XM Radio Woes

[aetatis]

Just to add my 2 cents I haven't had any problems in GA.

The big test will be the 1200 mile trek back to the hinterlands
of NH! Then I will see just how great XM is...

Aetatis.

[SpottyJ]

aetatis

When will you be in NH?  We are having a mini GTG on April 17th in southern NH

[Chief]

I'm 99.9% sure I have fixed my problem, and with the most unlikely of solutions.

Gave my Avalanche the big bath the weekend before Easter.  Generally I don't climb up on the cargo panels to wipe them down along with the roof, but the pollen is flying (I awoke to a blue with lime green fleck Avy this morning) and it had dried on the back panels.

While up there I gave the roof a good wipe down, something it hadn't had all winter.  This included getting the XM Radio antenna.  Well surprise, surprise, surprise.  Although there wasn't visible crud on the antenna it seems as though wiping everything down up there did the trick.  100% coverage as good as day one.  Drove to Federal Way and back yesterday no issues - no issues in the Edmonds bowl.

I can only figure there was some sort of particle pollution on the roof that was blocking the signal OR there was a local area issue.  There just isn't any other logical explanation for the sudden healing of the system.

[SpottyJ]

If the signal cutout plagues you, and you have an older antenna, try the newer type found on the '04's: P/N 15205583. It's supposedly improved, but to what extent, I don't yet know. Maybe just "Bigger - Better - Faster - Stronger"... ?

Per GM Tech LinK:


New Antenna Technology
Beginning with the 2004 model year, a new XM antenna is being installed on some vehicles (fig. 7). The list includes Avalanche, Denali, Denali XL, Escalade, Escalade ESV, Escalade EXT, Sierra, Silverado, Suburban, Tahoe, Yukon, and Yukon XL. The DeVille, Seville, Bonneville, and LeSabre will switch to this new antenna mid-year. And also mid-year, the 2004 Envoy, Envoy XL, Envoy XUV, Rainier, TrailBlazer, and TrailBlazer EXT will switch to a different new antenna (fig. .

The XM antenna used in the 2002-03 model years included two different elements, one to receive signals from the satellites, and a second one to receive signals from the ground repeaters. Two coax cables were required. The new antennas use one element to receive both sets of signals, and only one coax cable is required.

TIP: The two types of antenna cannot be interchanged in service.

[sperry]

 I missed that "tip" part  .`Good thing you didn't!

I wonder if it's the hole pattern or the `04 module has the two antenna inputs internally.

When you split, there's losses. In order to minimize this, they no doubt they did this because it was the easiest, most practical approach.

So, the later antenna may not really work with the earlier XM modules...

[SpottyJ]

Sperry:

That's what I am thinking, not sure it can work with earlier version. Someone on the site has a factory XM w/Bose system on auction at eBay.  What would we need to see to determine if the inputs are the same?

The CAFCNA member has all his parts pulled out.  Maybe we can ask him for a photo of the input jack on the XM RX?  Thoughts?

edit:  I just found two CAFCNA members with their systems removed, what should we ask them?  ( I know nothing about electronics)

http://www.chevyavalanchefanclub.com/cafcna/index.php?board=33;action=display;threadid=25354;start=msg394920#msg394920

http://www.chevyavalanchefanclub.com/cafcna/index.php?board=33;action=display;threadid=26640;start=msg416837#msg416837

[Ambalanche]

No problems here, sometimes if I go under some thick oak trees I'll loose the signal for a second, but other than that it's cool!  

[SpottyJ]

I live in New Hampshire and my XM cuts out during the summer (leaves on) all the time, in the winter just a few places here and there.  I was surprised that trees would cause cut out.  My FM/AM RX don't have this problem.

[sperry]

Thanx Spotty...
 I followed up on the pm - somewhat.

I noticed the guy selling that HU on E-bay saying it doesn't have to be unlocked... Hmmmm, well ok then.
 I wonder when the buyer will pop up here with the HU & XM unlock questions..?

[SpottyJ]

Sperry:

An observation I made:  I have an '03 w/ XM.  Cuts outs often in the same areas on my daily commute.  Today I drove an '04 Avalanche same route and no XM cut out.  So, in my limited testing, the '04 XM antenna receives better than the '03 antenna.  What do you think about swapping an 03 antenna w/ an '04 antenna?



Edit: typo

[sperry]

I looked at the prints of the `03 & `04 XM module connections (Av.). Although they have different document numbers, the antenna connections are the same on each print!
I looked at an `04 car (Grand Prix) XM print and it had a dual cable antenna... Figure that!

