Really useful aerial line-of-sight aid

[RodBearden]

I’ve come across a new tweak on the HeyWhatsThat website.

For those that don’t know it, HeyWhatsThat is a profiling site and very useful for seeing what hills and valleys are in between two points.

In the Testbed site, the author, Michael Kosowsky, has produced a “visibility cloak” – give it a location and how high you are above sea or ground level, and it will show you what the view will be - in itself a really useful trick.

At my request, he has extended the idea to an “up in the air” feature, where you can specify two altitudes and it will draw a line for each, showing at what distance you should be in direct line of sight of aircraft, taking into account the topography and the curvature of the earth.

It’s fascinating to tie this up with your RadarBox polar diagram, and both of these features could be really handy in deciding, for example, whether an external aerial would be worthwhile, and how high it should be by entering different heights above ground level.

It only takes topography into account – it can’t take into account individual trees or buildings which might get in the way, but it’s a really interesting and potentially useful site – give it a go!

PM me if you would like detailed instructions on how to get it to work. (Hint – switch to satellite view to see the “up in the air” lines clearly)

Main site: http://www.heywhatsthat.com/

Testbed site: http://www.heywhatsthat.com/main-0904.html

Rod

[AirNav Support]

Fantastic site, great find.

[radarspotter10]

great site for line of site from your house.
click on new panorama top right. put in your grid reference and away you go.
love it
from pat

[tarbat]

Great fun.   To give people an idea of the results you can see, here's my results using FL100 (black line) and FL350 (blue line).

[radarspotter10]

hi tarbat.
As as radio ham it gives me line of site for my aerials, also love the way it gives you mountains, everybody should give this a go, its a great piece of software free.
from near my QTH.




from pat

[RodBearden]

I'm glad people are finding it useful.

I've had a couple of requests for instructions, so I've created a Word document on how to do it:

http://www.rbearden.toucansurf.com/HeyWhatsThat Panorama.doc

Hope it helps

Rod

[Johnn]

Many Thanks Rod :)

[Marpleman]

Rod

Many thanks for sharing this find

Just spent a fascinating couple of hours on the site

Makes up for the pants weather stopping the spotting at present

It gives a very good awareness of the RadarBox blind spots when you see the surrounding terrain like this

Rich

[radarspotter10]

Rod

Many thanks for sharing this find

Just spent a fascinating couple of hours on the site

Makes up for the pants weather stopping the spotting at present

It gives a very good awareness of the RadarBox blind spots when you see the surrounding terrain like this

Rich

hi rod
same here great piece of software rod, still playing with it.
from pat

[pjm]

very nice - now all I have to do is work out how to get the "theoretical" range the "HeyWhatsThat" has calculated and what I actually get. They are close to the extremes at some points, but way out at others...

[bratters]

very nice - now all I have to do is work out how to get the "theoretical" range the "HeyWhatsThat" has calculated and what I actually get. They are close to the extremes at some points, but way out at others...

I know exactly what you mean pjm.

Firstly as I have an indoor set-up I can only see one hemisphere at a time so a bit of moving about was necessary to check all round. This also means I have "dead" areas either side of my home because of adjoining buildings.

That apart, the Hey! diagram compares reasonably with my polar diagram.  As you suggest it's good in parts but very optimistic in others.  One quadrant of the Hey! diagram in particular is wrong in suggesting line of sight virtually from Leicester to Belfast and Glasgow, notwithstanding the intervening Peak District and Lake District. Absolutely no way! Tracking NW and N is very limited indeed.

Bit of fun though!

[Fenris]

It's because the web tool knows about the terrain heights, but it doesn't know about the local obstructions such as houses, chimneys etc and it doesn't know about what's growing in the fields, whether the trees have leaves and so on.

Calculating accurate RF coverage maps is seriously hard, and needs a lot more data than just the terrain height database.