A year or so ago I bought the HB9CV from Moonraker, The antenna was easy to put together, but the instructions are not very clear, you have to work out yourself how to fix the driven element. Inside the terminal box is an air spaced 'beehive trimmer' - not seen one of these for years! The trimmer is used to tune the antenna to obtain best SWR. This I found quite straight forward. This antenna has a rear mounting bracket, which is fine, but the supplied clamp was poor and even when fully tightened the antenna keeps dipping down. The extension rods have to be tightened with the screws fitted, I still don't understand why this kit has extension rods, why couldn't they make it all in one piece?
The antenna is nice and light and will work well either as a base antenna or as a portable antenna, these antennas are of reasonable price but I have included measurements and a link to the “HB9CV” calculator site.