What is the Maximum Range I can Get?

[lignumaqua]

Lots of questions here! Both the range ring and the heatmap start up include the recent history that the web page downloads from dump1090. This is deliberate. This same history means that we are able to display a track on an aircraft immediately you open the page.

In contrast, ‘Reset range ring’ starts completely from scratch, discarding all the history. I haven’t provided the same ‘Full reset’ option for heatmap, but it would be simple to do so if requested.

This all makes sense to me, both the heatmap and the range ring need time to build up and including recent history means that you get a small jump start on that process.

As to the range ring altitude. At the moment it looks for flights at any height but, I agree with you, it might be interesting to allow display of range rings restricted to certain altitudes. For example, a ring showing maximum range for flights at 10,000 ft or below. I’ll look at adding that!

[TomMuc]

@lignumaqua

… As to the range ring altitude. At the moment it looks for flights at any height but, I agree with you, it might be interesting to allow display of range rings restricted to certain altitudes. For example, a ring showing maximum range for flights at 10,000 ft or below. I’ll look at adding that!

you find this feature in vrs too - and maybe is a useful role-model …

[sesom]

I did a quick & dirty implementation for 30000, 33000, 36000 and >36000 feet, but as at this time (22:20 local time) most aircrafts are at high altitudes on their way to Middle and Far East, it will take some time to show 4 full range polygons. But this should be done properly (=configurable).

http://i.imgur.com/8BdyXkZt.png
Click for fullsize image

PS: Red aircrafts in the table have no data in flight-database, blue aircrafts are military aircrafts.

[sjacket99]

@sesom

@abcd567

Which software you used to record the video?

I am running Ubuntu. It’s just a bash script taking screenshots of the browser window:

#!/bin/bash

while :
do
        import -window 0x4e025e6 screenshot_`date +"%Y-%m-%d_%H-%M-%S"`.png
        sleep 10
done

0x4e025e6 is the id of my browser window, can be found with “xwininfo -display :0”

The mp4 this i made with this command:

ffmpeg -f image2 -r 10 -pattern_type glob -i '*.png' output.mp4

I use this command on my MAC. Just replace the TimeLapse with where ever you want to save the screenshots.

while  1 ];do vardate=$(date +%d\-%m\-%Y\_%H.%M.%S); screencapture -t jpg -x ~/Desktop/TimeLapse/$vardate.jpg; sleep 10; done

[triggers]

I have an anomaly with my range rings from Heywhatsthat. Note where the rings are with respect to Dublin. Anyone else with this problem?

Here are the rings from gmap.html

https://img.cloud.photobox.com/304776308a69373eaae3c42f2b7a3e4444dc7f360e7c279b7976045492917116d4c6ff1c.jpg

Here are the same rings on heywhatsthat

https://img.cloud.photobox.com/241205846a423a147475eabae74a7e48503483b68d6ea856c3a811db2be82205bbb43bf9.jpg

[lignumaqua]

@triggers

I have an anomaly with my range rings from Heywhatsthat. Note where the rings are with respect to Dublin. Anyone else with this problem?

Here are the rings from gmap.html

https://img.cloud.photobox.com/304776308a69373eaae3c42f2b7a3e4444dc7f360e7c279b7976045492917116d4c6ff1c.jpg

Here are the same rings on heywhatsthat

https://img.cloud.photobox.com/241205846a423a147475eabae74a7e48503483b68d6ea856c3a811db2be82205bbb43bf9.jpg

If you are using the recommended refractive index then you’d expect to see a little further with the ADS-B signal than with visible light. It bends around the earth slightly due to refraction in the atmosphere.

[toverfield]

Does the received range ring also expand during the MLAT zombie period? I’m referring to the FA fed MLAT traffic from your cooperative feed partners after yours has lost the signal.

[lignumaqua]

@toverfield

Does the received range ring also expand during the MLAT zombie period? I’m referring to the FA fed MLAT traffic from your cooperative feed partners after yours has lost the signal.

It only expands the range if there is current valid received data, however that data can be from MLAT. I.e. if the plane appears with a solid marker on the map. I’m not 100% sure if that meets your criterion or not. I wasn’t aware of ‘zombie’ data.

obj - if you are reading this - how would such data be distinguished from the json file?

[obj]

It is not distinguishable.

[lignumaqua]

Thanks obj. Toverfield - I guess the only way to be sure would be not to include any MLAT data at all. That would remove the zombies, but, in the US at least,would mean that the range ring would take a lot longer to produce. Let me experiment with that.

[triggers]

@lignumaqua

If you are using the recommended refractive index then you’d expect to see a little further with the ADS-B signal than with visible light. It bends around the earth slightly due to refraction in the atmosphere.

@abcd567

@obj
The default value of refraction on heywhatsthat site is 0.14, but you have specified refraction=0.25. I am not sure, but feel this is due to slight difference in propagation parameters of Light waves & Micro waves, and will cover for difference between optical and radio horizons (For microwaves, the radio horizon is farther than optical horizon by say 50 nautical miles or so).

