Hello to everybody.
I’ve already a flightaware antenna, a raspberry pi4, a smartee v2 and a rtl-sdr blgo LNA, but i want to upgrade my receiver and the components that I will no longer use to put them on another receiver, which would therefore be less powerful and secondary.
ok, and what is your question? How can the forum help? What is your expectation to an upgrade?
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could you suggest me some components that are of a good level?
Now I have a coverage of about 150km, I would like to reach about 400km
If anyone can tell me the measurements and materials, I had also thought of building a yagi antenna to point towards the nearest airport
First you need to identify your geographical limits. You cannot go beyond tehem with equipment only. The 400 km cannot be reached if the environment does not support it. My max range is slightly above 300 km due to that.
Did you check heywhatsthat.com already for it for generating a profile?
And please check this thread where your topic is already discussed:
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yes, i’ve already checked and i have a maximum range of about 230 miles
In terms of receiver, you could try an AirSpy:
Don’t forget the “Law of Diminishing Returns” though.
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No one gonna say coax first?
Not me. My recommendation is not deemed good enough. 
My first comment is, what’s your budget?
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It depends on how much better I would have!
For example do you have antennas to offer me?
What is it?
If the antenna is outside and can see the horizon, you are doing sth wrong or the LNA is defective.
Post some statistics:
GitHub - wiedehopf/graphs1090: Graphs for readsb / dump1090-fa / dump1090 (based on dump1090-tools by mutability)
Do a spectrum scan:
https://forum.flightradar24.com/threads/11450-Do-I-need-a-Filter-Find-RF-Signals-In-Area
Can you show the coax you are using, especially the SMA end?
A link to the EXACT product you bought will also do.
The principle is that improvements in performance become increasingly expensive the more you spend. For example, you can buy the cheapest dongle and use a home made antenna with a bit of tv coax and get a working receiver. It doesn’t cost all that much to get a better quality dongle, reasonable coax and an antenna.
Spend more, and you can get an airspy, an lna, better coax, maybe a better antenna.
Then to improve performance more, you have to start spending a lot more - maybe a hardware based receiver like a radarcape, a precision cavity filter, higher quality coax etc. But the improvement you see won’t be anything like what you see going from the cheapest dongle to the airspy, and you will have probably spent 3-4 times as much.
The same applies to pretty much everything. There will be a point where spending more money doesn’t buy you enough improvement for it to be worthwhile.
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I think you already have a good antenna. There are others, but I have no experience with them. There is so much even a good antenna can do, after that, it’s all ‘snake oil’.
As for the “Law of Diminishing Returns”, what it means is that the improvement cost becomes too high for the benefit gained. Most people have budget constraints, but if it’s not your case, go for it.
Another popular saying that I like is this: good, fast, and cheap. Choose 2, because all 3 is almost impossible to find. 
One of the best antennas is the one sold by Flightaware in Amazon.
Because you already have that, you need to have it mounted high enough to be above the obstacles around you, that will be the best upgrade.
After that an Airspy and a filtered LNA will help squeezing the last drop of ADS-B signals that reach your antenna, but they can’t bring in whatever is not captured by the antenna.
PS: I have replaced a no-name LNA with the same one like yours, and the actual gain decreased. I think I will have to replace it again with something better.
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I believe that my antenna, after many discussions and tests on this forum, works well.
Also because today I tried to mount it temporarily outside and the coverage has increased significantly, in one direction it has reached about 300km
if you read this my other topic (link) you already find all this, but in my opinion there is no need to check. however if you prefer I send you everything.
One question, how can I select the correct gain?
Can anyone compare the flightaware antenna with this airnav radarbox antenna?
antenna
Oh right.
If it’s this spectrum scan:
Then either your SDR or the rtl-sdr LNA is defective.
That’s not how it should look.
Why don’t you do another scan now that your reception is a bit better?
Looks better.
Don’t have a reference right now for a similar system at gain 30.
Anyhow, you seem to have components that should produce better range than 150 km.
Are you sure it’s not houses or trees around the antenna that is blocking the view?
Is the antenna on the roof or inside?
In this moment no, i don’t have it but tomorrow probably i might finish the antenna setup (outside) and i will do a test.
I think it’s the position of the antenna, which is inside the second floor and the environment that causes all this.
The walls, even the windows (especially anti-solar treated), they all attenuate the 1GHz frequency. So yes, putting it outside will bring nice gains.
Do you need VHF Airband 118-136 MHz?