First of all, the sections of aluminum tubing are held in place by hose clamps. These tend to loosen with time and vibration. Once I had the thing adjusted and tunable on all the bands I work on the radio, I put a sheet metal screw in each section near the hose clamp to make sure the sections don't slide down and de-tune the antenna.
An antenna this long (43 ft.) tends to vibrate in the wind especially if it has guy ropes attached to it. I would not recommend installing it without guy ropes, especially in windy climates like Illinois has. The vibration tends to loosen clamps and other components.
The balun box is poorly designed. The box is held in place at the base of the antenna by two hose clamps which also serve as contact points to the antenna. This is not a good thing because the clamps tend to get dirt behind them and the aluminum of the antenna tends to corrode there. To fix this issue, I disconnected the wire that feeds signal to the hose clamps and terminated it to a stainless steel bolt which I installed in the side of the box. See figure 1. The cable I used for the outside connection to the antenna is plain old #12 copper wire. The cable you see in this photo is the center conductor of LMR-400 coax. It dry-rotted over time and I had to replace it. I then connected the other end of the cable to the antenna by means of a 10-32 stainless steel screw tapped into the side of the antenna.
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| Figure 1. |
The next thing I did was to take out the two blue capacitors and mount them to a circuit board and re-solder them into the box. One time I could not figure out why the antenna would not tune, so I looked inside the balun box and discovered that one of the wires from the capacitors had broken off! This was puzzling to me, but I figured out that it must have been vibration that caused the connection to weaken. Putting the capacitors on a circuit board then soldering in some heavier wire for the connection to the coax connector cured the problem. See figure 2.
Next, I found that the ground wire connection to the base plate of the antenna was not very good. I had mistakenly used a zinc terminal on the end of the earth ground wire to connect to the base plate. These two metals don't like each other. I took the terminal off and installed a connector made of an alloy that is friendly with copper and aluminum. I bolted it on with a stainless steel bolt and then polished up the end of the ground wire with sandpaper. Then, before inserting the end of the copper ground wire, I smeared some Gardner-Bender No-Ox on the end of the wire. Then I tightened the connector's set screw. See figure 3.
Figure 3.
Make sure you don't forget to insert the black wire from the bottom of the balun box into the connector as shown.
These improvements have made a big difference in keeping the antenna in good condition and functioning normally. Remember that using stainless steel bolts and other hardware are the only way to go when constructing antennas. They don't corrode or rust and you won't have to replace them unless they break.
73. Your comments are welcome.
