On 11/28/2011 06:14 PM, Adrian Musceac wrote: > On Monday, November 28, 2011 18:31:42 Eric van den Berg wrote: > >> For GA (what I have handy right now): >> The good old Garmin 400 series: VOR/LOC:-103.5dBm, GS:-87dBm >> Avidyne (EntegraII): VOR: 5uV, LOC and GS: 10uV >> >> www.repeater-builder.com/measuring-*sensitivity*/*dbm*2uv.pdf >> /for conversion table!/ >> >> The Avidyne is TSO minimums if I remember correctly. Their units tend to >> depend on GPS (and thus do not care much for radio navigation). >> >> Airline stuff goes down to like 0.5uV (so much more sensitive and >> expensive). They can receive a VOR signal at FL300 at quasi-optical range! >> >> > Thanks, that is useful data! From what I could gather from different sources > on the internet, typical VOR ground equipment operates with around 100-200 W > ERP, am I correct? > > That I do not know. But I do know there are long-range and short-range VOR-s with significantly different output levels. Not sure how to determine the difference easily. For NDB-s it is more easy. The short range ones are on or near the threshold and at the FAP typically. > >> Antenna cable losses have to be added for in airplane performance (and >> they are usually significant). >> > I will make the antenna gain configurable for each station/aircraft, so any > cable losses can be added into the system that way. I think that losses might > not be very high in the VHF airband unless the aircraft uses very crappy coax > or a significant length, but that might change for GS frequencies in the 300 > MHz range, of course. > > Well the standard in GA aircraft is RG400. Which is pretty crappy (approx. 12.5dB per 100ft). If you take a typical GA aircraft 10m in length, NAV unit in cockpit, VOR/LOC/GS antenna on the vertical tail. Antenna cable may be 15m (50ft) + one bulkhead connector (another 1.5dB?) = 7.5 dB signal loss (=38% signal strength left). Bigger aircraft have corresponding longer antenna cables and a pressure cabins (so more possible bulkhead feed-throughs: these connectors are real signal killers) which might use RG213 or even RG393.
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 (...) Eric > Cheers, > Adrian > > ------------------------------------------------------------------------------ > 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 > > > ------------------------------------------------------------------------------ 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
