At any given time (in the evenings), I see 1 to 10 aircraft. I'm about 10 mi away from the major airport.
See a lot of zeros.
Some give their flight number
Some give their alt.
Some also give lat/long, track and/or speed.
A fraction give all of the info. Certainly see a lot of 0's for the data.
Interestingly, I now have one that has zero for the altitude (a4b15d).
After typing that up, now there are two more with zero altitude. And one of them is on a heading of 259 doing 422 kts.
Don't know if this thing has problems decoding or if the aircraft isn't sending all of the data. The default for dump1090 is max gain & no AGC.
I'm too far from the ground station (assuming its at KMSP) so I wonder if its giving useful data to fill in stuff so the a/c doesn't have to.
Seeing FDX320 from Memphis to Grand Forks at 38000', 453 kts, and a heading of 334 deg. Confirmed that with PlaneFinder.net. Lat/long had been 0 for a while on it, but they eventually filled in. And after that, it populated the flight #. Hope he has a little fun and tunes into Kenie (AA) on 365 kHz in Fargo.
Also seeing a couple of MN ANG C-130s... GOFER22 & GOFER03. Both of them have all zeroes.
Meanwhile, VIR20F (SFO-LHR) has all of the data and CKK234 (China Cargo Airlines, ORD-PUD)
For a brief moment, one aircraft was at 7375'. Looked at that number and though back to the last frequency Radio Croatia used to broadcast to us a couple of weeks ago. Miss them, a lot.
Still just using the little UHF magnetic antenna that came with the USB stick. Gets the job done for now and will be perfect when I zip by the airport one of the these days with the laptop and see if I can get any other data. Also need to find out were the ground stations are around here.