Flexible handheld VHF/UHF transceiver antenna

thingiverse

This is handheld UHF/VHF transceiver antenna parts for building single band handheld vertical (rubber duck) antenna for those people who tired of fake mistuned antennas sold on the internet. Base is printed with PETG filament, body/cover is printed with flexible TPU filament. Base is used together with commonly available SMA connector. Was creating spring by wounding 1.3 mm copper wire on 8 mm aluminum tube (see photo). Radiator spring element must be tuned to desired frequency, use calculator in the internet, make spring of proper size, tune with antenna analyzer. When spring with SMA connector is inserted into the base fill with the hot glue, then add body/cover. Built several antennas for 145, 433 and 868 MHz, make sure resonance is in proper place when cover is attached, for 145 MHz must be tuned depending on whether you are planning to use it when holding in your hand or not as human body behaves as counterpoise. Use Smith Chart on your analyzer to see if you need more capacitance or inductance to move resonance to the proper place and whether resistance is close to 50 Ohms. FreeCAD models are included, feel free to modify for your needs.