GPS Antenna Specifications
Hiprom GPS products use the 3.3V Trimble III GPS Bullet antenna which mounts on a 1˝-14˝ straight thread or a 3/4˝ pipe thread. Electric connector is a TNC
See Antenna DataSheet
The Antenna receives the GPS satellite signals and passes them to the reciver. The GPS signals are spread spectrum signals in the 1575 MHz range and do not penetrate conductive or opaque surfaces. Therefore, the antenna must be located OUTDOORS with a clear 360 degree view of the sky.
- Image 1:
- The antenna is mounted in a downward position causing the GPS module to have no view of the sky. Thus the GPS module can not obtain lock and will not provide GPS time and position.
- Image 2:
- The antenna is mounted in a sideward position causing the GPS module to have a partial view of the sky. Thus the GPS module can only see a few satellites and have difficulty obtaining lock.
- Image 3:
- The antenna is mounted in an upright position in between two buildings which is obstructing a clear view of the sky. Thus the GPS module can only see a few satellites and have difficulty obtaining lock.
- Image 4:
- The antenna is mounted in an upright position with an unobstructed view of the sky. Thus the GPS module can lock onto the maximum amount of satellites to provide accurate GPS time.
Antenna Cable Extensions
If the 15 foot antenna cable that is supplied with the module is not sufficient for correct antenna placement, a longer cable can be used and if necessary an amplifier can be included. The table below list a set of cable solutions for different lengths.
|Part#||Length(feet)||Fly Lead 1||Bulkhead Connector||Main Cable||Amplifier||Fly Lead 2|
- ACK - Antenna Cable Kit
- S-SMA(Male) Straight Connector
- T-TNC(Male) Connector on cables, TNC (Female) on Bulk head and Amplifier
- AMP 30dB - Also available with 220Vac and 24Vdc Supply Voltages. Not Waterproof.
Antenna Cable Attenuation
50 Ohm coax cable should be used. The longer the cable becomes, the more the GPS signal will attenuate. Because of this, the correct type of cable should be used.
The table below gives an indication of the lengths that will be viable depending on which cable type is selected.
It is not recommended that the antenna patch lead exceed a total loss of 10dB at 1.5GHz, as this may increase the time to GPS lock,
or in extreme cases, prevent GPS lock from being achieved at all.
|Good without using Amplifier (Fixed GPS frequency 1.5GHz)|
The following connectors are used for the GPS cable. The SMA connector is used on the module side and the TNC connector on the antenna side.