Improved ground spikes for HF vertical antenna
In my previous project I made a portable antenna to use with my HF radio. In that project I built ground spikes that allow the antenna to be secured to the ground by just pressing them in. I used 3/8th steel rod to fabricate these. This had a number of problems:
- These ground spikes are very heavy
- They are very difficult to drive into compacted or dry earth
- They can be difficult to get out
So I needed to fix this. I found some round 1/4 inch steel rod in my metal supplies. These need to be welded to 1/2-13 bolts to install into my antenna mount. In order to make these lighter, I decided to drill out as much of the bolt as possible. As it would turn out, even cheap bolts are much harder than what I imagined. I broke a few 1/16ths dril bits, then broke several 1/8th drill bits. At that point I decided I would just go straight to a 1/4 inch drill bit. This actually worked with a regular HSS bit. My 1 HP drill press turning at about 500 RPM was able to drill down around 1 inch into each of the bolts. I used a bunch of ATF as lubricant, which often boiled away from all the heat this caused.
At this point assembly was basically the same as my other ground spikes. I use a metal file to flatten the top of the bolt head and remove all the galvanized metal. After welding everything is cleaned with a wire wheel. Then I put a slight point on the end of the rod to make it easier to push into the ground.
These wound up being much lighter and work great. You can see I used two different lengths. The reason for this is only 1 ground rod is really needed, the second one is just to stop the assembly from rotating. Since the lengths are staggered you can get the first rod into the earth before the second starts to contact.