Radio, Node
Stargazer
It follows a directional ADS-B receiver, scores it against adsb.fi, and estimates the antenna aperture and range pattern. Every decoded position is saved to disk and can be replayed.
- 340.2 km
- The farthest aircraft heard so far.
- 198,782
- Position fixes across the two antenna profiles shown here.
- 360
- Bearings scored separately.
The measured pattern
Reach by bearing
Real data from the receiver: the farthest aircraft heard on each of 360 bearings, for two antenna profiles. North is up. Move over the chart to read a bearing.
- Bearing
- 0
- Filled pattern
- 0
- Orange line
- 0
Scoring an antenna
An antenna that faces one way hears more in that direction, and Stargazer measures how much.
It polls adsb.fi every five seconds and counts, per degree of bearing, how often an aircraft that the public network sees is also heard locally. Only aircraft beyond 50 km and above the radio horizon count, because nearer ones say nothing about aperture.
Nothing is sent to any aggregator. Feeding adsb.fi from this receiver would make every aircraft the antenna hears look like a hit and spoil the score.
How far can it see
Radio horizon
The distance at which the curve of the earth hides an aircraft from an antenna, with the usual 4/3 earth radius correction.
- Line of sight
- 0
- In nautical miles
- 0
- Antenna alone
- 0
What it keeps
- ReplayEvery position is stored as one row in a daily file and can be played back.
- RecordsPer-degree range, reach, and the totals of sees and misses against adsb.fi.
- AircraftCallsign, registration and type per aircraft, with photos from Planespotters and the photographer credited.
- Running itNode 22 and nothing else. The receiver position is worked out from the feed.