**PARKING NOTE: The posted speed limit on Murray Hill Road in 30 MPH but this is Maryland so most folks drive about 45 MPH so PLEASE exercise caution when parking along the road. We recommend you park on the west side of the road, and watch for traffic because it can move very quickly.**
There is limited trailhead parking along the side of Murray Hill Road at N 39° 09.581 W 076° 51.148, just south of the bridge. It's possible to reach the cache via a few different trails from this parking spot. The 3.5 rating is based on the most challenging route we could find to the cache.
First-To-Find prize is a 2007 APLCachers geocoin.
The Johns Hopkins University Applied Physics Laboratory (JHUAPL) is a not-for-profit center for engineering, research and development. APL solves complex problems that present critical challenges to the nation. The Laboratory has been a major asset to the nation since it was organized to help the war effort in 1942, four months after Pearl Harbor. APL's first mission was the critical challenge of defending Navy ships from enemy air attacks, by developing an anit-aircraft proximity fuze.
APL also developed the first operational satellite navigation system. To learn about the Applied Physics Laboratory's contributions to the development of GPS, please visit APL Invented Satellite Navigation and TRANSIT aka NAVSAT.
This cache celebrates APL's contributions to satellite navigation, which is based in part on the Doppler shift principle.
So, we've created a quiz based on that principle to help you determine the coordinates of the cache, which is located at N39° 09.XXX and W076° 51.YYY.
For this quiz, assume the speed of sound is 761 mph, and round the final number to the nearest whole number of Hertz.
A fire truck is hustling to a fire at 118 mph, its siren emitting a 458 Hertz tone.
If the fire truck is driving directly toward you, at what frequency do you perceive the siren? (The solution is XXX).
When the fire truck safely passes you, he decides to speed up to 171 mph.
As the fire truck is driving directly away from you, at what frequency do you perceive the siren? (The solution is YYY).
458 Hertz sounds like WUUUUUUUUUUUUU :) Good luck!
You can check your answers for this puzzle on Geochecker.com.
UPDATE: The original cache went missing and the original GZ area didn't have very much for a hide, so GZ was moved a little bit. The new cache should be very secure and the scenery quite nice. After you've solved the puzzle, perform the following:
Add 00.022 to the North coord
Add 00.001 to the West coord
This should take you to the new GZ about 130 feet away.