What is the Maximum Range I can Get?

INTRODUCTION
The Maximum Range achievable at any location depends on
(1) Curvature of earth
(2) The terrain around that location. Terrain plays a very important role as hills & changes in ground level will restrict maximum range.

This is due to the fact that propagation of radio waves in GHz/Microwave range is line of sight. The range is therefore limited by curvature of earth, and is about 250 nautical miles / 450 km for an ideal condition of perfectly level terrain. Hills & rise in ground levels further restrict maximum range to less than 250 nautical miles / 450 km.

FIND YOUR MAXIMUM POSSIBLE RANGE
In order to determine what maximum possible range you can get at your location, follow the steps below:
(1) Visit the site heywhatsthat.com
(2) Select tab “new panorama”
(3) Enter your latitude and longitude
(4) Enter your elevation (=enter elevation of your antenna)
(5) Enter title
(6) Hit “submit request” button
(7) Wait and view sponsor’s advertisement while panorama is generated
(8) When panorama is generated, scroll down to map, and click “up in the air” tab on top right of map.
(9) **Zoom-out **the map till you see two circular curves in blue & yellow colors, showing maximum distance of aircrafts at 10,000 feet & 30,000 feet elevation.
(10) Below the map you will see text boxes light yellow & light blue with default aircraft heights 10,000 feet & 30,000 feet. Change these to suite your requirements, and press “Enter” button. The two curves will modify to new height figures you have entered.

The layers of air cause refraction of radio waves, and radio line of sight may extend beyond optical line of sight by as much as 50 to 100 nautical miles. Your maximum possible range will therefore be about 50 to 100 nautical miles more than the maximum possible range shown by the curves you got from heywhatsthat.com site.


**To achieve your maximum possible range, your antenna should be installed at a height where it is above trees & houses surrounding it, and can “see” the horizon.
**

.

25 Likes

This “how to” should have a sticky for reference.

A great tool for installation planning since it can predict the reception coverage area at a specific antenna location.

The 35000+ contour correlates closely with my dump_1090 map. I would expect a similar correlation at the lower elevations

To find you latitude and longitude

Use google maps, satellite view.

Zoom in onto your location.

Right click where your antenna is and select “What’s here” - that will give your latitude and longitude in decimal degrees - just what you need!

(PS. Do it on a PC, right clicking on a tablet or phone is the same as left clicking :slight_smile: )

I contacted the owner of the ‘heywhatsthat.com’ site and asked about incorporating the results of his up in the air script directly into dump1090-mut maps. He was extremely helpful and told me of an undocumented API call which he is happy for us to use.

Once you have created a view on his site you can then use the ID of that site in this call:


http://www.heywhatsthat.com/api/upintheair.json?id=myviewid&alts=10000

It will return a JSON variable with the coordinates for the visible polygon at whatever height you request in meters (I’ve asked for 10,000 meters in the example above). As an example, here’s what I get returned for my location at 10,000 meters:


