>> Another big influence is the antenna pattern of the antenna on the >> aircraft. Fuselage, wing and empennage are the blocking structures of >> course. If you want I can have a look and get you some "typical" data >> for "structure blocked signal loss". >> >> A lot of aircraft have a seperate GS antenna in the cockpit because: >> 1. antenna cable short (NAV unit is in cockpit usually) >> 2. excellent view of the runway (...) >> > Thanks for the information. Of course, this would depend on the antenna > position on the fuselage. Would it be placed underneath the aircraft? Perhaps > the antenna gain might be increased in some situations by the fuselage acting > as a huge reflector? Since there can be many specific situations, antenna gain > will be configurable on a case by case basis. > I will spend more time doing research, but would definetly appreciate if you > know a reliable source for this type of information online. As I said earlier, > I think it could be possible to add antenna radiation patterns, at least in a > simplified way. > > Thinking of most GA and business aviation aircraft I know the NAV antenna (VOR/LOC/GS) is always located on the vertical tail, just below the horizontal tail with a cross or t-tail and on top of the vert. tail with a low hor. tail. These are usually two antennas, one on each side of the structure. They are on the vertical tail because NAV signals are polarized horizontally and thus the antenna must be installed that way (unlike COM which is polarized vertically and you will find these antennas standing up or down.) As I mentioned before, there is sometimes a separate GS antenna in the cockpit or on the fuselage directly above it. It looks like a small V about 30cm wide. These are all passive antennas. See http://www.cobham.com/about-cobham/aerospace-and-security/about-us/antenna-systems/fullerton/products/vorlocgs.aspx for instance
Gain increase by reflection on aircraft is not something I am aware of. I know that for COM 1/4 lambda antennas (or 1/4 lambda antennas in general) you need a good ground plane to get the VSWR down to an acceptable level. Regards Eric ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
