Here are the plan I use for constructing and experimenting with Slim Jim antenna on 2 Meter VHF Amateur band. The measurement used are designed to center around 144-148 MHz radio frequency, which is used by amateur radio world wide.
FYI this is the plan that I use to construct my first ham radio antenna using PVC pipe and aluminium tube.
Credit to Pak Halim and Azmeer for giving this plan and showing me how to construct a proper antenna.
2 Meter Slim Jim using 300 Ohm tv cable (Ribbon Antenna)
Here’s the plan that I use for constructing Slim Jim antenna for portable radio (ICOM V8).
Both design are meant to be fed with 50-Ohm impedance coax feed line (RG-58/RG-8/RG-213) to obtain the most optimized results