Setup suddenly not working well

Hi- about 3 days ago my setup started finding far fewer planes.

I have Intel nuc > blue fa stick > blue fa barrel filter > bias t > cable running outside > amp > fa antenna.

My best guess is the amp because it has been raining here to beat the band and I’m wondering if the rain finally fried the amp. I’m going to remove the bias t first to see if I get better reception. I’d try and remove the amp but it would require climbing so I’ll wait on that.

Edit: removed the bias t. It’s still bad. I’m going to need to climb and remove the amp and see if it gets better. If so it’s the amp. The # of planes I get is even worse than when I had just an indoor antenna so maybe a fried amp is blocking most of the signal… That’s my best guess. And I guess if that doesn’t fix it I’ll simplify my set up until I find the answer unless someone has a better idea.

Anyone have any better ideas? Here is the graphs 1090 from the past week.

Well, I solved my own problem. I climbed up. The lna was fried. Any ideas on how to waterproof my next lna? I guess tons of electrical tape didn’t work.

Also does the lna need to be right after the antenna or can I have it inside nearer the computer?

I prefer to keep everything electronic inside the house. Antenna and 400 coax are the only things outside. There is a waterproof sealing tape called “Rescue Tape” that I use to seal all outside coax connectors. Other brands available also depending on where you live.

I guess the dumb question is I can have the LNA inside? Ie it doesn’t really matter where it is, ie right next to antenna or inside before all the other stuff? (I’m not looking for super maximum setup. Just “good enough”)

Graphs look better.

Looks like you are back in the game! I prefer to install filtering and amplification after the signal has passed along the quality 400 coax and is just entering the receiver. Some consider it amplifying noise and I consider it filtering after passing along the coax. Plenty of opinions on that one. Then there is the opinion vs fact discussion. I can agree to disagree.

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do you arrest common mode current before the filter with a ferrite choke? I’m in your camp, and do my filter & amp as near the receiver as practical. It’s just where I want the prettiest signal, is all.

I use some ferrite chokes in my radio hobby wiring but have no chokes installed with this Flightaware receiver system currently. Are you utilizing a choke to any effect?

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when I was young I would think about what would keep me warmer – the order of the blankets/sheets on my bed. And I think the answer is in the end one way may keep you like 0.1 degree warmer, but on the whole it probably doesn’t matter. But there were probably people who very much thought that one camp was correct vs another camp’s proponents. so that’s how I’m going to view my FA setup and I’ll be now in the camp of putting all the electronics inside so I don’t need to keep replacing my lna. :slight_smile:

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I concur that is a completely defendable logic. I well expect you will enjoy the benefits of avoiding the wet and extremes of temperature.! Your system will thank you.


I use a small electrical junction box. It’s worked well enough over the last few years.

Ideally the LNA should be as close to the antenna as possible, since that’s where it will have the best effect on signal to noise ratio. Having the main length of coax the receiver side of the LNA means that the loss from it and noise induced by it is much smaller than the amplified signal. If you have the coax prior to the LNA, the loss and noise from it are much more significant because you are amplifying them along with the signal you want.

If your coax run is particularly short, then you won’t lose too much, but if it’s quite long, then the difference will be more noticeable and the quality of the coax you are using will have a much larger impact. You can still get pretty good results with the LNA near the receiver though.

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With radio it does actually make a difference, and there is a way to calculate what that difference is. Here’s a post I made about it some time ago: HOWTO: Airspy mini and Airspy R2: Piaware / dump1090-fa configuration - #930 by caius


The LNA can be also at the end of the cable connected directly to the stick.