I’m looking to add another feeder that will be located outside on a shed. I was going to set it up with both 1090 and 978 but I was curious about how to mount the antennas. Can I mount both the 1090 and 978 antennas on the same mast or will they be too close together? Suggestions on how to put some distance between them, if needed?
There has recently been some active posts regarding this very same subject. I can’t recall the title of the posts to get you there directly, but I will summarize. Yes, you can support two “separate” antennas on a single mast by using a crossbar attached to the mast and the individual antennas out at the ends of the crossbar. The key is to provide adequate separation between the antennas and the figure I recall is a very minimum of 2 feet separation. I would suggest you do better than the minimum to allow for a comfort zone.
Thanks, I was just reading over that thread.
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This is definitely ideal, but it’s not the end of the world if you don’t get that separation. (obviously it would be better…)
In my case, I have an FA 1090 antenna attached to a satellite dish mount near the peak of my roof. It is typically 1st or 2nd in total aircraft among my local feeders, and usually 2nd in positions. Right at the moment it is tracking about 70 aircraft and receiving ~450 msgs per second. Median flights for the last 7 days is 1,037 and median positions is a little over 302,500.
I share all of that because I also have an FA 978 antenna attached to the very same tube. It’s mounted about 3 inches higher and there are about 4 inches of separation between the two antennas. The 978 obviously picks up a lot fewer aircraft, but still pulls in 50-100 flights per day and 15,000 positions.
Would it be better if they were a couple feet apart? Probably. At least maybe. But the 978 antenna is on the east side of the 1090 antenna, and most of the commercial traffic I see ranges from directly overhead to the west. Most of the GA 978 traffic is flying in circles, so I’m pretty confident that I am not missing a lot of those.
Pic is not a great angle, but you get the idea.
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Never the end of the world, it’s a hoppy after all. I just like to try and maximize my system’s ability to track aircraft in all 360 degrees of the reception window and reach out just as far as possible in all directions. If I think I can possibly improve my coverage by separating antennas or improving the signal quality with an improved coax performance rating, then I will work to obtain parts and insert them into my system in a test-controlled sequence so that I can hopefully measure results and proceed to play from there. What I have found useful is to monitor the live aircraft tracking in the Piaware Skyaware display and watch for the tracking communications for the aircraft furthest out in my most challenging directions. As you watch these aircraft on the fringes of your reception, you will see aircraft images fade in color as their signals begin to fail to register with your antenna and receiver. Eventually, they fade and disappear from the tracking screen. This is a good way to measure the ability of your complete system to achieve maximum range relative to signal capture. I recently raised my antenna 3 feet to try and improve my look to the south because of the house roof ridge being uncomfortably close to the height of the antenna. That 3 feet made an incredible improvement in the number of aircraft I was able to track to the south beyond 200 and 250 nm. Good fun being able to measure results. The 1090 Graphs tool is also a great piece for the tool bag but that is pretty well documented here. If you get tired of venturing up on to the roof, I suggest you mount your antennas on a mast that originates on the ground and passes up the side of the house above the peak and allows you to lower it to a more serviceable position as required.
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