ADSB help

[wilddog]

Thanks for all the replies. To clarify, this is for VFR flying. Would only receiving adsb signals from aircraft really be much of a disadvantage? There seem to be airliners overhead nearly everywhere.

[BobTurner]

Originally Posted by wilddog

Thanks for all the replies. To clarify, this is for VFR flying. Would only receiving adsb signals from aircraft really be much of a disadvantage? There seem to be airliners overhead nearly everywhere.

Assuming you avoid all the aforementioned airspace (basically anywhere where mode C is now required) then you won't be any worse off than you are today. Remember ADSB-in is always optional. If you have ADSB-in but not -out, you will not get traffic advisories from other aircraft like yourself, with no -out. And, BTW, to see all ADSB-out aircraft, you'll need a dual frequency ADSB-in receiver.

[GalinHdz]

The easiest way to think about it is "if you currently require a transponder to operate in that area (Airspace) you will be required to have certified ADS-B OUT come 2020.

[bhester]

Originally Posted by wilddog

Thanks for all the replies. To clarify, this is for VFR flying. Would only receiving adsb signals from aircraft really be much of a disadvantage? There seem to be airliners overhead nearly everywhere.

Yes but they are too high most of the time. I don't remember the details but you will only receive if they are close enough distance from, distance above or below, you, it is limited, just don't remember the details.

You will not see traffic that is 20,000 ft. above you in normal operating mode, and it will not send ADS-B traffic to your display.

[noelf]

The 2016 FAR AIM section 91.225 covers where ADSB-OUT will be required. THere is a fairly new AC (AC 90-114A) that describes this fairly well.

In summary, OUT will be required within the Mode C veil lateral boundarys of Class B from the surface up to 10,000ft.

OUT will be required within all of the Class C airspace and then within the lateral boundarys up to 10,000ft. The OUT requirement does not encompass the area below the outer ring of Class C to the surface. THis is what Figure 3-1 of the reference AC shows.

However, there is some serious discussion within my EAA chapter membership some with the university level English graduate teaching pilot folks as to the "proper" use of the words "and" as used in FAR 91.225 (d), (3). I can not say who is right or wrong in this language interpetitation, but reading the FAR could imply the OUT requirement may also be required below the Class C outer ring to the surface.

And as always, Out will be required above 10,000 ft MSL.

There has also been some discussion as to whether ATC will honor Flight Following if the requesting aircraft does not have functioning ADSB OUT. I don't remember where that came up.

Hope this helps.

[BobTurner]

Originally Posted by bhester

Yes but they are too high most of the time. I don't remember the details but you will only receive if they are close enough distance from, distance above or below, you, it is limited, just don't remember the details.

You will not see traffic that is 20,000 ft. above you in normal operating mode, and it will not send ADS-B traffic to your display.

You're trying to recall the "hockey puck" shaped area around you (I too forget the size but I think it's 3500' up, 3500' down, and 15(?) miles in diameter) BUT that is the volume for which the ADSB ground station will send you traffic. Since he doesn't have -out, he won't trigger the ground station and he'll hear nothing from them (unless a nearby aitcraft triggers it, then he'll get the traffic that is within that other aircraft's hockey puck volume, some of which may impact him too). However, he may get direct air to air traffic from a long ways away. I use a Skyradar D feeding both a GRT HX via USB, and an iPad via wireless. On the HX I have a filter turned on to limit traffic displayed to those within a few thousand feet of me vertically. On the iPad the filter is off, and there are targets everywhere! As I said before, you need a dual band receiver to see all -out equipped aircraft if you do not trigger a ground station. All of the airliners are on 1070 MHz (transponder frequency) while some (many??) GA airplanes are on the UAT frequency.

[DennisRhodes]

My Navworx 600Exp is a single frequency device for both In and OUT ADSB signal using the UAT frequency. I believe 3500 ft above and 3500 below is the limit that ATC will send you traffic , also I usually never have any reports thats more than 15 miles away. With that you do get ALL Traffic thats got a transponder "on" in contact or not in contact with ATC which leaves J-3s and others still out there. VFR Still requires "Look for yellow" and other colors out the windshield.

[BobTurner]

Originally Posted by DennisRhodes

My Navworx 600Exp is a single frequency device for both In and OUT ADSB signal using the UAT frequency. I believe 3500 ft above and 3500 below is the limit that ATC will send you traffic , also I usually never have any reports thats more than 15 miles away. With that you do get ALL Traffic thats got a transponder "on" in contact or not in contact with ATC which leaves J-3s and others still out there. VFR Still requires "Look for yellow" and other colors out the windshield.

Well, strictly speaking, you'll miss all mode S traffic until you're high enough to access an ADSB ground station. And you won't see any non-ADSB traffic that's below radar coverage. For example, at my home airport, radar coverage only comes down to about 1500'agl, so no non-ADSB-out pattern traffic shows up on an ADSB-in device. Yes, you still have to look.

[AllThumbs]

In practice, ground stations are sending lots of traffic up and are not directional, so you can "see" a lot of traffic both directly from Out-equipped aircraft and indirectly from the ground station feeds to other aircraft. But if you do not have Out you cannot guarantee that your immediate airspace will be included in the traffic feed from the ground stations. Bob is correct that few airports are line-of-sight to a ground station but most are line-of-sight by the time you are about 1000 AGL.

The FAA has a cool KML file you can download to display the ADS-B ground station coverage by altitude. I'll try to find it and add it to this post. Here it is: http://www.faa.gov/nextgen/equipadsb/airspace/

Distance filtering of traffic typically takes place at the display end - not the ADS-B receiver. For example, GPSMAP x96 devices only draw up to 8 targets that are within 7 miles and +/- roughly 3,000 ft - targets outside that range are ignored. Other displays, like ForeFlight, can display dozens of targets at long ranges.

As more aircraft add ADS-B Out, more traffic will be reported by the ground stations.

Some nice side effects of adding ADS-B out: You can use your Flight Aware account (you do have one, don't you?) to track your plane and even send text messages to loved ones when you take off and land. My wife is currently getting pelted with texts whenever I fly the -6. This can be a problem if you do pattern work...

Since you mentioned the ADS600-EXP, there is now an iPhone/iPad app to configure and test it more easily and the EXP is a very cost-effective solution for legacy installations. We installed an ADS600-EXP in a D180/GTX-327 equipped RV-12 and most of the wiring hook-up can be done at the back of the transponder.

A side-effect of installing that box is that I ended up writing the App for NavWorx. It was just accepted by the App Store. Sorry - shameless plug.