XM or ADS-B?

txflyer

txflyer

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Fly it like you STOL it ♦
Well, I scrounged up the dough for the Garmin ADS-B antenna to go with GP, and I'm not real impressed. :no:

I think I liked my old XM weather more darnit.

The ADS-B does not do Jack Squat on the ground, and my Zaon picks up more traffic on every flight. Maybe I'm doing something wrong with it ..... :rolleyes2::confused:
 
I use it with foreflight/stratus and it's fine enough for me for what I want it for...and I don't have to pay a subscription...so you have to balance that. XM resolution is better and you don't have to bounce off towers to get it as you do with ADS-B. I can usually start picking it up at around 500' but pretty much never on the ground.
 
Have the stratus on Foreflight and xm on a garmin 496 like them both ,going to get rid of xm on the garmin because of cost.will keep the 496 for backup panel.
 
XM is better in that the resolution is much better and as you pointed out you can get it on the ground. The downside is the cost different. I recently picked up a Sky Guard Vision Pro. It has ads-b out which lights up all the traffic and the ads-b weather is the same as everyone elses.
 
For the cost ADS-B beats XM hands down. I use Foreflight and once the options were set correctly the ADS-B traffic is better than the Zaon. Out in the ADS-B boonies then the Zaon wins (of course). It's nice to have two independent traffic warning systems.

How's the traffic on XM? :rolleyes2:
 
I was able to see you on my iFly when we were heading from LNL to 6Y9
 
I went with XM on new avionics install, but I already had traffic. It sounds stupid to some, but I like the XM radio and didn't want two different installations and I really didn't want to use a portable with my new panel.:no:
 
tmyers said:
I was able to see you on my iFly when we were heading from LNL to 6Y9
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I'm ADS-B out via a 330ES which is why ADS-B traffic is good for me.
 
I personally prefer the XM the $35/month susbscription is nothing when compared to my $710/month hangar, $100/month on insurance and $300/month on AVGAS. On several occasions the XM TFR feature has alerted me on the ground before engine start in the Bahamas. Try that with ADS-B.

José
 
Clark1961 said:
For the cost ADS-B beats XM hands down. I use Foreflight and once the options were set correctly the ADS-B traffic is better than the Zaon. Out in the ADS-B boonies then the Zaon wins (of course). It's nice to have two independent traffic warning systems.

How's the traffic on XM? :rolleyes2:
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what options are you talking about?
 
wouldn't a $20/month ipad data plan give you you the same thing plus the other added items that may help? Just curious.
 
XM on my old 396 was better than ADS-B weather on my exp EFIS. It's all about $$$. I still miss XM.... and the radio was nice but it's $$$.

ADS-B weather on the ground is funny... I now get it at our airpark as soon as I'm out of the hangar but traffic has been flakey.

I do like the completely useless depiction of close-in traffic on my synthetic vision display... but it's just cool, not useful.
 
...Isn't the traffic on ADS-B (and even XM for that matter) pretty worthless? I don't pay much attention to it - everything I've seen is way up high...don't you need some new fancy transponder to even show up?
 
If you are in an area where someone has woke the system up by having ADS-B out you generally get everything in the area. Since I have the ADS-B out I pretty much see everything. the Adventure Pilot folks are still working out the ghost ship (me) that i occasionally see but that is much better now.
 
My trip was right at 5 hours, what does your Dakota true out at?
 
I think the ADS-B in on the GP antenna is just half the solution. Garmin is selling half what you need. And I fell for it.

Without the ADS-B out, like another member said, you don't 'wake up' anything, and don't see anything out in the boonies.

Weather comes in, but it's not as good as XM. Just my humble opinion ...
 
tmyers said:
My trip was right at 5 hours, what does your Dakota true out at?
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With the GAMIs it's pretty much select-a-burn: at 9 gph it's 130 kts, at 10+ its 135 kts, at 12 its 140 kts. If I go way up high it'll make 150 kts. Pretty much book numbers but I'm almost never at gross weight.
 
txflyer said:
I think the ADS-B in on the GP antenna is just half the solution. Garmin is selling half what you need. And I fell for it.

Without the ADS-B out, like another member said, you don't 'wake up' anything, and don't see anything out in the boonies.

Weather comes in, but it's not as good as XM. Just my humble opinion ...
Click to expand...

