The effective recombination coefficient &psgr; (z) is determined at 2020 UT on November 2 (day) and at 0605 UT on November 3 (night) during the November 1969 solar particle event (SPE). Electron and proton spectrum and electron density measurements were all made aboard the same rockets launched at these times from Fort Churchill. These measurements provide the basis for an accurate &psgr; (z) profile determination up to 90 km for these two specific times. The results are compared directly with those of other workers, and the experimentally observed variation of &psgr; (z) with ionization rate at night is compared with theoretical predictions.