Graham wrote:
I've no TCAS experience, but I often get traffic called by a radar unit which I 'should' be able to see but cannot for the life of me. I guess our eyes really are awful.
I often get traffic called out by ATC as much as 10 NM away. There is no way I can make out a GA aircraft during the daytime that is more than 2 miles away, even if I know about it. Spotting an airliner isn't difficult at 4 or 5 miles. If I have done my math correctly, a typical GA aircraft wing span only represents a .2 degree arc at 2 SM distance and straight on the fuselage only .02 degree.
Peter,
The use of the mutual buss is supposed to be bi-directional with other devices on the buss, any one of which is permitted to assert the signal. They are required to sample the signal for inactive prior to asserting it. I believe there is an ARINC specification for it.
Some googling on that ARINC suppression bus..
This talks about it loosely but says little.
I suspect this terminology actually applies to suppressing transponder transmissions in a TCAS-II environment (where you get RAs) rather than to the operation of that wire which happens to have a similar name.
But who knows...
They are required to sample the signal for inactive prior to asserting it
That just sounds inherently dodgy - a bit like Ethernet 
Ethernet works because the transmitter backs off for a "random" time and then tries again.
The factory built-in traffic equipment in my aircraft (Avidyne TAS600 series) has its pluses and minuses. I am assuming the minuses have nothing to do with a faulty installation..
It can give me false readings in terms of orientation and distance of other traffic in the 'medium' range, say from 1-5 miles. However, when the threat becomes real, the system is spot on, with a distinct voice shouting out : 'traffic, x o clock, less than one mile'. The Garmin has given me a choice to set a male or female voice, so it is of course not male.. No no Jude, don't get me wrong! It is because I do not take other men seriously!
The issue of course is that not all aircraft carry (working) transponders so I spend most of my time looking out. Better views anyway.. And use an odd altitude, like 875.5 feet. I also like the feeling that most traffic is higher than me, they really stand out against the sky. But in a single-engine my trade-off is different: a bit more air between my feet and a suitable landing spot feels better.
Luckily at my (uncontrolled) airfield we all do a great job on position reporting.
And use an odd altitude, like 875.5 feet
You are able to fly 875.5 feet? Pray, tell - how ???
Ah, well, actually 875.48 but I rounded it (John Wayne voice)
You are able to fly 875.5 feet? Pray, tell - how ???
To encode altitude to 1/2 ft you would need about 16 Gray code bits, so with a customised encoding altimeter and a really high performance autopilot, no problem.
Lenthamen wrote:
I have a PCAS (the Zaon MRX) and it's a cheap solution for traffic avoidance.
How do you find the MRX unit? The owner of the plane I am buying is throwing in a XRX unit...
How do you find the MRX unit? The owner of the plane I am buying is throwing in a XRX unit...
I use it when flying VFR. Sometimes it happen to me that the unit is not bound properly to the aircraft transponder (i.e. the unit shows a different transponder code as what I have on). Another problem I sometimes face is that is giving alerts because it sees my own transponder signal as a thread. This "ghost" traffic is displayed at a 0.5NM range, same altitude. That looks really scary ;-)
Nowadays 90% of my flying is IFR on Airways. I do not use the Zaon MRX when under radar control... If the Zaon MRX would work fine 100% of the time, I would probably have it switched on also when IFR ;-) But it isn't that reliable and the false alarms are only distracting...
Thanks....The MRX doesn't sound that great then..... The XRX unit gives azimuth (at 45deg increments) but can be connected to a Garmin Aera to display pseudo ADS-B TIS...in that case the azimuth resolution is more like 22deg apparently...and uses the standard TAS symbology....so I am probably going to shell out the £140+ for a cable to link the two... I'll let you know how it goes...
