Today I flew up to Talkeetna for lunch. The route takes me right past Anchorage. Scuddy day with some rain so I thought I'd fire up the Garmin GDL39 and see what ADS-B would show for weather and traffic. Saw some traffic but not all as I don't have ADS-B out. An airliner flew a pattern around me and it didn't show up on ADS-B although I didn't think much about it at the time as I was too busy looking for other smokers. Weather display was non-existent no matter my altitude. The trip back was similar except this time three airliners did a pattern around me and none of them showed up on Foreflight or Garmin Pilot.

Altitudes ranged from 1,500 MSL to 3,500 MSL to 5,500 MSL. Never did I get any weather information on Foreflight or Pilot even though I could see an ADS-B tower on Foreflight. Turn off the GDL39 and with a cell signal I got a weather display. Back to ADS-B and nope.

Question for you airline jockeys. If I'd have had ADS-B out would the airliners have shown up? Obviously at least Alaska Airlines (that's what these four were) doesn't have ADS-B out yet.

Very limited value this ADS-B, at least where I fly. Certainly useless for weather info.

You have some kind of issue with receiving data from the ground stations. Move your antenna around to see if that helps. I used a 39 for a while before getting the 52 and have it sitting on the glare shield. No issues out to 100 miles at a few thousand AGL unless I'm going directly away from the station, then the range might drop to about 50ish miles.
If you have Out then your airplane will talk directly with other Out aircraft, no ground station needed.

So I did get an ADS-b in receiver, and while flying around in the sticks, I don't think it does a lick of good, but in the Anchorage bowl on a nice day, there is a LOT of traffic, and most of it shows up. Between ADS-b out and 1200 vfr squawking aircraft on radar, nearly all of it shows up on the screen since it's broadcast (or at least that's my theory).

So I would say that if you don't have ADS-b out on your airplane, at least get a transponder and squawk VFR. That way when I'm flying through Los Anchorage I can see you.

For my bearhawk, when it's done I'll get ADS-b out, but more importantly, I'm going to have lots of flashing lights.