I am installing a Sirius system in a new car and my wife doesn't want the antenna to show.. I ordered a mini- 1 1/4 x 1 1/4 inch Sirius / XM antenna off the INET Auction. The antenna is just the size I wanted, BUT.. the signal strength from it only registers 3 bars whereas the signal strength on the 2 1/4 inch round antenna that came with the Sportster 4 is max... Measurements taken on same receiver with identical antenna location. The smaller antenna says Delphi XM on it but the seller told me it was the same as Sirius and would work the same.. It doesn't.. Is it the smaller size that is causing the reduced signal strength or is it the fact that it is made for XM and I have been sold something that won't work as it should when connected to a Sirius Radio?