ComputerDoc wrote:Hi Ed,
I'm pretty ignorant about ADS-B recievers (so take my comments below with a grain of salt) but like others here keeping my eyes open for price dropping.
You wrote, in part -- "The GNS 5870 is traffic only.. no weather, as well as having other limitations. It is only a single band (1090 MHz) receiver, which is intended for aircraft flying above 18,000 ft. Aircraft below 18,000 are equipped with 978 MHz.. In terminal radar areas, all traffic is displayed, but outside (about 77nm from the radar antenna) traffic reports depend on someone in your immediate area with an ADS-B transceiver to "wake up" the broadcast station and transmit traffic."
My understanding is that the need for someone else's radar interrogation to "wake up" the transponderbroadcast from nearby aircraft before your low end ADS-B receiver can detect it is not a show stopper. From my understanding of the exchanges on forums of users of the low end ADS-B recievers there is far more airspace where aircraft's transponder are being interrogated by radar (whether by ATC or other sources) than not. The comments are along the lines of "unless you're out in the boonies in Alaska....".
Point is I'd rather be altered to nearby traffic SOMEtimes than never -- even if it was only, say, 60% of the time. No one in their right mind should be DEPENDING on an inexpensive ADSB reciever to warn them of traffic. It's just, so to speak, one other pair of ears/eye. If a device like that alerts me to ANY traffice I might otherwise be unawer of it's worth the $300. IIRR a number of users of the lower end passive receive units already have posted their war stories about the day the unit already paid for itself well by alerting to unseen traffic. In short, I'm trying to make a case for supporting low cost ADS-B receivers even if they're imperfect and doing so sooner rather than later. How am I doing at that? 
Anyway -- How about a list of what ADS-B receivers ARE supported by iFly? And which are under consideration? And which you consider it unlikely you'll support in the forseeable future, so none of us rush out and buy one of the later?
Alex
Alex -
Just my 2 cents but having used both ADS-B (Skyradar on iFly) and a Zaon MRX, the Zaon is by far a MUCH, MUCH better traffic awareness device. I have no affiliation with them. I purchased an MRX after a very close call early in my training and later used it in conjunction with the traffic on my Garmin 530 for many months of comparison.
Quite simply, it is amazing. While it lacks the ability to tell you exactly where the traffic is, you know it's there (so long as they have a working transponder that ATC can ping). It tells you how far away, closing or retreating, higher or lower, climbing or decending. It does this for ALL TRAFFIC within the notification envelope. While testing against the 530 it was obvious that this unit works very well. No doubt the traffic on the 530 is better due to the visual display but there was hardly a time that the Zaon didn't warn of traffic. Sometimes it even alerted before the 530.
The same cannot be said of ADS-B receivers. Other than weather I think they are virtually worthless. I have been testing for months in the NY metro area and have seen 2 warnings. Out of the hundreds of reports from Garmin, just 2 from the Skyradar. Very disappointing. If you are mostly interested in ADS-B traffic you need to get a transceiver and then perhaps the traffic will be of use.
Had I known then what I know now I may have waited for transceivers to become available at realistic prices before buying the Skyradar. I don't look at it as a total waste.....the weather is very useful and seems to be working well. With traffic on the 530 (and Zaon as a backup if needed) and weather from the iFly / Skyradar, I've got my bases covered and flying is all the more pleasurable with the enhanced awareness these devices bring.
Dave
PS - anyone know why they don't broadcast traffic at all times on ADS-B? If ATC has the info why not just send it like the info received from TCAS? I realize transmitting ADS-B has various advantages but why limit the info to only those that are transmitting? Why not keep the recievers "awake" to receive at all times? Even if the info is coming from a transponder I would think it easy for ATC to transmit this info on the ADS-B frequency for all to see.