The chart I used said that for 88.1 frequency, the wavelength should be 3.4 metres. I wanted the run to go outside to see if the broadcast would reach farther. When comparing the 3 antennas I made, 85cm, 170cm, and 17 metres, the longest one does work marginally the best, giving me the strongest signal in my farthest cabin. The 85cm one works fine in the car. I was hoping for a bigger improvement with the longer run, but can live with it for now. I see that Sat. Radio Source is now selling a short fm out antenna that looks good for $12.99. All told, my 3 antenna experiment cost me $14.00.
I'd still like to find a way to boost it a bit more though.