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BELL SYSTEM TECHNICAL JOURNAL 



permit a ±3.6 per cent frequency range. Several designs of 3 kmc echo 

 boxes have been based on this area. 



Fig. 6 — Design chart for cylindrical cavity resonators operating in the TE Gin modes. 



Fig. 7 — Exjianded mode chart covering the operating area of a 9 kmc echo box. 



This type of solution is quite adequate for many of the simpler designs; 

 but as the required Q becomes larger or the frequency coverage becomes 



