Yeah, the black antenna on the trunk is your XM antenna. I'm still not sure why the
original posters reception is bad with the top down and not with the top up.

__________________
2008 Deep 2.4L - Premium Package - Preferred Package-
Convenience Package - 5 Spd Auto - Dashhawk - GMCAI - Flowmaster 40
http://i40.photobucket.com/albums/e2...dee/sigpic.jpg

Could it be the top is contact the cable when it is down. I don't have my car near by so I can not verify that it could cause a problem.

Yes, there is an XM antenna. For stock XM it is installed on the trunk lid. See my pic below. the "puck" part of the antenna is for XM and the stub sticking up is for OnStar. For after market XM installs there is usually a small magnetic mount "puck" that is installed on either the roof or trunk lid for a hardtop car or the trunk lid for a convert. I have seen some install the antenna on the dash but it will have reduced reception mounted there. Buildings, dense trees, hills, can block XM reception, especially the farther north you go. The XM satellites actually are over the equator with their transmission antennas pointed to North America. My XM cuts out quite a bit in my rural area due to obstructions to the south such as trees and steep hills next to the roads.
I would check with your installer to see where they mounted the XM antenna.

__________________
2008 Aggressive GXP, 5 speed, fully loaded. Ordered 8/1/2007, delivered 9/14/2007.
NASSOA Founding Member

I have the J style shorty as well. I get great reception around LA. Its extendable and will just reach the roofline of the car when out fully.

__________________
Victoria
2007 GXP Manual.

Thanks for all the help. I took the car to the dealership for an oil change and had them to check the antenna problem out. Seems like the cable was not connected and since then I have had good reception with no other problems. The ideas, pictures and willingness of others to help with any issues make this site the BEST!
BGW

Has anyone installed a powered up/down antenna?

Yep.

some assembly required [power antenna mod]

__________________
"Muirne" --- Envious, ebony leather, LSD/ABS/AC/Monsoon w/6CD changer, mats, splash guards, DDM Stage II S/C, DDM stainless headers/cat/exhaust, DDM 4-piston brakes/slotted rotors, Probeam, Backbone, black "stubby" antenna, Lil' Chromies, K-sphere pedals, Kazera KZ-L wheels, the TWEETY door unlock/lock button, Garmin nuvi 750 GPS, High Note horn, Brushed Al door sills, etched/lighted WindRestrictor, white LED map/footwell lights, 3rd brake light pulser. --- She moves!
NASSOA Founding Member

I live in a metro area and have no issue with reception. Note 3/8" thick stainless washer under crown nut.

Can't get any shorter than this:



DD

__________________
Future so bright I have to wear shades!!!

Mean GXP (VIN 117835 11/06 )
Name: Growler
Name: Growler (Vin #4878) Traded for Mean GXP 3/19/07
Mean, dark side, ebony leather w/red stiching, LSD, ABS, AC, Monsoon 6CD changer, mats , headliner, stability control, XM, power pkg., convenience pkg., chrome wheels, sport peddles, Fiam Air Horns, Magnaflow, De-badged, shortened waste gate rod mod.
Garage Mates: 2005 Yamaha FJR1300, 2003 Yukon w/K&N CAI, 2003 Honda CRV

I love it!!!

__________________
http://www.myspace.com/squirrel_boy1
~~~~~~~~~~~~~~~~~~~
Pontiac is car...
Saturn has rethought it's image...
The time has come for the enthusiasts...
NASSOA
Founding Member # 21
~~~~~~~~~~~~~~~~~~~