To calculate the half wave length of the matching section of the 4:1 coax balun for matching 50 ohms to 200 ohms.
Equations are taken from the ARRL Antenna Book. Original page at http://n-lemma.com/calcs/dipole/balun.htm

Input Values

Change the value, move the cursor to empty space and click there
to re-calculate.
Frequency (MHz) =
Velocity Factor (decimal percent e.g 0.84) =
If you are not sure of the VF check on the form on the technical data page.
Westflex 103 is 0.81 and Quickform 141 is 0.7

Output Values
Click in any of these boxes to calculate

Half Lambda Coax Matching Section Length (Ft.) =
Half Lambda Coax Matching Section Length (Ins) =
Half Lambda Coax Matching Section Length (cm) =