Many thanks for the explanation. I did read about this further up the thread but I didn’t put 2 and 2 together.

[lignumaqua]

Some updates now on Github at github.com/lignumaqua/dump1090 :

1. Added toggle for heywhatsthat predicted range polygons

2. Added option to produce any number of range polygons at any
   specified altitudes. New config.js option to set range altitudes and
   colors for polygons.

// Set Altitudes and Colors for Range Rings
// RangeAltitude is an array of altitudes in feet
// Use 99999 for range at any altitude
// RangeColor is a corresponding array containing the color values of the rings
RangeAltitude  = new Array(99999,30000,10000);
RangeColor     = new Array('#008000','#000080','#800000');

3. config.js option to use MLAT data or not in range polygons. (Without MLAT will be slower, in the US at least, to build the polys, but will avoid any zombie readings)

// Allow use of MLAT data for the range poly
UseMlatDataForRange = true;

Files updated this rev:
gmap.html
planeObject.js
script.js

You need to make the additions to config.js manually, do NOT pull the version on Github or you will overwrite your personal settings. Add the following to the end of the file:

// Set Altitudes and Colors for Range Rings
// RangeAltitude is an array of altitudes in feet
// Use 99999 for range at any altitude
// RangeColor is a corresponding array containing the color values of the rings
RangeAltitude  = new Array(99999,30000,10000);
RangeColor     = new Array('#008000','#000080','#800000');

// Allow use of MLAT data for the range poly
UseMlatDataForRange = true;

[sesom]

Thanks for sharing the code. Just one minor error:

In script.js

        if (localStorage'ShowPredictedRange']) {
            ShowRange = JSON.parse(localStorage'ShowPredictedRange']);
        }

should be

        if (localStorage'ShowPredictedRange']) {
            ShowPredictedRange = JSON.parse(localStorage'ShowPredictedRange']);
        }

at later on when the value is stored there is a p insted of P in the localstorage-value:

    localStorage'ShowPredictedRange'] = JSON.stringify(ShowPredictedRange);

[mgunther]

@sesom

Thanks for sharing the code. Just one minor error:

In script.js
(…)

I submitted your fixes as a pull request on Github.

[lignumaqua]

@sesom

Thanks for sharing the code. Just one minor error:

In script.js

        if (localStorage'ShowPredictedRange']) {
            ShowRange = JSON.parse(localStorage'ShowPredictedRange']);
        }

should be

        if (localStorage'ShowPredictedRange']) {
            ShowPredictedRange = JSON.parse(localStorage'ShowPredictedRange']);
        }

at later on when the value is stored there is a p insted of P in the localstorage-value:

    localStorage'ShowPredictedRange'] = JSON.stringify(ShowPredictedRange);

Thanks! Copy and paste errors.

[Goldy714]

Hey guys,

I just beat my range record with my home made 8 element co-linear antenna made of RG-6 so I’m pretty chuffed. My new PB is a tad over 350NM.

It has taken a few months of small adjustments one at a time to get this far and now I’m loathe to change it. If only the terrain to the North and West wasn’t so high. My antenna is mounted on my single storey garage with the coax fed to the gear inside.

My setup is:

Antenna → 1.5 metres RG6 coax → PVLA-30 → 9 metres RG6 coax → 12VDC pwr injector (for PVLA-30) → 0.5m RG6 coax → F connect to SMA converter → 950-1180MHz BP filter → SMA to MCX tail → Nooelec USB DVB Rxer → Rapberry Pi B+

Here’s the VRS range map with the rings set at 50Nm intervals…Cheers all. Goldy714 http://flightaware.com/adsb/stats/user/Goldy714

[jonhawkes2030]

Something is off with your rings.
They don’t match the scale.
Also, Coffs to Sydney is about 330SM./500-550km.
The rings suggest it is 450NM.
Lord Howe is 363SM. The rings suggest it is a lot more.

I think the rings are about 50NM apart.

I am lucky to get 100NM but my antennas are either 3ft off the ground outside(next to the house) or 15 feet agl inside the house.

I played putt putt golf in Coffs many years ago. I got a hole in one on the 18th hole. The problem was I was on the 17th hole and had hit it too hard. I had to ask for another ball so I could finish the round. I was only about 13.

[Goldy714]

Yep, you were spot on. Sorry about that, got confused with all the numbers - the rings are at 50Nm (just edited the post).

Ahh, the old putt putt golf near the highway on the North side? I remember that one. The only putt putt golf here now is at the Big Banana I think.

Cheers.

[MikeIsler]

Any thoughts on how to add “Bearing from site” to “Distance from Site” for a specific aircraft? a Bearing/Distance readout would be pretty useful, but I don’t have the chops to create that.

[jonhawkes2030]

I don’t recall which course it was. I don’t think it was the one at the Big Banana.

350NM is pretty much the theoretical limit for a location near sea level.