Circle speed and rep rate tests
	diameter		speed		rep rate		comment
	inches		mm/sec		kHz
	0.5		10		10		better
	1		10		10		acceptable
	1.5		10		30		acceptable
	2		10		40		acceptable
	2.5		10		40		acceptable
	3		12		50		acceptable
	3.5		12		50		acceptable
	4		12		60		acceptable
	4.5		13		60		acceptable
	5		15		70		acceptable
	5.5		17		85		acceptable
	6		20		100		acceptable
	6.5		20		110		acceptable
	7		25		120		better
	7.5		30		130		better
	8		30		140		better