Sky Guard sells the transmitter only for those that already have the receivers.
 
tmyers said:
Sky Guard sells the transmitter only for those that already have the receivers.
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And that is where the problem exists... The SkyGuard TWX unit to run with a GDL-39 or Stratus 1/2 will run you $975. That means $1800 roughly to get a portable solution that won't be certified for the 2020 mandate (SkyGuard is trying).

Or you can pay $1500 for their complete solution that will work with WingX or Xavion -- again a portable, probably not certified 2020 solution.

The concern I have with the SkyGuard is that you still need the SkyGuard to ping to get the GDL-39 to pick up traffic. Which means unless you externally mount the antennae, the airframe will at time block it. It also means you are sitting in the cabin with a device sending out 30 watts...
 
kenjr said:
...Isn't the traffic on ADS-B (and even XM for that matter) pretty worthless?
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Yes, unless you are ADSB-out equipped, Foreflight traffic is pretty useless. Occasionally if there is a "out" equipped plane near you, you can pick up the traffic but I am finding that to be the exception rather then the norm.

...and that is why I am headed to the avionics shop next week to upgrade my transponder with ADS-B out...cuz when it does work, it it really a nice tool to have to improve your situational awareness.
 
txflyer said:
Well, I scrounged up the dough for the Garmin ADS-B antenna to go with GP, and I'm not real impressed. :no:

I think I liked my old XM weather more darnit.

The ADS-B does not do Jack Squat on the ground, and my Zaon picks up more traffic on every flight. Maybe I'm doing something wrong with it ..... :rolleyes2::confused:
Click to expand...

Nope... XM's radar depiction is higher resolution, and the ADS-B traffic is limited to planes that are broadcasting and planes that are on radar within 15nm and ±3000 feet vertically of them.

With the Stratus 2 and its dual-band ADS-B receiver, I'm seeing a lot more traffic, but it's generally just airliners passing over.

ADS-B is free, and for once you do get more than you paid for. Since the XM stuff is so expensive, the lower resolution is just something most people are choosing to live with.

kenjr said:
what options are you talking about?
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Go to preferences and turn off "filter traffic" and you'll see more traffic - But it'll be no-factor traffic. At least you know it's working. Remember that ADS-B traffic is NOT designed to show you non-ADS-B-Out-equipped airplanes.

tmyers said:
wouldn't a $20/month ipad data plan give you you the same thing plus the other added items that may help? Just curious.
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No. On the ground, sure, yes you'll get better resolution on your weather radar, but it's mostly useless in the air.
 
guess I was thinking that the ipad of phone could be used to asses the situation while still on the ground then use the ADS-B in once airborn. I typically see weather at about 500' AGL.
 
It's a designed conspiracy to milk every dollar out of your pocket.

XM does not give you traffic, but it's better weather, while ADS-B for $800 gives you crappier weather that's free, plus only ADS-B out 'pseudo-traffic' unless you pony up another grand or two, then the traffic will work on a temporary portable basis. :mad2:

I wish I had done like another member and just put the $800 towards the upgrade in ADS-B avionics in the da$h panel and be done with it. The portable was a mi$take imo. We are all going to have to do the mandate at some point.
 
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txflyer said:
It's a designed conspiracy to milk every dollar out of your pocket.

XM does not give you traffic, but it's better weather, while ADS-B for $800 gives you crappier weather that's free, plus only ADS-B out 'pseudo-traffic' unless you pony up another grand or two, then the traffic will work on a temporary portable basis. :mad2:

I wish I had done like another member and just put the $800 towards the upgrade in ADS-B avionics in the da$h panel and be done with it. The portable was a mi$take imo. We are all going to have to do the mandate at some point.
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We still have the XM and our passive Ryan TCAD picks up everything that responds to interrogation for traffic. Still, I plan to add the stratus to my ipad shortly.
 
I used our clubs stratus and give it a 5

The little weather there was looked like colored lego blocks.

Since I had seen weather using foreflight while on the ground via wifi in hi-res I was disappointed in the difference but still happy to have some weather vs no weather.

There was no traffic I could see so either adsb out wasn't working or I was all by myself today.

I do wish we had XM on the plane for the double benefit of weather and radio on long flights. Love me some Chill whenever I'm in a car with XM.
 
For Traffic I have the Monroy ATD-300+ connected to the 530W. It works very well in the Caribbean from the ground up. For Weather I use XM on the 560 and my smartphone when in the Caribbean (no XM Coverage). ADS-B is totally useless outside the US.

