ADS-B Long Range Plots

[Grahame Hutchison]

When I had a look at the PlanePlotter tracks sourced from my ADS-B receiver today, there were several good tracks out past 300nm to the northeast.

The track through DRUMO (29° 30' 19S 157° 36' 41E) was by Emirates B777-31HER A6-ECI on route from Auckland to Brisbane, and I just happened to be watching while it was displayed. The Start Position was S29 48.6 E158 11.1 and End Position S29 40.3 E157 55.3, some 421.1nm and 414.9nm from my receiver respectively.

If I can track down the other five or six plots outside the 300nm, I will post the details.

While I was writing this post, I had another look at RadarBox and there was a plot out at 435nm to the east. There must be something in the air this evening.

SQLite view of the A6-ECI record in the database.
http://www.16right.com/MessageBoard/SQLite 20120822.jpg

PlanePlotter screenshot of today's plots.
http://www.16right.com/MessageBoard/Planeplotter 20120822.jpg

[Grahame Hutchison]

Another plot was PBN154 Fiji-Sydney operated by ZK-PBM out at 431.3nm.
http://www.16right.com/MessageBoard/SQLite 20120822-2.jpg


Next up was ZK-OJN out at 360nm.
http://www.16right.com/MessageBoard/SQLite 20120822-3.jpg


ZK-PBG from Brisbane to Dunedin out at 299.9nm.
http://www.16right.com/MessageBoard/SQLite 20120822-4.jpg


N171UA from San Francisco out at 369.4nm right through to 28.2nm and 2975ft
http://www.16right.com/MessageBoard/SQLite 20120822-5.jpg


ZK-ZQA from Auckland to Brisbane out at 432.8nm.
http://www.16right.com/MessageBoard/SQLite 20120822-6.jpg

Just had another look and there is another flight tracking Northwest-Southeast out at 444nm.

So far today there have been 15 flights received out past 300nm - just love these conditions.

[Mike Scott]

The enhanced reception distances you are seeing is the result of tropospheric ducting...it happens at all RF frequencies and results in varying conditions for both transmission and reception of rf. When you mentioned "something in the air" you were in fact right !!!

We have the same thing happen in ham radio with our repeater systems (Vhf and UHF) where all of a sudden we start hearing stations a long way away and getting interference from stations on the same freq that we don't normally hear....good example is all of a sudden somebody on one of the high hills or mountains around here (PHNL) can work somebody in California direct with a handheld radio....a distance of some 2300 miles...it might only happen for a few minutes...might last for an hour.

The frequency that ADS B operates (1GHZ) is less prone than some of the lower freqs but it does still happen resulting in reception over much larger distances.....then you look again 5 or 10 mins later and its gone....maybe even a few minutes later.... Tends to happen more at certain times of the year. Also happens with TV signals if you have an off air antenna rather than cable...all of a sudden you start seeing stations from a long way away that normally you don't see.

http://en.wikipedia.org/wiki/Tropospheric_ducting#Tropospheric_ducting

This is a segment from the page below provided by a radio amateur working with ADS B propagation etc


"In the spirit of Amateur Radio (well, one of the spirits) I decided I needed a bigger antenna, with more gain. I constructed a 16-element coaxial Co-linear (~12-dBd?), and mounted it 3 metres above the top of my 144 MHz array – about 14.5 metres above ground level. After a short (3.5 metre) run of SCF12-50 heliax, a VK5EME kit dual-stage Pre-amplifier (MGF1302 followed by an ERA-1) provides a boost before the signal hits the run of LDF4-50 to the receiver. Maximum range observed reliably so far is 225 nm (416.7km), with aircraft flying at high altitude (38,000-40,000 feet), though instances of greater distance have been observed as we enter late spring and come under the influence of tropospheric “ducting”.
I decided that wasn’t enough, so I built a 28-element T-boom Yagi. This has a calculated gain of 16.7-dBd. Admittedly I lose the omni-directionality of the co-linear, but I was more interested in maximizing my forward view".


http://www.qsl.net/vk3bjm/ads-b.htm

Some good charts directly related to ADS B here
http://my.pinkfroot.com/forum/topics/your-longest-range-direct-adsb

Sorry to be so Geeky :cool: tried to keep the explanation short but its quite a complicated and involved topic.

