Discussion on "Thermal-Frequency-Drift Compensation" (by T.R.W. Bushby) [with author's reply]

The design of military communication equipment must consider, among other factors, the effect of varying temperature on the equipment. The commentor feels that Mr. Bushby's article, although very opportune, omits the discussion of a very basic point to his whole article on page 548 where the premise of finding the smallest average drift factor θ over the frequency range is assumed. This criterion is not the most desirable condition. In replying, Mr. Bushby shows that the condition for minimum average drift factor (/θ/) throughout the range can be demonstrated geometrically.