"Smarter Timing Solutions"
Window-Mount GPS Antenna
The best place to mount a GPS antenna is outside, with an unobstructed view-of-the-sky. However, an inside
window-mount antenna can also work. Following are instructions for determining if your window location is
adequate. Window-mounting guidelines are on the reverse.
Check Your Window
1. Make sure no obstructions: Your antenna works best if it has a big view of the sky.
Look out the window in question. Are there high-rise buildings or large trees close by? Anything
blocking the view of the sky is a possible problem.
2. Avoid metallic film coating: Many windows have a coating on them that you cannot see.
This will prevent your GPS antenna from working. If you happen to have a handheld GPS Position-
ing Receiver then see if it will work next to the window. If it doesn’t, then there may be a metallic
film on the window and your EndRun GPS Antenna will not work either. If it does work, then that
proves the window has no metallic film.
3. Face in the best direction: If you are near the equator then your window can face in
any direction. However, the further you are from the equator, then the more the direction of your
window matters. So, if you are far from the equator and in the Northern hemisphere, then a south-
facing window is best and in the Southern hemisphere, the opposite is true.
Temporarily Mount the Antenna
Place the antenna somewhere in or very near your chosen window. Connect the cable to the
antenna and the Sonoma. Be sure to not kink or bend the cable too tightly.
Get a Position
Your Sonoma needs to calculate its position in order to operate properly. It only needs to do this
once, but it requires that four satellites are visible. If your Sonoma has a limited view of the sky, it
may not be able to see that many satellites, so you will need to manually enter your position. See
Appendix E - GPS Reference Position in your Sonoma User Manual for instructions.
Validate Operation
If your Sonoma was able to calculate a position on its own, then this window is a good location
for the GPS Antenna. Proceed to permanently mount the antenna in this window. If you had to
manually enter your position, then wait for Sonoma to indicate that it has acquired time and is locked. This should take less than 15 minutes. If it
does not lock, then call or email EndRun Customer Support for assistance.
Permanently Mount the Antenna
See the reverse for detailed instructions on how to window-mount your antenna.
Improve Reliability
Because of the reduced sky visibility that is typical of a window-mount installation, your Sonoma may go through many hours without locking to a GPS
signal. This is fine - as long as it locks at least once every 24 hours. If it goes longer than 24 hours without locking, then it will stop serving Stratum
1 time. The optional OCXO upgrade will allow your Sonoma to serve Stratum 1 time for 35 days without receiving a GPS signal. An OCXO upgrade is
extra insurance for window-mount installations.
GPS ANTENNA INSTALLATION GUIDE
INSTALLATION GUIDE
