1. INTRODUCTION

2. FOURIER TRANSFORM OF 21 CM DATA

3. ASSESSING $f_{\mathrm{low}}^{0.12}$ USING A NUMERICAL SIMULATION

4. ASSESSING $f_{\mathrm{low}}^{0.12}$ WITH POINTED OBSERVATIONS

6. APPLICATION TO MAPPED 21 CM DATA FOR DHIGLS DF

9. DISCUSSION

10. SUMMARY