Okay...maybe someone with more electrical and ISS knowledge can help me out here.
First of all, I've been in frequent correspondence with Stefan on this issue and he has been providing terrific customer service. They're willing to ship me another ultrasonic sensor free of charge if mine is faulty. So I have 100% trust with him right now despite the problems.
Now, I'm noticing that I'm getting good data during the day when the sun is shining on the transmitter solar panel. When the shade sets in the data starts to go awry. I get a minute or two of bad data every 10 or so minutes and it picks up in duration throughout the evening until all of the readings are faulty. On Monday we had fog, mist, and drizzle the entire days with low solar radiation and the bad readings happened all day. Today the data was fine all afternoon until the shadows set in.
Again, this sensor runs on external 12VDC power and performs fine with solar radiation hitting the transmitter panel. What could be happening after the solar is lost? I should add that this is happening on two different transmitters too.
I'm assuming something is happening when the power source for the ISS shifts from the solar panel to the supercap. I considered snipping off the supercap from my older transmitter just for kicks and let it run off the solar and battery only, but I'm not sure if it would work with just the battery either. I want a long term solution too that won't cause me to drain through batteries.
Anyone have any ideas?