Autoleads PC5-52 Signal Filter

hi all.
just fitted my subaru with an alpine stereo and had to get some Autoleads PC5-52 Signal Filter ??? i put it all back in together and still find the radio is tuning in and out as i drive along. can anyone help ? Or can anyone tell me what do i connect the blue wire to?

many thanks

What impreza you driving??

Who told you ya needed this aerial adaptor thingie? Is it a legacy you have with aerial built into back window?

the blue wire is a remote wire for an aftermarket amp AFAIK...
is it a legacy????
jap or uk???
had alot of sh1t fitting an aftermarket radio to a jap b4 for my brother-in-law....
there are 2 ariel points behind the radio down near the floor which both have to be used!!!!

had a look at that audioleads thing on google and it looks like a band expander to me. is the alpine stereo a jap stereo or is it an irish aftermarket one. if its an irish stereo it doesnt need a band expander but if its a jap one it will. if it has an earth strap make sure it well grounded(tightened) i fitted an irish sony single din stereo into my b4 and ive had no problems. there was only one stereo connection for which i had to get an extension cable for it to reach the back of the stereo. if the car has had a jap satnav it might have what look like antenna connections similar to our type that would have been used for the jap satnav antenna