I am setting up a pioneer ax5 and have awful radio reception. I cannot use an external aerial. The wire aerial that comes with the amp is not that long, can I just replacce this / extend it?
Making the aerial bigger won't help much ,your best bet would be to buy some kind of indoor aerial an try and put it as near to a window as you can.Try looking at maplins for indoor fm aerials.Something like this.
I have just done a similar thing yesterday try this get several meters of cheap bell wire, I assume the aerial you currently have has a plug with two screws on the back? Undo the screws and replace current aerial with bell wire one cable in each, at the other end part the two cables to form a tee shape each branch needs to be 70 or 140 or 280cm depending on how large you can make it hang it as high as possible in the room, do not run the antenna cable near any other cables especially mains, this will not be great but should be a lot better than the one supplied.
Well to make a halfwave dipole you would need 71.32cm of wire each side ,but if you used the balun as pwiles says you would need a full wave dipole 285.29 of wire conected in a loop to give around 300ohm for the balun which would then give you a 75ohm input for the tuner. I used the standard formula, 468 / f MHz at 100mhz to calculate dipole lengthsI hope that clears things up a little for you