I currently have this antenna and was thinking of upgrading to the 1.2 meter version found here.
From what I can tell, the only difference is the 50% height increase, as well an increase in gain. They are the same brand, etc.
If I were to replace the 0.6m one with the 1.2m one, and install it in the exact same location, would there be a noticeable increase in range/messages?
My stats with my current antenna can be found here. I’m happy-ish with it at the minute, but am hoping to squeeze a few more miles out of it if I can. I have an Uputronics 1090mhz preamp installed, too.
The outside line represents the maximum theoretical range. The highest range I have received is just under 200mi. You can see the beginning of the tracks is about 120-150mi, which is the average for me.
That’s with the 0.6m aerial, which does have some obstructions. The 1.2m one would be above these obstructions so should have an overall higher range?
At 1090MHz, the radio path is very much ‘line of sight’. The final limitation to range is the curvature of the earth - meaning, even at cruising altitude, you loose signal because the plane has dipped below the horizon. This is made considerably worse by local obstructions (building, trees etc.), so getting your antenna up above local roof-lines will give you the best shot at distant flights.
If that’s true so would the 60cm one you currently have if you added a 1.2 meter long or longer mast to your antenna mounting setup. A lenth of scrap water pipe or 4x4 lumber would do. Save your money for now and work on getting your current antenna above the level of those obstructions. Once it has a clear line of site to the horizon in all directions then you can consider getting an antenna with more gain (assuming that these are collinear antennas and the longer one has more elements therefore more gain.)
By the way the longer antenna achieves that increased gain by having a flatter radiation pattern (“radiation” if it were transmitting, but the pattern is the same whether transmitting or receiving.) The radiation lobes of the shorter antenna go higher up in the air than the longer one so might be allowing you to pick up planes just above the obstructions. If your current antenna already can’t see the horizon very well due to obstructions the longer one might even perform worse at your location because it’s blocked more by those obstructions than the small one, having radiation lobes that are wider (hence more gain) but also lower/flatter.
