Bests & Worsts Reviews from Amazon

Just got this antenna today and immediately tested it with a freshly calibrated Vector Network Analyzer. The VSWR is 4.0 at 144 MHz and 3.0 at 148 MHz. The resonant frequency is ~165 MHz. For 70 cm, the numbers look a little better: VSWR = 3.7 @ 420MHz and VSWR = 1.6 @ 450 MHz. What do these numbers mean? VSWR measures the amount of power that if reflected back from the antenna to the transmitter due to impedance mismatch. VSWR = 1 means that there is no impedance mismatch and that all power is transferred to the antenna. When VSWR reaches 2, about 11% of power is reflected back to the transmitter -- enough for some radios to start reducing output power in order to prevent damage. VSWR of 4, as seen in this antenna at 144 MHz, corresponds to 36% power reflection. This is simply bad and totally unacceptable for a $30+ whip. The stock 7" antenna on my handheld which I was hoping to upgrade had a VSWR of about 2.0 at 144 MHz. I will contact the manufacturer with my findings. The antenna will likely be going back to Amazon. ------------------------------------------------------------------------------- UPDATE: I contacted the Japanese office of Antenna Diamond, and after a week of silence and a second email, received a reply from Hiromi, who transferred me to the US representatives -- Wayne and Denise. They never replied to my email.