AirNav Systems Forum

AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: jetset on June 09, 2013, 06:18:52 PM

Title: Reception wall?
Post by: jetset on June 09, 2013, 06:18:52 PM

Can anyone give any thoughts as to what could cause this apparent brick wall reception limitation in the North East of my polar diagram?
(http://i.imgur.com/DD0XzT2.jpg)

I'm not aware of any obvious obstructions in that direction.

Title: Re: Reception wall?
Post by: ACW367 on June 09, 2013, 08:00:22 PM

The brick wall is the airway linking the Northeast UK with Amsterdam.  Because of the north sea military ranges there is very little route variation by the ADS-B airliners.  I'm guessing you don't have the range for the next airway further out over the north sea.

Title: Re: Reception wall?
Post by: jetset on June 09, 2013, 08:28:54 PM

Thanks but I don't think that's the problem.
Here's a screenshot of Flightradar
(http://i.imgur.com/Kdm18ls.jpg)

Here's my box showing 2 planes heading for the brick wall which get time-outs when reaching it. 

(http://i.imgur.com/IbmSia8.jpg)

Title: Re: Reception wall?
Post by: Runway 31 on June 10, 2013, 07:37:04 AM

Stephen

I would suggest that you are at the limit of your range as you are around 175 miles out there so I wouldnt be concerned as looking at the polar diagram it is no less then in any other direction apart from a few spikes.  The north east is not any different than the western side in fact it is a bit better being constant with the 179nm cirlce whereas the other side is consitantly less than the 179 nm line.  The east, south and south west are showing a lot less range than the north east.

A 350 mile radius is not to be sniffed at and I wouldnt worry about it.

Alan

Title: Re: Reception wall?
Post by: bratters on June 10, 2013, 08:10:03 AM

I think the problem is probably topographical.

Bear in mind 2 points -  line of sight and aircraft altitude.  Like you I'm fortunate in having a 360 view but I have directions where reception is down. One is to the flat east which was a surprise but can be explained by a chimney being sufficiently close to blot out a surprisingly large arc.

Another is a wall is to the north - this is caused by intervening hills/mountains - requiring an altitude of 35000 plus  on the extreme edge of my diagram for a signal to be obtained.

Try a few doodles on piece of paper involving ramps and rising straight lines and you might be able to find the blocks on a map.

Title: Re: Reception wall?
Post by: RodBearden on June 10, 2013, 11:13:37 AM

To aid in your experimentation try the Heywhatsthat profiler Up In The Air feature and try different antenna heights:
http://www.airnavsystems.com/forum/index.php?topic=3335.msg31610#msg31610 (http://www.airnavsystems.com/forum/index.php?topic=3335.msg31610#msg31610)

Rod