Aftermarket stereo Q

Hi all
I mostly lurk around on here and absorb info (when possible). I inherited a 03 Golf TDI when my brother passed away late last month. Lots of upgrades done to it which I will post maybe with some pics later.
My question is, stereo reception sucks. He lived in the city where it didn't matter. I live 80 miles from the nearest big city, but our local city has a decent station I like to listen to and I can't pick it up even 6 miles away. My other vehicles have no problem. I have been searching everywhere and I can't tell if the antenna has an amplifier that needs power or not. I am pretty sure the vehicle did not have the monsoon system. I do have the Bentley you all refer to and maybe I just am not looking in the right spot. Hopefully one of you can help me. I am not new to working on cars, in fact have 20 years of professional Toyota experience. I am learning much more about VW every day now ?. So far I love the car. Toyota never did this power and torque combined with excellent fuel economy.
Thanks for helping and I hope this is in the right section.....
Aaron

All MKIVs (which is what you have) have a powered amplified in the antenna base.

Are there any electrical mods on this car? Maybe the antenna amp got damaged or unplugged along the way...

If it has an aftermarket stereo, the power to the antenna may never have been connected in the first place. You may need an adapter that provides power to the antenna.

Does the car have the original mast antenna? Some of the stubby billet aftermarket antennas make get poor reception.

Yes it has aftermarket radio, looks like factory antenna. I pulled the radio out and it all appears to be wired correctly, but.....
Will dig further in the Bentley know that I know it should be powered.
Thanks guys!
Aaron

So, there's a wire coming off of the antenna wire that is connected to 12v somewhere? Here is an example of a potential adapter:

https://www.crutchfield.com/p_12040VW54/Metra-40-VW54-Antenna-Adapter.html#&gid=1&pid=1

Another question would be how does the gasket look between the antenna base and the car roof? Is it cracked anywhere? Sometimes, water can leak into this area and short out the powered antenna. It's rare but can happen.

Ok, that answers the question I was trying to answer. I seen the blue wire connected to the 12v switched power wire. I have been trying to figure out if it was supposed to be powered or grounded. You just answered the one question i haven't been able to find! You're awesome! I sure hope I get the hang of VW wire diagrams soon. I think I was spoiled by Toyota ones ��
Now I will be double checking the base itself.
Thanks again!