Measurements of solar radiation in the vicinity of the Al i absorption edge at 2075 ¿ provide a means of comparing the magnitude of the 11-year variation in solar activity with that of the 27-day variation. The ratio of the solar irradiance in the band 2030-2070 ¿ has been determined from five measurements made in the period 1977-1983. This ratio, is an almost purely relative measurement, avoids the problem of absolute irradiance comparisons over long periods of time. The magnitude of the 11-year effect in this ratio is about ¿1%, which is comparable to that in the 27-day effect measured at solar maximum.