,859 Ratio 4.6x 41.82x 33.8x 5.8x 4.1x Three months Three months ended ended 3/31/97 3/31/98 ------------------------------ Earnings: Income (loss) before taxes 2,310 (1,372) Plus: fixed charges 153 1,997 ------------------------------ Total Earnings 2,463 625 Fixed Charges: Interest Expense 36 1,880 Preferred Dividends 83 438 Interest Component of Operating leases 117 117 ------------------------------ Total Fixed Charges 236 2,435 Ratio 10.4x .3x SBA COMMUNICATIONS CORPORATION PRO FORMA RATIO OF EARNINGS TO FIXED CHARGES COMPUTATIONS THREE YEAR ENDED MONTHS 12/31/97 03/31/98 --------------- -------------- Earnings: Income (loss) before taxes (11,965) (4,971) Plus: fixed charges 19,759 5,096 --------------- -------------- Total Earnings 7,794 125 Fixed Charges: Interest Expense 19,290 4,979 Preferred Dividends 983 438 Interest Component of Operating leases 469 117 --------------- -------------- Total Fixed Charges 20,742 5,534 Ratio .4x .1x Page 1