We measure the redshift-space power spectrum P ( k ) for the recently completed IRAS Point Source Catalogue ( PSC ) redshift survey , which contains 14500 galaxies over 84 \% of the sky with 60 micron flux \geq 0.6 Jansky .
Comparison with simulations shows that our estimated errors on P ( k ) are realistic , and that systematic errors due to the finite survey volume are small for wavenumbers k \lower 2.15 pt \hbox { $ \buildrel > \over { \sim } $ } 0.03 h { Mpc } ^ { -1 } .
At large scales our power spectrum is intermediate between those of the earlier QDOT and 1.2 Jansky surveys , but with considerably smaller error bars ; it falls slightly more steeply to smaller scales .
We have fitted families of CDM-like models using the Peacock-Dodds formula for non-linear evolution ; the results are somewhat sensitive to the assumed small-scale velocity dispersion \sigma _ { V } .
Assuming a realistic \sigma _ { V } \approx 300 { km s ^ { -1 } } yields a shape parameter \Gamma \sim 0.25 and normalisation b \sigma _ { 8 } \sim 0.75 ; if \sigma _ { V } is as high as 600 { km s ^ { -1 } } then \Gamma = 0.5 is only marginally excluded .
There is little evidence for any ‘ preferred scale ’ in the power spectrum or non-Gaussian behaviour in the distribution of large-scale power .