Try this one:I was looking into it because I wanted an all black version instead of the typical shiny chrome whips and also didn't know if it was one of those bogus Chinese knock-offs.
Sounds like it isn't a very good performer.
Yep, not so great on airband. I kind of went overboard on analysis earlier:My listening consists of mainly the air band and 800mhz. I had hoped I could adjust for the one I was monitoring. I found this antenna did no better on the VHF and air band than my Radio Shack 800 rubber duck. YMMV
There is no real magic to telescopics from one manufacturer to another.
One typically adjusts it to either 1/4 wave (234 / f mhz = feet) or possibly 3/4 wave for a "dual band" that works out as a 1/4 wave on one, and a 3/4 at 3 times that length.
All you need for vhf airband monitoring is about 22 inches minimum. For milair, with it's super wideband nature, at 300mhz that is about 9.5 inches. If your milair interests are primarily lower in the band, then you can calculate for that frequency, and of course also for the higher frequency activity. But generally, 9 inches is a good compromise for your typical handheld setup near to the milair activity no matter what the frequency.
However, if you buy junk, counterfeits and the like, you may find that the manufacturing process is shoddy, like there not being an actual connection from the center pin of the bnc to the telescopic itself. THIS is what can lead to one proclaiming that a Diamond telescopic beats the pants off some off-market deal too good to be true.