All you need is the target frequency and velocity factor for this one. However, if using economy coax, your quoted VC may be off, so if that’s the case, you may want to measure a 90 degree test piece (that’s also shown in the calculations).
To check for accuracy, you can cut a 90 degree section of coax and short out the end. Attach to your analyser and you should get zero SWR at the target frequency. Just a tip.
Here Is the Excel Spreadsheet: phasing harness calcs
Here’s a really simple way of double checking how to much to trim your antenna elements.
You only need to type in the numbers in the Cyan boxes.
- For Dipoles: Cut / Add the result to each leg
- For Verticals: Cut / Add result to your vertical radiator
Just type in where it is resonant right now – then type in where you would like it to be resonant and the spreadsheet will auto-calculate the trimming.
* Thank you to Aubrey (AubsUK on YouTube) for the Online version below: