Safety finish rule & circle radius

One point of discussion in our little group has been:
How do you determine your height above the ground?
Altimeter? Pressure altitude? But there's a big
storm there. What's happened to the pressure? What's
the effect to the altitude shown on your altimeter?

GPS altitude? Which of our GPS's show gps and/or pressure
altitude?

BB suggested allowing the CD to call off the task.
This means you have to have your radio turned on.
Up to the pilot to keep the radio on.

Dang hard for me to thermal, especially when digging
out, which I find myself doing a lot, with the radio
on.

Ray Lovinggood
Carrboro, North Carolina, USA