Wethead FM antenna - why does it move?

[realshelby]

I didn't pay for Sirius satellite radio for this trip. Tired of their games....So I had tunes on a flash drive and trusty, cheap FM radio. 

 

When traveling you find a station and listen for a bit...until it starts fading. Well, I had a moment and decided to try raising the FM antenna. I have always wondered why BMW made it a swivel mount? Well, the difference in reception is rather dramatic! Find a station with a bit of static and try raising your antenna to more vertical. Being a HAM radio person, I understand what is going on. I don't know why I didn't try it before! 

[reg26]

I will have to try that !

 

[Paul De]

I assumed that pivot had a purpose and noticed better reception in the up position too. I actually use the radio quiet a bit and leave the antenna in the reclined position around town.  Going out for a long ride into countryside, I'll push it up.