So here we are with a new press release from the FAA ADS-B program office about ADS-B now being available in the Philadelphia area, that aircraft with ADS-B will receive both weather and traffic information service, even PHL TRACON will use it for traffic separation at 3 miles even when the aircraft are more than 30 nm from the radar site. It all sounds great. Now, if only the press release said everything rather than only what the FAA wanted released.
Reality is that unless you are one of the very few aircraft with a Garmin GDL90 978 MHz Universal Airborne Transceiver (for about $8,000 plus installation) and the Garmin GMX200 traffic multi-function display (about $11,000 plus installation), you will not be receiving anything in the Philadelphia area. In the immortal words of Strother Martin in Cool Hand Luke, "What we have here is a failure to communicate!"
The game plan for the ADS-B program (with ITT as the wining contractor) is to install more than 1,000 ground-based transceivers (transmitting on 978 MHz and 1030 MHz) across the U.S. national air space to hopefully provide traffic (on both 978 MHz and 1030 MHz) by year 2013. That sounds great if your aircraft has those receivers (and displays) and you are within reception range. The problem comes when an aircraft that has a 1090ES transponder (for ADS-B out) tries to determine the whereabouts of another aircraft that has a 978 MHz universal airborne transceiver. Unless both aircraft are within reception range of the ITT ground-based transceivers (minimum 1000' AGL for both aircraft if 37 nm away from the GBT), then neither will see the other. Remember even the FAA has decided that aircraft that fly above FL180 should have the 1090ES mode S transponder for ADS-B out. All other aircraft should have the 978 MHz UAT for ADS-B out (and in). Since all aircraft are at 0' AGL at one time or the other how on Earth (or above Earth) will they ever see each other when beyond reception of the ITT ground-based transceivers?
But, there's more. Now supposing you did order now and to be the first aircraft at Cross Keys (17N), NJ airport to get ADS-B in/out with the 978 MHz UAT. You'll get free weather (less content than WxWorx through XM and only when high enough to receive the GBT, i.e. 1000' AGL or higher when at 37 nm away), free traffic (again when high enough to receive it 1000' AGL or higher) and you only spent about $20,000.
But your hangar neighbor decided not to be a pioneer. He bought an XM receiver and pays $30/month for better content than you are getting (and gets it on the ground). He also bought a Garmin GTS800 traffic advisory system for $10,000 and gets active traffic information (12 nm radius ±10,000') even when on the ground. With the $10,00 more that you spent for less capability, he'll catch up to your costs after only 27.77 years of his XM subscription for the better weather content.
And even better still, both of you have a hangar neighbor at Cross Keys (17N) who decided 5 years ago to get the Garmin GTX330 (not ES since it did not exist back then) Mode S transponder. He convinced himself that there is no way he would ever buy an active traffic system (back then $20,000) so he got the traffic information service TIS through his Garmin GTX330 transponder. Result is that he gets traffic information at about 141' AGL with the ASR9 from PHL (13.9 nm away), and gets near continuous coverage 250 nm to the south through southwest and all the way to Portland (PWM), ME with a 200 nm swath. And he paid only about $4,500 for this traffic information service. Sometimes it is the old technology that works better for some.
The idea behind FAA's NextGen air traffic surveillance is "cost-shifting". How can the FAA get 250,000 U.S. aircraft owners to put in (and pay for) $20,000 worth of equipment so that the FAA can start decreasing some of the 300 ASR7/8/9/11 radar sites? Two simple words, FAR 91. They simply make ADS-B out required equipment for any aircraft to enter class A, B, C or any airspace above 10,000 feet by year 2020. Now some of the naysayers have doubts that the FAA would function without any of 300 radar sites in the country. You are probably correct but the idea is for other departments (such as DoD or DHS) to pay for the operation, not the FAA.
I am a firm believer in getting better equipment for the job rather than just buying the most expensive hoping that it might at least do some of what you need.
Getting a Garmin GDL90 978 MHz universal airborne transceiver (currently the only product with TSO C154 and includes a C145a GPS) means about $9,000 and being able to receive traffic only when in reception range of an ITT ground-based transceiver, and perhaps another aircraft broadcasting on 978 MHz. I have yet to see one FAA policy saying if the aircraft has ADS-B out via 978 MHz the aircraft can get rid of its transponder. In other words Mode C or Mode S will still be required for a vast majority of airspace.
It makes sense to me then to get a Mode S transponder that will also output the ADS-B requirements. You will then be very conspicuous to the PHL TRACON, aircraft with active traffic systems would even see your tail number for positive ID, and of course you'll meet the requirements for what the FAA has for the next 10 years and beyond.
FAA's decision to use to different frequencies (978 MHz and 1090 MHz) will be as successful as the Microwave Landing System from the 1980s and 1990s. No other countries are using 978 MHz for ADS-B and in fact all have chosen 1090 MHz (extended squitter ES version). I don't like it when the FAA makes a very big planning mistake like this, but I dislike it even more when 250,000 aircraft owners are expected to pay for it.