Works nicely, of course a good ground plane improves the antenna. Upper frequency when completely inserted is around 500MHz (Limited by λ/4). Completely extracted it has a radiator length of 47cm so it's a bit to short for the 2m HAM band. Normal shipping time (3 weeks)
took very long to arrive. Perfect! Collapsed: only on 433 MHz is the SWR OK. Fully extended the SWR on 145 MHz and 433 MHz is OK