Comment by rootusrootus 4 days ago
> They might choose to use a public ADS-B aggregator site because it gives them situational awareness
I do not understand what the upside is, aside from saving a tiny amount of effort and cost -- they could get the same data with more reliability by just running their own ADS-B receiver, without having a dependency on a third-party.
All good points. I'd set it up very near the airport but not on it and then access it using the same web browser that I'd use to go to ADSB Exchange.
> I'd set it up very near the airport but not on it
The problem is, you need to have a good height for the antenna - "height is might" in radio, particularly above VHF bands. I actually can see this with my own ADS-B receiver - I'm in a valley and precisely can see that effect when plotting received packets.
I get good distance from my ground level antenna, but while I'm in a valley, it's very wide and long. My assumption is that most airports are going to be in fairly flat areas.
The original point was that you become reliant on a public service, probably run by volunteers, for something halfway critical to your operation. Doing it yourself is easy and then you control the reliability, not someone else.
Imagine your boss doesn’t like you looking at ADS-B sites because it’s not data from an FAA approved system but as long as you’re discreet and not actually breaking a reg they don’t yell at you. Then they come in and see that you installed an antenna, RTL-SDR, and raspberry pi in the tower.
> they could get the same data with more reliability by just running their own ADS-B receiver, without having a dependency on a third-party.
Setting up an ADS-B receiver is indeed very cheap. Less than 100$. That's what many people, both aviation enthusiasts and ham radio operators, do for fun.
The problem is, do that on an airport? You'll now need permits to install the antenna (needs to be covered in the lightning protection system and even if it's just a passive receiver probably someone needs to sign off on an antenna being added). Fire code means you'll need approval and specialized people to run the cable (you need to drill holes in fire walls). Maybe there's some law or regulation requiring approval or causing a paper trail (e.g. in Germany, all electrical appliances have to be isolation-tested and visually inspected every two years by an electrician). Doing that the proper way is an awful lot of work. And by that point, someone will notice "hey, a Raspberry Pi? An RTL-SDR stick from eBay? No way that is certified to be used in a safety critical environment", killing off the project or requiring a certified device costing orders of magnitude more money.
In contrast, a privately owned laptop, tablet or phone with the Flightaware app? No one will give a shit about it unless someone relies on FA too much, causes an incident and that is found out.