I purchased this model the other day and took it on a short trip to try it out. The MRX works by detecting your transponder's Mode C output. It then detects Mode C replies from other such equipped aircraft and monitors the closest "threat". So... if an aircraft is not equipped with a mode C transponder, the unit wont detect that particular "threat aircraft".
Unfortunately, while testing, the short trip i was on went through an area of relatively low traffic density.
I had set the unit to 5.0NM range and +/-5,000 ft altitude... the whole way over it showed "--.- nm ---ft" meaning "no traffic"
once we were within about 3 miles of the destination airport a Robinson R44 helicopter departed the ramp and headed Northwest (toward us) at about 1500 ft MSL.
our altitude was 2500ft MSL.
within a few seconds after the chopper became airborne the little unit beeped twice, the indication that a new aircraft had been detected (4 beeps is an alert for close proximity).
the blank screen was replaced with "2.0NM -011FT" indicating that we had traffic 2 miles away, 1,100 ft below us.
we estimated the distance visually to be about 1.5 - 2 miles. so the range was accurate, and the helicopter announced his intent to depart at 1500 MSL while we remained at 2500 MSL this meant that there was about 1,000 foot vertical separation. so the little unit was about as correct as you would expect.
eventually the distance counted up to 5.0NM and went blank as the helicopter went further away from us.
on final approach, a Cardinal RG sat waiting for takeoff... the unit picked him up and eventually issued an "ALERT!" as we closed within 1NM and 500 ft vertical separation.
as we neared the ground for landing, signal quality became nil and the unit stopped announcing traffic.
On the return leg, same story, no traffic was encountered except for one aircraft that came within "1.5NM +029" (1.5 miles and 2900 ft above) which placed them well above the overcast cloud layer so - we never saw them to make a visual confirmation of the unit's indication.
As we neared our home airport, a king air departed toward us, we had no visual on the aircraft and the unit did not indicate any traffic.
I can only assume that the King air - being operated by a local "cowboy type" aircraft salesman - failed to activate his transponder before takeoff. thereby rendering the MRX unit incapable of locating the king air.
I look forward to further testing when the weather clears in a day or two.
for now my verdict is mostly positive.
we had 1 aircraft definitively tagged up on the MRX... and the range and altitude differential was pretty darned accurate in my opinion
we had a 2nd aircraft that was detected, and the unit alerted us to close proximity, but as we neared the ground - understandably the mode c reply of the threat aircraft would be less and less pronounced so... i cant blame the unit for "trailing off" of this contact.
We had a 3rd aircraft that the unit detected well above us, but because of the overcast, we couldnt visually verify the traffic's proximity in comparison with the LED indication on the screen.
Finally, we had a 4th aircraft that was acquired and avoided visually, but that the MRX did not detect - Possibly... in fact very probably because the aircraft did not have his transponder on.
I wont give it two thumbs way up just yet... but im on the way to giving the MRX my approval
