I have been running PiAware now for a couple of weeks and am currently using the telescopic antenna that came with my NooElec NESDR Mini 2 USB RTL-SDR & ADS-B Receiver set from Amazon.
I am quite amazed at the performance of this antenna sitting on my north facing windowsill just 5 feet off the ground with trees right in front of the window.
However I find the message/distance distribution pattern interesting.
I live on the east coast of central Florida and PiAware is stating that I see and average of 800 to 900 aircraft a day. What’s more interesting is that I see lots of flights in the <60 mi range, fewer in the 60-120 mi 120-180 mi and 180 - 240 mi ranges, nothing in the 240-300 mi range but quite often see several in the 300+ mi range !!
Is there any reason I would be regularly seeing flights 300+ mi out but nothing in the 240-300 mi range ?
To be honest it’s incredible I see anything 300+ miles out especially since many users in the forums are struggling with fancy antennas to see half that far. Perhaps its a function of Florida being so flat and being near the coast.
Anyway, I ordered an FA antenna from Amazon and will pop that up on the windowsill for a comparison. I plan to hook the antenna directly to an N to MCX pigtail with the NooElec USB adapter mounted close by and a 1M USB cable from the NooElec back to the Pi to minimize cable loss.
I will post an update after I have the new setup running a few days.
Interestingly enough, I’m running the crappy stock (non-telescoping) antenna that came with my dongle out here in ABQ, NM, and I’m getting similar results (mainly from the Embry-Riddle Aeronautical University birds out at Prescott, AZ)… but I’ve got a ton of hits from that 300+ range and the rest are confined to rather close-in (as would be expected).
Seeing birds past 300 but nothing in the 240-300 range? One would expect things to be piecewise-continuous to a certain extent…
Possible, but not likely – I suspect you’re running the old/stock dump1090 client. This client has some problems, particularly in filtering corrected messages – they’re error correcting code failures. As an example, on one occasion when I was monitoring messages from the old client, I saw reports of aircraft out 1200 miles at an altitude below 5000 feet. This is not geometrically possible. The new dump1090 client adds more sanity checks and a max range limit. This max range limit is based on physics and spherical trigonometry.
The bad news in going to the newer client with more sanity checks is that your numbers will probably go down a bit down. The good news is that drop is a drop in garbage messages.
Interesting… He is running PiAware (SD Card) 2.1-2. I guess all the surrounding ocean in southern Florida might be helpful. Or there are some local aircraft reporting incorrect GPS data?
Correct, I started with 2.0-4 (from the SD card download) and it has been auto-updating correctly up to “Feeder Type: PiAware (SD Card) 2.1-2” on it’s own yesterday.
I am assuming the auto updates update everything necessary and that no additional manual updates of certain components are required. (I hope so as I am a newbie).
Check my July 9th data report. There are 49 hits at 300+mi.
I have had a few reports of sporadic 400NM contacts that seem to be plausible data; but that’s with unusual atmospheric conditions, it has to be some sort of ducting effect going on as they’re well below the horizon at that point. Most of the time if you get >300NM it is, indeed, most likely to be bad data (either in the receiver or in the transponder).
During the past 10 days or so prevailing winds have carried smoke from the forest fire in Saskatchewan east over the Gulf of St. Lawrence and during it’s peak I was seeing several flights out to about 320NM. But with a change in the weather patterns it has subsided.
…Tom
Over open water, ducting can work – as a ham radio operator, I’ve worked Hawaii from the West Coast on 54 and 144 MHz. 1 GHz events are definitely possible but I wouldn’t expect them to be every day.
FWIW, the antennas that come with NooElec SDRs are capacitively coupled magnetic mounts. Weak magnets, but they do stick. Attach the antenna to something metal with a radius of at least 1/4 wavelength (6.9 cm ) to give the antenna an effective ground plane. Steel is easier since it’s magnetic, but even a sheet of aluminum will work if the antenna is mechanically attached without adding anything between the antenna mount and metal.
I tested the Android flight feeder last weekend out in my front yard while holding the antenna in my hand. I stuck it to my car and the number of frames per second immediately increased threefold.
I put the new FA Antenna up on the windowsill in the same spot as the whip antenna last night so I will report back in a few days.
Eventually I will move it outside and up on a mount but need to check the HOA regulations first LOL.
I have been running the FA antenna on my windowsill since Friday night in exactly the same location as the telescopic whip and so far am not sure what to make of the performance.
I am seeing on average approximately 200 aircraft / 8500 positions less per day since switching the whip to the FA antenna.
The two setups are slightly different but I think the FA antenna setup should be slightly more optimal (at least the same) as it is connected with the lest amount of coax (less loss) and the highest gain antenna.
(1) Whip setup
Mounting Location: Windowsill
Included coax cable from the whip to the Nooelec SDR
Nooelec SDR connected directly to the USB port in the Pi
(2) FA Antenna Setup
Mounting Location: Windowsill
N to MCX pigtal used to connect the antenna to the Nooelec SDR
Nooelec SDR connected to the USB port in the Pi via a 3.3ft (1M) USB extension cable
Could the 3.3ft USB extension cable be the issue ?
The FA antenna will have a much broader and flatter reception donut than the whip - make sure it is mounted vertically or the planes might not be in the inclined donut.
Installed and ran kalibrate, R820T2 only off by -2 ppm
Put the telescoping antenna all the way down instead of all the way up - surprisingly noticeable improvement
Changed to dump1090-mutability and enabled basically everything (aggressive, phase enhancement, etc.). MLAT went live, and I like the plane color corresponding to altitude.
Built 8 element coaxial collinear antenna (not terminated on the end, no bare wire on the end, less than 1m to F connector, short F to MCX cable to R820T2) 50% improvement over telescoping antenna
Installed inline 20 db amp (from Amazon: Paladin 9672 & Directv 21 volt power inserter for swm integrated lnb) 100% improvement over previous config
At this point I can’t put an antenna outside in my neighborhood, so I think I’ve taken it about as far as it’s going to go.
If you have a telescopic antenna it is definitely worth adjusting how much of the antenna is pulled out to get it closer to the 1/4 wavelength size. Nice and easy to adjust to get the optimal signal.
