Palstar ZM-30, Operating Manual, Page: 11 / 15

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references such as the ARRL Antenna Book. If you cannot find the value or if you are using a custom type of
feedline, the section in this manual titled “Velocity Factor Measurement” provides a way to determine this value.
The following formulas can be used to estimate the length of transmission line required.
For a half-wavelength stub the length is:
Where L is the length in inches, VF is the velocity factor and F is the operating frequency in MHz for the stub.
Similarly for a quarter-wave stub use the formula:
7.0 Technical Support
If you experience any problems with the ZM-30, or if you have any questions relative to its operation or
specifications, please contact Palstar at (937) 773-6255. Be sure to visit the ZM-30 product website at
www.palstar.com to check for product updates and other technical information
.
L = 5904 * VF
F
L = 2952 * VF
F
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Figure 3