Satellite orbit height, speed and period calculator

the last couple of days I have been making a calculator to work out speed and period for a satellite at a given height.

Here it is: https://www.satsig.net/orbit-research/orbit-height-and-speed.htm

I have tested it a few times against known data and it seems to work, but I would appreciate someone else testing it and identifycing any problems or errors.

Best regards, Eric