Re: Stargazer GPS in canyons like lake powell
It does not need as many signals as a GPS locator does but I have had problems with some parts of the Shuswap Lake as mountains rise up to 3000' from the lake. It gets confused and locks for a while. Very frustrating when you don't know what is causing it but easy to anticipate once you've had it happen. Location of the puck made a difference but I suspect you could have a problem in tight to the canyon walls on the south side. Powell is far south of the Shuswap so it may not be an issue. Most satellites are on equator.
Overall I am very pleased with the Stargazer and would not want a paddlewheel. I have had mine since the first month they came out and I suspect the newest ones might be set to adapt better than mine.
So, yes it can happen but I suspect you will be happy with it. I have not run my boat on Powell.