Hi all,
while I’ve been interested in flight tracking, I’m a very new owner of a receiver myself.
I’m using the most basic setup with a RPi, DVB-T receiver and antenna and I’ve just started feeding Flightaware in addition to FR24.
FR24 shows a max range of about 250nm which I guess is already quite good. To give some context:
I’m based near Frankfurt, Germany with an antenna elevation of about 435m/1427ft and according to heywhatsthat I should be seeing planes near Monaco at high altitude (which I have seen but have not been picked up by my antenna). So far, the furthest I’ve seen was around Geneva.
Obviously, map-based calculations are just the theoretical max. Given that the Alps are between my house and Monaco, I also doubt the accuracy of the map.
However, I’m wondering whether the purchase of better hardware would make sense or if I’m already seeing most of what’s in my line of sight.
So what I’m asking is: How big is the difference between what the map is showing versus what’s realistically possible?
It is totally dependable on your location and the elevation of your antenna.
The map shows a theoretical maximum, this is also depending on the equipment used.
For instance, a dedicated sdr flightstick with an amplifier and filter will give you better results then a generic stick like you are using now.
So 250 NM with a generic set is quite good, maybe you can add 50-100 NM additionally when using better equipment but that would be it. After 350 NM your limitation would be the curve of our planet.
I’m having trouble getting HeyWhatsThat to work properly this afternoon, but I find it unlikely that your true maximum distance is 440 miles (about the distance between Frankfurt and Monaco). At least, not at normal altitudes. My guess is that either you’ve entered an incorrect height for your antenna, or the data from HeyWhatsThat at your site is incorrect. It’s either that, or you’ve set your Up In The Air to 30,000 meters instead of 30,000 feet.
Thanks for the hint. I actually got my units mixed up. Had the correct altitude for my antenna but wasn’t aware that the units for the yellow and blue lines change accordingly as well.
With the correct units it does look pretty much like what I’m seeing right now.
Therefor, I can skip buying hardware, right?
I did notice though that while my maximum range is around 250nm, it averages around 78nm.
Is this due to weather and/or can this be improved by better hardware?
Skip? Yes. You can always skip spending more money. But a higher-gain antenna will help improve reception at long distances.
As for your average distance–someone correct me here if I’m wrong–but I believe that’s the average distance of positions decoded by your system. If you live near a major airport (like Frankfurt) that would usually reduce your average distance.
Is it possible to buy (or make) a “compound” antenna which has a part that has high gain towards the horizon (such as a coco with many segments) plus a part which has reasonable gain above the horizon, and for these parts to work together to provide a single RF feed?
Probably possible not in a single antenna, or even two antennas in a single SDR. Each antenna is going to have a particular amount of gain associated with its design, so you’ll get almost the same gain off the antenna no matter the range or position of the aircraft (it’s not quite “universal”), plus whatever your set gain amount is in whatever is programming your SDR. Two antennas would also be difficult to make work together as the likelihood is you’ll get them interfering with each other instead of working together.
However, you can have two separate SDRs with different serial numbers (or even on separate RPis), and have a high-gain “distance” antenna on one and a low-gain “local” antenna on the other.
