You are right about overlapping. I see, having smaller groups of planes by handling them in sectors, and in stand-alone station per sector will reduce overlaps.
…at the end, these stations (4 to 6 or even more of them altogether) will be better than ONE station alone. True.
It is not the best deal for a hobbist. Making a single station a bit more shiny than it was before is exciting enough for me. (I do not want to give up catching fishes and other hobbies for having and maintaining several stations.)
The ADS-B system isn’t too old, but it seems to easily reach its own limits. I think it is likely that communication procedures and methods will sooner or later be further refined.
I have to mention that some amateur stations perform better than smaller airports.
Edit:
Sorry, I forgot the initial criteria → “without cost limits”
Yeah, ADS-B is not signal limited and even modest systems can receive out to their radio horizon and beyond quite easily. As wiedehopf pointed out, the purpose is to reduce overlapping signal.
That may not improve overall tracks significantly for ads-b, but one area it might help with is mlat, which requires receivers all see exactly the same messages from the aircraft. Reduced overlap increases the number of messages available so might improve mlat fixes.
Biquad is a well known antenna type with great diy construction possibilities, but in this size we need some weatherproof solution - thinking of snowing and other bad things in winter.
Agree.
Sector antennas have their purpose.
Where coverage of distant stations dictates, I could accept them as a solution, or as part of a transmitter system in airports. (Interogations in sectors,one by one to reduce radio traffic. Transmission on 1030 and receiving answers on1090)
You always have interrogation by a rotating radar head to get direction from that.
Combined with time to response reception you get the location to check that ADS-B position isn’t being spoofed.
There were plans to get rid of that but it turned out that you can’t get away from it.
This page will show you the last or current position of aircraft which lost GPS in the last 15 min.
Civilian aviation continues to work just fine.
Especially for limited areas the inertial reference system will be more than sufficient for en route navigation.
…
The sector antenna can handle 5 kW transmission power
This might be for ASDE-X surface MLAT systems for aircraft on the ground at airports? I simply don’t know.
…in my neighbourhood, in Ukraine there is a war. I think, they both use GPS jamming to make it harder to deliver evil things. In these areas civil aviation does not work now, but earlier passanger carriers were passing by. I do not know if they had manipulated the GPS signals - but in Doneck a plane from Taiwan was shot down…
Ah, yes. I heard about it. → Is this for clearing bad situations - creating interoperatibility - among a mixed Flarm, TIS-B, UAT and ADS-B enviroment?
Sorry for my bad English
Only one i know who has an airspy and a radarcape is @foxhunter
And he’s pretty limited by geography / doesn’t have a good splitter or 2 comparable antennas i believe.
To know the airspy is miles better than an rtl-sdr for ADS-B … you barely need to do a comparison for that, i believe @caius has shown the most impressive differences due to the coverage he has.
I know someone who has a ModeS Beast but no airspy and while he’s done some comparisons in the past, he was more interested in the antenna side, not sure he’d be interested in doing a comparison.
Hmm someone on here had lots of antennas / devices and was doing comparisons but i don’t remember who.
That’s DF11, you can see by the numbers at the bottom (it shows the current value, so at the right side in the graph, DF11 halfed is at 133 (so DF11 is at 266).
High DF11 rates are usually associated with Europe where it’s indicative of lots of radars doing interrogation.
So i’d expect someone tweaked the ATC radar interrogation rate or there was some error.
I would like to do a comparison test with the FA Blue stick and Airspy but I only have 1 good antenna, at 70 ft height since late April. I don’t want to add a splitter this week because the sun just came out for the first time in 10 months. Things just finally starting to happen on my station!
I guess -3db might not be bad. But I’m severely mountain and forest limited. We need someone up in the clear to test.
I remember Airspy gave a huge boost in positions over FA Blue for my challenging tree situation. So maybe a distorted location is actually a good test reference too.
Well here’s something - I compared 30 days in September 2019, which is when I first put the antenna on the roof with using the airspy with 30 days recently. That should cover all the optimisations done to the airspy decoder since I started using it. I think the first changes came in October 2019, then there was a gap with the more major optimisations happening at the end of last year.
The difference in performance is just from software optimisation, as the hardware has remained consistent throughout. The difference even back then between the rtl-sdr dongle was pretty big, so now it will be even wider.
A 3 dB loss after the high gain preamp will not degrade the system noise figure (NF) by much. Maybe something around 0.001 dB. In comparison, a dirty connector can cause up to 3 dB degradation of thr NF.
