its great.. EXCEPT int he summer in the woods.. too many tree cover tops..
but fall winter and spring its rally great..
I test mine many times.. over know distance.. and in 10 miles i am always less
then 0.5 miles off...
on one rider 18.6 miles measures with a wheel i read 18.2 close enough..
show speed alt distance etc.. about $200 or less when on sale.. look in
boat catalogs..
i got mine from vit electronics in fl 325 687 3888
if i did not live in the wooded mtns.. it would all year..
no the hrm does not interfer with it.. gps sat freq very high hrm is 50khz
approx..
i never had a problem even when i put it in my pocket.. gps that is..
but to do it right you need the extranl ant where it can get a full 360 deg
clear view of the sky..
leaves are off the tress.. so i just put new batteries in the unit and put the
ant bak on the helmet for the next time we go out..
no matter what else you hear.. it does work.. anmd well enough for me to
measure trails..
roger