Frequency instability of pulsed transmitters with long wave guides

The possible steady frequencies at which a pulsed magnetron can oscillate when loaded with a long mismatched feeder are considered, and the stability of frequency is examined. In addition there is a discussion of the transient state, peculiar to the feeder system, which occurs before the steady frequency is reached. It is shown that two types of frequency instability may exist; in the first type the frequency may change from pulse to pulse, in the second type it may change during the pulse. A similar adjustment will remove both types of instability, but elimination of the second type is considerably more critical than that of the first. The first type causes a reduction in the tuning range available from a tunable magnetron. The second type does not occur until the length of feeder becomes great enough for the time of transit of energy along it to be significant.