RadCom April 2024, Vol. 100, No. 4

50 April 2024 Review I had been looking for an antenna to replace a 38-year-old Butternut vertical antenna, which had seen one too many winter storms here in Pembrokeshire. As I asked around for recommendations, one name kept coming up: ‘DX Commander’. Their antennas have gained a good reputation for performance and value for money. What is it? The Signature 9 is a vertical antenna which covers 10m to 40m without an ATU, and offers to cover 6m and 60m with an ATU, and perhaps even some local coverage on 2m (see Figure 1 ). Prior to the arrival of the antenna, I decided to take a look at some of the DX Commander videos [1] showing the assembly of the antenna. These are quite comprehensive, helpful and certainly entertaining. I must admit I finished watching the video about assembly and thought: “Crumbs, there’s quite a lot to this!” It wasn’t just me; Roger, GW5NF was visiting and watched the videos with me. At the end of it, he said: “Tim, you’re going to be busy.” DX Commander don’t send a set of instructions out with each antenna, but there’s a PDF that you can download from the website [2] . Make sure your printer has plenty of paper and ink: it’s 34 pages long! In fact, the manual you download covers all the DX Commander vertical antennas, rather than just the one you’ve bought, which again gives a sense of complexity. On the other hand, the download approach allows design changes to be updated immediately. Assembly My first task was to create a base for the antenna (see Figure 2 ). A ground post is supplied. Because of the nature of the ground here (rocky), I opted to dig a hole and set the ground post in ‘Postcrete’. Callum, M0MCX, suggests that many users will not set the base in concrete, initially at least, but drive the post in and let it settle. I would have tried that approach, but for the nature of the ground here. Nevertheless, I dug a suitably- sized hole (which took a while), and then set the post in the cement, leaving it a couple of days to dry. I began to assemble the pole while the post was setting. This was not difficult: I could just unscrew the top and pull the sections out, twisting them to secure them. As the antenna was going to be up permanently, I used the supplied clips (these are the HCL ‘EzyClamps’) to stop the pole sections collapsing. The clips are plastic versions of jubilee clips; you twist a screw thread which tightens the clip, but they don’t bite you like a jubilee clip can! They are effective, but slightly annoying as you get used to them, especially a bit further up the pole where it narrows; do cut them down with some snips to make tightening them up a quicker job. Higher up still, I used some tape over the pole-section joints along with some cable ties, to secure the sections tightly. Once assembled, you can then slip the driven plate at the bottom of the antenna down onto the base and secure it with a clamp, followed by the spreader plates which find their own positions on the pole, again clamping these in place. Around this time, I was looking at the instructions and wishing DX Commander Signature 9 FIGURE 1: The antenna being assembled on the ground.