Arrow Antenna Dual Band J-Pole (2 meter & 70 cm) Review - YouTube
Figure I from Design and analysis of dualband J-Pole antenna with variation in “T” shape for transceiver radio communication at VHF and UHF band | Semantic Scholar
antenna theory - How do dual band J poles work? - Amateur Radio Stack Exchange
Ed Fong J-Pole Antennas - Dual Band, 220 and Roll-up – Ham Radio 2.0