Comparing Antennas
2020-07-18 I got lots of feedback when I posted the report below on the Antenna Building Facebook group. Clearly this was not a carefully controlled lab quality test. It's just a simple, brief, comparison with the antennas in my back yard.I did this more or less just for fun. After weeks and months using all these I have my opinions about how great they each work for me. Interestingly, even this brief test supports those. I agree with some commentators that a true test needs a highly controlled lab.
This was less about the antennas themselves and more about my whole antenna environment. You might get somewhat different results at your QTH because of factors like terrain, ground conductivity, etc., and of course propagation! As hams our primary goal is to find the antenna that "works great for me!" I'll probably do more of these experiments just with the verticals since that avoids issues such as directivity and orientation.
A decision I have to make every time I take my rig off-site is, which antenna(s) to take? The short vertical is sort of wimpy and embarrassing! A full sized link dipole is a bit complicated and needs space. A ton of long radials are trip hazards. But I have to decide by a week from today when I go camping with my grandson and his 12 friends along with my son, his dad!
2020-07-17 A question I get occasionally when I talk about a specific antenna is, "How does it compare with ... ?" That's a really difficult question to answer meaningfully. It's easy to compare the relative ease of setting up, portability, etc. But when you come to performance, I don't think I've every had any idea how to actually determine that for me in my situation. Like everyone I have my impressions and opinions. Yes there are many references on the subject and they are generally useful. So most of us likely have the impression that a dipole is a "better" antenna than a vertical, for example. But then other factors must be considered. A dipole is not always possible. So the question really has to be altered to take the situation into consideration.
It's in that light that I recently made a very short (about 6 ft extended), bottom loaded vertical. It's advantages are that it is very small and light and extremely easy and quick to deploy. It is a little bigger than shirt pocket size but not a whole lot.
A couple months ago I made a 1/4 wave wire vertical that has bottom loading coils for 30 and 40 meters. When packed up It is almost as light and small as that short vertical but takes a bit longer to deploy and requires a tree, push-up pole or something to suspend it from.
Months before that I was into very light weight EFHW wire antennas. The advantage is that in performance it rivals a dipole, is multi-band and is easy to feed since the feedline connects at the end instead of the middle. It set up as an inverted vee it is almost as easy to set up as the wire vertical. It's main disadvantage, like a dipole is the space it requires.
I use them all and like them all. But my impression is that they differ considerably in performance. I believe performance wise from best to worst I'd rank them EFHW, long vertical, short vertical. But I thought it would be interesting to attempt to compare them using the Reverse Beacon network.
So I set all three up in my side yard. Both verticals have the same length of coax. And while I was at it I added my G5RV and 1 meter magnetic loop to the mix. The G5RV and EFHW are permanently mounted in the yard. The loop was inside the shack for the test. The EFHW is an inverted vee strung north-south. The G5RV is strung flat top East-West. All my tests were run at 5 watts and all feedlines come into an antenna selection switch.
The file below shows the results of the tests I ran. They are far from conclusive but are my first attempt to actually measure performance. The results support what i already thought but are still interesting. I tried to do some receive comparisons but the few signals I heard today were totally unstable. maybe some other time.
| 2020-07-17_antenna_comparison.pdf |