Ultra Start U3500A-XRLT antenna issues

I was wondering if anyone has had a problem with Ultra Start U3500-XRLT antenna's which seem to pop up as range issues.  Currently the temp range here has been +5 to +35f.  Last Fall and this spring we saw about a 25% to 35% failure rate out of 200+ units. From the last shipment (2weeks ago) it seems we are at 100% for 9 units.  The earlier units would slowly fail over 2 weeks to 1 1/2 months, these new units all have range of less than 200' over flat ground and less than 20' from inside a windowless building with metal siding.  Oh, yea...we did check the batteries in the remotes and "shored up" the contact points.

To confirm that it was not a problem with RFI in that specific area we installed an Astroflex 4204, and a Compustar 2WFMAS in identical trucks and got ranges of approx. 1200' and 900' respectivly, from inside the building.

Ultra Start has told me that we are the only ones with this problem and that it could be an installation problem, though I doubt it because we install approx. 2800 autostarts per year and this model is the only one with ongoing problems.

Can anyone shed any light on this problem? 

Well, I happen to know alot about these, so...

Ultrastart(AST) is designed where i live(edmonton). The 3500xr's in Canada were last years model. They had a black antenna with red leds and a blue/silver remote with a lid. The new ones are u3560xr's and have a transparent antenna with blue leds, and the new remote with no lid. I know the models differ in Canada then from the US, but I'm not sure which ones are which. The am units still have a black antenna/red leds, and a black remote as well.

Here in the country, the XR(FM) units are getting 1 to 1 1/2 miles of range. That is about the only problem that they don't have. Watch out for units with wrong parts or modules in the wrong case. The am and fm units are interchangeable except for the antenna and remote.

You should check for a remote that is transmitting, that is still in stock in the box. Go for a drive after install and re-program the remotes. That would be my bet. I know one of the the tech guys at B&B Electronics, and he built a remote finder out of an antenna to find remotes that were transmitting in the warehouse and screwing up the installs at Certified Radio(same building).