TrueTime GPS Antenna Installation Instructions
General Installation Instructions
1) The site contact should first un-pack the Antenna and locate the 12" plastic threaded mounting pipe. This pipe is used to assist in Mast Mounting the Antenna as described below in step 4).
2) When selecting a site for the antenna, one should find an outdoor location which provides full 360-degree visibility of the horizon. In most cases, this means locating the antenna as high as possible. Any obstructions will degrade unit performance by blocking the satellite signal or causing a reflection that cancels some of the signal. Blocked signals can significantly increase the time for satellite acquisition.
3) Assuming the cable has been properly run, a TNC connector should be crimped at the cable end where the Antenna will be stationed.
4) Mast top mounting is the preferred mounting method. The antenna mounting mast should be 2-inch threaded water pipe or conduit. The pipe must be rigid and able to withstand high winds without flexing. Guy wires may be used to stabilize a pipe longer than 10 feet.
4a. Refer to Assembly Drawing 142-400 in this section which shows the size, assembly and mounting of the antenna.
4b. Multipath cancellation is caused by reflected signals which arrive at the antenna out of phase with the direct signal. Reflective interference is most pronounced at low elevation angles from 10 to 20 degrees above the horizon. The height of the mast may be extended to prevent multipath cancellation. The antenna should be at least 1.0 m from any reflecting surface.
5) Once the Mast Mounting has been completed, the coax cable should be run through the threaded piping and terminated on the back of the Antenna.
6) In the case of lightening protection or grounding, a seperate surge suppressor/protector can be utilized by connecting it into the line and terminating to ground. Information on this equipment will be provided if requested.
Verification of Proper Antenna Installation
Verification Instructions
7) In order to verify that the Antenna is working properly after it has been mounted and the cable is connected to the Surveyor machine, the following procedures should be used:
Connect a standard 101-keyboard and monitor to the Surveyor machine and the reboot it by depressing the top LED indicator on the front of the box. After the machine has reset, log into it using the following 'password' and 'username' (Note: If you are unsure about whether the PC is properly installed, please check the Surveyor Installation / Placement section for assistance.)
username: "guest" password: "guest"
This should place you at the standard BSDI Unix prompt in which you should then type in:
"GPSTEST"
If everything is working properly, you should see the following type of display indicating that the Antenna is "OK" and proper satellite reception is being received based on a GPS "Locked" condition
Antenna OK <------------------------(Cable correctly terminated)If you see the above display, Congratulations! Please contact surveyor-admin@advanced.org to begin the process of placing your Surveyor node in our network mesh of measurement machines
8) If in the case the following information is displayed:
Hardware register = 0xFFCCThe cable is not properly terminated either at the PC or Antenna. For the PC connection, please verify the coax connector is firmly attached to the BNC plug labeled "Antenna", and if possible utilize a voltmeter to measure the voltage at the Antenna end of the cable which should be in the range of 4.5 - 12 vdc
When the problem has been rectified, please revisit step 7) to verify proper GPS reception or contact surveyor-admin@advanced.org for additional assistance.