satelite radio problem

i have had sirius rad. for awhile and have had a problem from the start that i've lived with but it seems to be worse.I drive a int.9400and have the transmitter mounted on the air vent right by the radio,not 2 inches away but the trans.can't seem to overpower the terrestial stations.the manual say's if static is to lowd to tune to a quieter stat.but there are'nt any!all the wires,the power cable and the sat.anntenae wire have turned the reception of my radio into something incredible.i swear i can probably pick up the signal from voyager way out on the edge of the heliosphere!!I've had trucks pass by me and evidently we were on the same freq.'cause their station comes blasting in clear as a bell,while i have to change freq.literally every half hour except out like in the middle of south texas even then you could'nt belie.ve the stations it brings in.washington you can just forget it there is a powerfull stat.on every freq.someone told me you can adjust the transmitter strength but can't do it.on the settings menu it shows the sat. signal as all the bars are full but the terr.signal has none.do i have to mount it nearer the anntenae and if so where would it be located on my tractor?i would think having it this close to the radio itself would suffice,any help would be appreciated.

 

yes it has a fm"extender"but as i related i don't where the antenae is located is it in the center post of the windshield?in the windshield?the last time i tried the extender it made reception worse.also i have sirius

 

the thing is static is'nt the problem,the transmitter seems to be underpowered.it is about 2 inches from the stereo and i'm constantly having to change freq.like i said above i've had trucks drive by or have driven by them in a t/s who are apparntly on the same sat. freq.and there signal comes blasting over my stereo overridding radio stations and my transmitter alike and their at least 20 ft.away wherease my transmitter is less than 2 inches from my stereo.is there any way to increase the out put signal from my transmitter?