Regards

MS

[Grahame Hutchison]

Thanks for the info and link Mike, very interesting. There are definitely days when reception is extended significantly.

A few more good plots today out to the northeast, and a host of dot plots directly to the east, which I believe is the
suspect LAN CC-CQC. The most distant LAN plot was out at 535nm.

http://www.16right.com/MessageBoard/Planeplotter 20120823.jpg

ZK-OJG may have operated Christchurch-Brisbane (after an earlier Melbourne-Christchurch sector) at a range of 496.1nm (to be confirm).
ZK-OKA operating Brisbane-Auckland at a range of 436.2nm.
http://www.16right.com/MessageBoard/SQLite 20120823-7.jpg


9V-SVE operating Auckland-Singapore at a range of 444.2nm
http://www.16right.com/MessageBoard/SQLite 20120823-8.jpg

[Michael Dawson]

Grahame,

You would have got the Dunedin flight as Misly is one of it's waypoints before hitting BNE area. Having done that flight a few weeks ago, this and the Queenstown flight are from quite southerly reaches. The Dunedin flight tracks overhead Queenstown in both directions.

Cheers

Michael

[Henning S]

Yesterday in the evening (around 11pm) I had an awesome reception of AIS messages. I thought that the marine authority was testing a new AIS repeater or something like that. Never had so many ships on my screen before. But maybe it was also related to this In-The-Air thing.
Now the reception is normal again... unfortunately...

[Grahame Hutchison]

Tropospheric Ducting http://en.wikipedia.org/wiki/Troposp...pheric_ducting (http://en.wikipedia.org/wiki/Tropospheric_ducting#Tropospheric_ducting)

Tropospheric ducting is a type of radio propagation that tends to happen during periods of stable, anticyclonic weather. In this propagation method, when the signal encounters a rise in temperature in the atmosphere instead of the normal decrease (known as a temperature inversion), the higher refractive index (http://en.wikipedia.org/wiki/Refractive_index) of the atmosphere there will cause the signal to be bent.


I guess the warm northwesterly winds over the last two days might be part of the reason.

Thanks Michael, on some of the flights there is just not quite enough information to identify the Aircraft and Flight No. The last ACARS report for ZK-OJG had it going into Christchurch. ZK-PBG from Brisbane to Dunedin via MISLY was a nice lateral plot at 300nm.

[Grahame Hutchison]

Looks like there is something in the air again, good plots out between NATLI and DRUMO ...

Emirates Auckland-Brisbane flight UAE435 operated by A6-ECI, out at 342nm (633km).

http://www.16right.com/MessageBoard/Planeplotter%2020120829.jpg

[Grahame Hutchison]

Still some good ADS-B plots this morning, maybe the warm air from Queensland moving down towards New Zealand.

[Grahame Hutchison]

The long range reception definitely follows the warm westerly/northwesterly winds. Reception out to the northeast increased to just on 900km.

http://www.16right.com/MessageBoard/Planeplotter 20120905.jpg

[Clinton Radloff]

Grahame,
i also do long distance reception. been doing tv and radio for 5 years and only just started on ACARS during August. i get my GNS in under 24hrs from Melbourne so ill have a GS up at my QTH in Booval wednesday. with a test near YBBN later on. yey. ill post some screenshots that night to show all. or you can see my ADS-B book of records when it starts from Wedneday. cheers Clinton

[Grahame Hutchison]

Conditions were good again today for long range ADS-B reception. The plot out to the northeast starts at 550nm (1018km),
that's further than Bundaberg from Sydney, just amazing.
http://www.16right.com/MessageBoard/Planeplotter%2020120910.jpg

[Clinton Radloff]

ill see how i go near YBBN tomorrow

[Clinton Radloff]

im at Booval and i tracking at 950km i think it works....? adsbscope 2.6 with GNS 5890 on my back patio at my QTH in Booval
http://cjradloff762.webs.com/8.jpg
http://cjradloff762.webs.com/9.jpg

[Clinton Radloff]

the hepburn chart shows inland tracks
http://cjradloff762.webs.com/aus006.jpg