{"refraction":0.25,"rings":{"alt":"10000","points":[32.6099729128549,-97.876768],[32.5901622333547,-97.8276043022589],[32.5673846459684,-97.7793775165884],[32.5655488532864,-97.7307222595661],[32.5863844642117,-97.6801231545666],[32.5947967976855,-97.6298317870926],[32.6139858492118,-97.577642480855],[32.6108792611117,-97.5277710188791],[32.6618229528375,-97.46854839268],[32.6718832866013,-97.414742619004],[32.667236916199,-97.3633611571435],[32.6640859728,-97.3114932008198],[32.6724139533899,-97.2564134608061],[32.6883209188023,-97.1984117962444],[32.711278079929,-97.1370882912527],[32.6997334669719,-97.085524219504],[32.7022761307569,-97.0290093863512],[32.7379290977988,-96.9594011286083],[32.7614361833418,-96.8923034366697],[32.8012092987617,-96.8165141819994],[32.7888400040195,-96.7613377415058],[32.7757616658363,-96.7062890924466],[32.7944433274222,-96.6352669475262],[32.8233999621334,-96.5570081184367],[32.9300910669407,-96.4335874931481],[33.0462957712831,-96.2978267292865],[33.000992495958,-96.2521192427864],[32.9760593673483,-96.1946912976481],[33.0216454089557,-96.090800130452],[32.9942775453606,-96.0330035022767],[32.976128565657,-95.9685979282578],[32.9009131439631,-95.9461154923305],[32.8713842838939,-95.8909724860003],[32.8153975156823,-95.8571101512141],[32.7845411637993,-95.8038373826219],[32.7528870235899,-95.7512497263126],[32.7204455729789,-95.699363773431],[32.6872275373622,-95.6481958269935],[32.6532438851523,-95.5977618965079],[32.6185058232462,-95.5480776927984],[32.5983354115957,-95.4832259107467],[32.5618806119711,-95.4347712868977],[32.524701701086,-95.3871173961451],[32.6172513658613,-95.1889421825222],[32.5763608175978,-95.140260179903],[32.5347436293933,-95.0924755852299],[32.621898401127,-94.8778384652919],[32.5763223251441,-94.8292576499855],[32.6324190021194,-94.6386344165945],[32.5832401579718,-94.5899951029521],[32.6276713482288,-94.4002960677756],[32.5749061316618,-94.3519310715182],[32.5456762935365,-94.2653101145802],[32.4908929668869,-94.2187843805835],[32.4354183449082,-94.1734531026608],[32.3792705342451,-94.1293287449837],[32.3210992622313,-94.0890117667188],[32.2636992692387,-94.0473635377301],[32.2056818638333,-94.006955924262],[32.1470658237839,-93.9677995152791],[31.9995480223953,-94.1257935288164],[31.9427521282225,-94.0908619389264],[31.885439669577,-94.0571440636717],[31.8276289952179,-94.0246483428695],[31.7693385756371,-93.9933827762535],[31.7105869964665,-93.9633549240458],[31.7043918812588,-93.7799030178845],[31.6424398463509,-93.7513969317779],[31.5800688349838,-93.7241996688379],[31.5327801118376,-93.6450930023988],[31.4688278285055,-93.6202549424113],[31.4023546689786,-93.6051265771242],[31.3378217826354,-93.5830155889247],[31.2729664913611,-93.5622531013292],[31.2078091123931,-93.5428427743985],[31.101701063609,-93.7333411539814],[31.0391424189131,-93.7173052534019],[30.9763522910139,-93.7025636993156],[30.9133501691264,-93.6891184715623],[30.8501555680952,-93.6769711364077],[30.7867880222842,-93.6661228494302],[30.7630680995857,-93.2658628729439],[30.6933188970681,-93.2596641384975],[30.6242328676637,-93.244793420535],[30.5542014109277,-93.2425824776252],[30.4843538837352,-93.2380097483372],[30.4147119331317,-93.2241995150438],[30.3446783040539,-93.2151103203326],[30.2744356301004,-93.212989796514],[30.2043901535692,-93.224466866499],[30.1341772283622,-93.2230472647185],[30.0635525036947,-93.2163027075995],[29.9932435746293,-93.2196589412837],[29.924097663556,-93.2384448837089],[29.8531946348673,-93.2353675909833],[29.780870947198,-93.2228539792702],[29.7139028879881,-93.2580724571511],[29.6458338088319,-93.2804615724779],[29.5881574177761,-93.3669916628374],[29.5303166724136,-93.4396710621586],[29.4667221695105,-93.4722472051174],[29.3904286671805,-93.4401289351269],[29.3237874985067,-93.459088007187],[29.2655189278671,-93.5134703614521],[29.2043492137074,-93.5520135444905],[29.1492895425469,-93.6111956036496],[29.0901719300002,-93.6519285896716],[29.0062149277611,-93.6086944997096],[28.956027259458,-93.6783294999947],[28.8930804497676,-93.7057045858548],[28.8123820547657,-93.6830791921383],[28.7321173862997,-93.666592365894],[28.6614827324497,-93.6790560169692],[28.6330748682913,-93.7962789171853],[28.6192343665542,-93.9404236853745],[28.5601634877766,-93.9738553510283],[28.4757963253562,-93.9529821162448],[28.4164836200724,-93.9882692025744],[28.3946614677332,-94.0978525069599],[28.3477083283372,-94.1540481020991],[28.3112286126236,-94.2280497214318],[28.285053022547,-94.3176238047698],[28.2318372700904,-94.3575237574186],[28.2090510411001,-94.447312433906],[28.157928430403,-94.4887934205334],[28.0965276471991,-94.5145912717658],[27.991847496967,-94.4779873847092],[27.8634452549297,-94.4135863442776],[27.7731941786557,-94.4089942597085],[27.7037951227078,-94.435479898286],[27.6599070367323,-94.4959488367183],[27.6061460217448,-94.5436591787904],[27.5471736266161,-94.5854694278778],[27.4747159219384,-94.6125934145953],[27.442407809267,-94.6859127124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It is then fairly straightforward to plot those coordinates as an overlay on the map (the red polygon is the 10,000 ft view, i.e.3048 meters).

He also told me how you can change the refraction value that his script uses to one more suitable for RF. If you enter his site through the URL: heywhatsthat.com/?refraction=1 then, when you create a new view, you are given the option to set the refraction value. He suggests using 0.25 instead of the default 0.14 which is used for visible light.