[sperry]

This is the Grand Prix's print:

[sperry]

This is the `04 Av's XM receiver print:

[sperry]

This is the `03 Av XM print...

For those of you who don't know yet, you click on the image's link to make them mo' bigerer....!

[SpottyJ]

Sperry:

Here is an under headliner pic of an '04 XM Antenna Mount.  Note, just one brown wire coming from antenna.  Any idea if an '04 antenna will fit an "03?  I don't have pics of an '03 mount.

[SpottyJ]

Here is where the wire of the 2004 model enters the XM Box behind the glove box.

[SpottyJ]

Here is the end of the plug.

[SpottyJ]

The XM Box (Delphi) on this '04 is Part No:15125061 (I think, I was reading via a mirror).

The Number on a UPC type sticker on the brown antenna wire had:  151224307.

Here is a shot of an '04 Avalanche antenna from the outside.

[SpottyJ]

The '03 may have one or two wires, the '04 has one wire coming from the antenna.  I believe the single '04 antenna/wire provides better reception (based on my one day test).

Need to know if '04 antenna will mount to roof of '03?

Need to know if '04 antenna cord will plug into '03 XM Box.

And is that all there is to it?

Here is the '03 from a GM Teck Link Photo.

[sperry]

Hmmmm, anyone want to pull their `03  headliner down?
that `04 peek is certainly a single coax.

I can see by the fact that an `03 to `04 comparison had a difference, that it's enough to look into this further.

Well, judging by the prints, they're the same type of connection. It's the cars that changed.
However, I would have to contact a tech at my dealer and see if he remembers. I want to run an OnStar question past him anyway, so I'll lump this in..

I presume you have both part numbers; at least the `04 P/N? (I'd like to compare notes if you retrieved it elsewhere.)

Lots of conflicting info now..  

BTW do you know the build date of that `04?

[sperry]

That's looks exactly like an SMB connector, embedded into a GM connector shell.

The antenna is different than the ones I've seen on `04's (Av's) too.. Now, since there is a pigtailed wire that only shows on the car schematic, are we sure this isn't that car one? (The techlink one.)

[SpottyJ]

I presume you have both part numbers; at least the `04 P/N? (I'd like to compare notes if you retrieved it elsewhere.)

Lots of conflicting info now..  

BTW do you know the build date of that `04?

Sperry:

The limited part numbers I have are from reading the parts on this '04 Avalanche.  As I said I could be off on the numbers of the '04 XM Box as it was installed and was reading upside down with a mirror!  But, I belive I have it correct

The build date -  Don't have, except to say the cargo covers had a February 2004 manufacture sticker on them, the truck was delivered in March 2004.  That's as close as I can get to a build date.  I no longer have access to the truck.

[SpottyJ]

That's looks exactly like an SMB connector, embedded into a GM connector shell.

Sperry:

Don't know what an SMB connector is, can you help me out?

The antenna is different than the ones I've seen on `04's (Av's) too.. Now, since there is a pigtailed wire that only shows on the car schematic, are we sure this isn't that car one? (The techlink one.)

 Sperry:

The Techlink one, I cannot be sure what model/version/vehicle that is for.

The outside cover of the antenna on the techkink photo looks like my '03 antenna.  The '04s have a more box shape,  see the pic I posted above.  The '03s have the fin in the middle.

To all:

Can anyone out there confirm if an '03 XM antenna has one or two leads coming from the antenna? Someone must have pulled their headliner.

[sperry]

The `04's Ive seen was a sharkfin like the `03's but had a higher base section like in the photo, all moulded together.

The observation of the connector type was just the center metallic part, not the green plastic retainer. That connector appears as if it's an SMB connector.

A PDF of some SMB connectors

SMB's are one of several types of snap-on RF small cable connectors, commonly used in lower power microwave/UHF devices.

Good to use if one must adjust cable length or occasionally disconnect device parts. Another "similar use" connector (SMA) is an incompatable thread-on type for more secure connections.

[SpottyJ]

The `04's Ive seen was a sharkfin like the `03's but had a higher base section like in the photo, all moulded together.

I have only seen the '04s like the pic I posted above on the silver Avalanche.

The observation of the connector type was just the center metallic part, not the green plastic retainer. That connector appears as if it's an SMB connector.  

I think the one in my photo from the '04 is Yellow.


As usual, thanks Sperry for the info, and link to a SMB.  Learn more everyday.

I would love to figure this one out so I, and others, can improve their reception of their XM receivers.  Living in New Hampshire (fringe area/few repeaters/poor satellite angle) makes for frequent cutouts.