Mode S signal

[kdt1]

Can any one tell me what is a realistic max range of a Mode S signal under the best of conditions? Airnav advertises RB at 300 nm and Kinetics I think at 250 nm.   

[viking9]

My daily max range with the Beast is 230nm for aircraft over FL300.

Tom

[Anmer]

Best range ever for me was 247.2nm for an aircraft at 37,000ft at a bearing of 46 degrees on 15th April 2007.  Typically I get 230nm.

Once I had shared network data I stopped logging.

[vordme]

Best range for me  257 nm @ FL 360 over Atlantic Ocean

[Tristar500]

Best range for me, in Cheshire at 200ft asl, was 259.7nm at 35800ft on a bearing of 157. I also have 2 other plots which just excede 250nm by a mile or two, one on a bearing of about 15 deg and the other on 260 deg.
'Kit' in use is an SBS1 with a chimney mounted DPD antennae and using SBSplotter to plot range.
Normal range though varies between 190nm & 220nm according to direction.

Ian

[eascensao]

Radar theorical range is 256 NM and this takes in account the planet (curve) shape.
Except in abnormal conditions and due to reflection, maximum range with a SBS-1 or any other receptor shouldn't exceed this value.

E.Ascensão
Air Traffic Controller

[lppt3]

Living on top of a hill, close to Lisbon, Portugal, and with the standard antenna on a 1st floor balcony, I've managed to get a few messages around 300Nm from aircraft over the Atlantic, on a SW heading. But as there is much more traffic on the other side of the house, I don't usually have it there. To the other side of the house, I get messages close to 240Nm on a SE heading.

McB

[G4UMW]

The theoretical max range depends on a number of factors including the heights of the transmitter and receiver antennas.

For anyone interested (or unable to sleep) the theoretical max range can be calculated from the formula:

D=1.33(SQRT(2Hr) + SQRT(2Ht))

where D is range in miles, Hr is Receive antenna elevation in feet and Ht is Transmit antenna elevation in feet.

[OH7HJ]

My daily max range with the Beast is 230nm for aircraft over FL300.

Tom

Living in thick northern forests and listening with a 4x4-el yagi aerial on a 4 dB coax mounted below treetop level my Beast reaches daily max of about 140 nm, of course depending on weather.

230 nm ADS-B max reception range is something I am only dreaming about. What are you receiving conditions like aerial height and surroundings?

Radar theorical range is 256 NM and this takes in account the planet (curve) shape.
Except in abnormal conditions and due to reflection, maximum range with a SBS-1 or any other receptor shouldn't exceed this value.

E.Ascensão
Air Traffic Controller

Yes, the theoretical radio horizon of about 250 nm or 420 ... 460 km is the reception range of FL300+ planes with my 50 MHz aircraft scatter experiments, too.

However, the 1090 MHz wide band mode-S is a lot tougher job. It requires almost a line-of-sight clearance to aircraft. Need have either completely clear unobstacled surrounding like sea or to get the ADS-B receiving aerial high above obstacles.


- Juha -