A friend was looking at material on the SR.177 and noted that it said it was to have A.I.23 with an 18″ reflector, and he began looking to see if this was the same as on Lightning or different.

All he could find mentioned the proposal for a modified Lightning with a reflector of 27″… and on a thread on the Secret Projects board a poster claimed the production Lightnings had a 24″ reflector.

This seemed a bit large to him, and thus the question.

As a general rule, the larger the reflector diameter, the longer the range of the set, and the better the sensitivity becomes.

Thus, if the SR.177 had a smaller reflector, it would not have been as capable of conducting a radar-guided intercept as the Lightning.