José
 

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tmyers said:
guess I was thinking that the ipad of phone could be used to asses the situation while still on the ground then use the ADS-B in once airborn. I typically see weather at about 500' AGL.
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Yes, this would work well - I usually turn on the Stratus right after I finish my runup, and I get a usable signal almost as soon as I'm off the ground.
 
I've used XM for six years and ADS-B for a few months. I've also used both of them on the same flight. I used a Dell Axim x51 PDA until early this year and then switched to a Nexus 7. Two months ago, I got a GDL-39.

Conclusions:

1 Even though XM receives data while still on the ground, I get my METARS much more quickly with ADS-B because of the quicker update cycle.

2 The resolution of XM NEXRAD on a high resolution device like an iPAD or Nexus is much better than that of ADS-B.

3 Other products are of equal quality from either source.

4 However, either NEXRAD is equally good for storm avoidance.

5 The reliability of ADS-B is much greater than that of XM. This is primarily related to the need with XM to power several boxes, all with different voltage requirements. A secondary issue is the weaker XM signal and need for the antenna to get a good view of the sky.

6 Back when I was using the x51 Axim, I was able to power everything with a single plug-in adapter. XM reliability matched that of ADS-B.

7 With a good three way power adapter for the Baron box, XM receiver, and tablet, XM reliability should approach that of ADS-B.

7 Garmin Pilot has a much larger user base on ADS-B then on XM. XM is an aftethought and there is a greater chance that updates will harm XM functionality.

8 My home airport is within a few miles of a major terminal, so I always have good TIS traffic on arrival and departure. That adds significant value.

Conclusion: either method is perfectly valid. Which is best is a matter of individual circumstance.
 
Paul I had three Garmin XM\WX receivers and all of them were able to receive weather well inside the hangar. On my 560 I only need one power connection for GPS and XM.

With recent government budget cuts I would be concerned about how the ADS-B\UAT ground infrastructure budget will be justified since the airlines don't use it. GA is the only user.

José
 
Piloto said:
Paul I had three Garmin XM\WX receivers and all of them were able to receive weather well inside the hangar. On my 560 I only need one power connection for GPS and XM.

With recent government budget cuts I would be concerned about how the ADS-B\UAT ground infrastructure budget will be justified since the airlines don't use it. GA is the only user.

José
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Once the equipment is installed, the FISB portion is cheap, at least cheap in terms of government. IIRC the annual service fee for the data was a few million. Reducing the paper clip line item a percent or so would produce that amount of money.
 
ADS-B FISB Nexrad has two products, a regional Nexrad product and a CONUS product. The regional Nexrad product is equivalent to the XM Nexrad in terms of the size of the individual cell. The CONUS product is blocky and its individual cell is 25 times the area of the regional product. So if you are comparing XM to regional, they have the same resolution. The regional product is between 150 NM radius around a GBT to 250 NM radius. Typically one can receive sufficient GBT locations when airborne to obtain a larger radius. I often see 300 to 400 NM around my position.
 
John Collins said:
ADS-B FISB Nexrad has two products, a regional Nexrad product and a CONUS product. The regional Nexrad product is equivalent to the XM Nexrad in terms of the size of the individual cell. The CONUS product is blocky and its individual cell is 25 times the area of the regional product. So if you are comparing XM to regional, they have the same resolution. The regional product is between 150 NM radius around a GBT to 250 NM radius. Typically one can receive sufficient GBT locations when airborne to obtain a larger radius. I often see 300 to 400 NM around my position.
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John,

While that may be true in terms of the resolution of the radar itself, the presentation of the radar on XM systems is vastly superior IME. I'm not sure if they're filling in gradients or making cells "rounder" via antialiasing or something, but it just looks better.

That said, for me, it doesn't look enough better to pay for it.
 
You would think ADS-B would be putting pressure on XMs market share, and those subscription prices would go on sale, but no joy so far....
 
flyingcheesehead said:
John,

While that may be true in terms of the resolution of the radar itself, the presentation of the radar on XM systems is vastly superior IME. I'm not sure if they're filling in gradients or making cells "rounder" via antialiasing or something, but it just looks better.

That said, for me, it doesn't look enough better to pay for it.
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I agree XM looks better, it seems they round the edges and do a better job of processing the data. I have both in my Bonanza displayed on my GNS530W and they have a similar look, but they are not identical.
 
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