Electronics, Lighting, & Gadgets - Help with the Garman 705 Cadence Sensor

Just recently I changed the battery on my cadence sensor. After changing the battery I started getting some real strange reading it was showing my cadenced at a real high number around 170 RPM while I was riding. I played with the sensor and adjust it so that the magnet was in line. After that it appeared that I was getting more accurate cadenced reading...BUT my speed is about 2 mph slower than I am actually going.

Yesterday while I was riding I disable the cadence sensor and I started getting accurate speed reading while operating off of the GPS only.

What could be the reason for the inaccurate information? Any correlation to changing the battery?

Two things come to mind:
1) When you moved it to fix the cadence alignment the speed alignment was thrown off.
2) Your wheel size is wrong on the Edge. This was a known bug on one of the SW versions of the 605/705.

I recently started riding my trainer with a new Garmin 705. I repeatedly see my speed (picked up on my sensor) drop to approx. 1 mph and then pop up to my training speed and then drop back down to approx. 1 mph again and then back up. This is repeated anywhere from every 30 seconds to approx 3 to 4 minutes throughout my indoor rides. Any recommendation as to the fix or am I just destine to wait for an accurate speed on my bike from the GPS once I get to riding back outside?

Turn the GPS receiver off in the Edge.
menu/Settings/System, set GPS to "GPS off"

Thanks,
I'll give it a try!