Measuring The Speed of Light Using a Shortwave Radio

[ChrisSmolinski]

I thought it would be interesting to see whether or not it was possible to crudely measure the speed of light using a shortwave radio and a time station...

http://www.hfunderpants.com/?p=332

[weaksigs]

This is a really unusual topic to be shared anytime but on New Years Day after a bash??
Oh you must've stayed home and listened to pirates all evening!
Is this one of those examples of having; "Too much time on my hands"??

Interesting regardless.... actually pretty neat!!

Hmmmmmm.....

weaksigs

[Newfoundland DXer]

Quite a fascinating little experiement.

Given the lack of resolution on the time scale, the fact that your experimental results were within 3% and 1% of the accepted values is quite amazing.  

Some people may question whether it is acceptable to neglect the height of the ionosphere.  Taking an average height for the ionosphere of 300 km, and average earth radius 6371 km, assuming the signal is at an average height of 150 km (it may be a little less due to curvature), and that the circumference is proportional to radius, this would increase the distances by 2.35%.  This is not significant, given the existing margin of error.

Thanks Chris.

Cheers, Terry

[LanceLovejoy]

Very ingenious experiment, astounded that you could use your data to ID a signal taking the long path around the earth to reach you.  Physics teachers far and wide should take note!  And here I thought those time signals were just interesting listening!

[ChrisSmolinski]

What I'd like to do next is get WWV via long path. I need to run some propagation forecasts and see when/if that is possible.