The primary purpose of the helix in a travelling-wave tube is to:

1.	The primary purpose of the helix in a travelling-wave tube is to:
A.	Prevent the electron beam from spreading in the long tube
B.	Reduce the axial velocity of the RF field
C.	Ensure broadband operation
D.	Reduce the noise figure
Answer» C. Ensure broadband operation

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The primary purpose of the helix in a travelling-wave tube is to:

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