3 Likes

@lignumaqua:
This is great. Thanks for sharing.
Can you please give detailed step-by-step method of adding the above data / json output to the gmap.html of dump1090/dump1090-mutability? This will greatly help Linux noobs, who will otherwise will not be able to benefit from your valuable effort. Thanks.

1 Like

Thanks! I hard coded mine into script.js.

Warning, this is an ugly way to do it, and will probably make people giggle. :slight_smile:

http://i300.photobucket.com/albums/nn30/adsbjunkmail/Screen%20Shot%202015-11-05%20at%2012.27.19%20PM_zpsfahe4au8.jpg

I converted the list of Lat/Long to a Javascript array and added a function called by script.js

Here’s my one file, 10000.js (most of the lat/long pairs have been remove to make this post smaller:

function drawPoly10000() {
// Define the LatLng coordinates for the polygon’s path.
var triangleCoords =
{lat: 45.6135146602288, lng: -77.6161519},
{lat: 45.6537535024284, lng: -77.5529012740097},
{lat: 45.6943856556383, lng: -77.4874881034763},
{lat: 45.6131185010622, lng: -77.6783436514525}
];

// Construct the polygon.
var tenkTriangle = new google.maps.Polygon({
paths: triangleCoords,
strokeColor: ‘#FF0000’,
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: ‘#FFFFFF’,
fillOpacity: 0.35
});
tenkTriangle.setMap(GoogleMap);
}

Then in script.js I added this right before “if (SiteCircles) {”

drawPoly10000();

Also, add this to gmap.html

Repeat process for other radius polygons if desired.

@wnypoker:

Great! Thanks.
You made life easier for noobs with little knowledge of coding HTML/javascript/Linux.

1 Like

I have been a bit inactive over the last few months but thought I’d spring back in a moment or two … looking at mine (I do live in a bit of a ditch);
I’m lucky to reach what is within ‘Orange line’ and certainly don’t reach the blue at all, I have reached near Edinburgh in the past but not sure what happened. Unfortunately my antenna is only facing North as it’s at the front of my house and I could try placing it in the loft/attic however the USB cable would have to be pretty lengthy for this to attempt it or since my garden got re-done I guess I could attempt to put it outside and have the PI near the door in the kitchen but I don’t want to ruin the door seal.

nice post thanks for sharing


http://www.heywhatsthat.com/api/upintheair.json?id=myviewid&alts=10000

Is anyone able to get the json query to work now?
I just get a “200 OK” response but no data, maybe they have disabled that API function :frowning:

Yes, it’s working fine. I suspect you have used the wrong id to substitute for ‘myviewid’ in the API call. It’s not the name that you give the view, it’s the ID that the website assigns. You can see that on the view page (indicated text here). In my case, even though I called the view ‘lignum14138’ my website assigned ID is ‘MAKIULAL’

Thanks lignumaqua, that was the problem. The call is working fine now.

Looking at what I came up with as well as wnypoker’s screen shot using his instructions and the coordinates from the API the resulting range is WAY off. Looking at the coordinates coming from the API and comparing them to the HeyWhatsThis.com map the API coordinates appear to be off almost as if they were scaled up by 400 percent.

Here is the output for a max range at 10000 feet as displayed on heywhatsthat.com.

https://www.swiftbyte.com/misc/hey-whats-this-max-range.png

Now a plot in Dump1090’s gmap.html using the data for 10000 feet from the API.

https://www.swiftbyte.com/misc/dump1090-wrong-max-range.png

The API uses meters, so you need to request data for 3048 m if you want 10,000 ft. I suspect you asked for 10,000? :smiley:

Now that would make sense!
Will check it out again here shortly.

Works good thanks for pointing out the coordinates are in meters.

That’s a great addition.

Good to see theoretical limits when you think you might be missing out but really it’s actually impossible to get further in a certain direction.

Added 40000 and 10000

edit: Went the full way and added 40k, 30k, 20k and 10k. Maybe a bit cluttered. Should probably change the colours to match the plane altitude colours.

http://i.imgur.com/tCGAB27l.png

I must admit I’m quite surprised at how accurate the heywhatsthat overlays can be

http://i.imgur.com/e7xTpXll.png

http://i.imgur.com/hEODWs2l.png

Well I guess I just appreciate a good hack, but I think this is a great solution! Before I go dig out my “sed and awk” book did you have a quick way to change the json results into your javascript array?

I hadn’t even experimented yet with customizing the dump1090 web page until I read this. Now I have mine auto centering on my location and marking it, pretty cool. I will likely add one or two of these polygons now.

I am curious how did you do airplane colors by altitude?

I used the basic text editing app on my Mac and did a number of Search/Replace operations. I used nano on the Pi to edit the javascript and just copied in my array definition.

Dump1090-mutability version 1.15~dev does this by default.