Spectracom GPS Timing System Accessories
GPS Antenna Overview
Our systems approach offers standard GPS/GNSS antennas and related accessories for its precision timing products with embedded GPS/GNSS receivers.
A typical installation uses an outdoor antenna installation to collect and reliably transmit the RF of the collected signals to the embedded receiver (such as Spectracom's GPS NTP Servers). As a solutions provider, Spectracom offers best-in-class GPS antennas and accessories from 3rd parties into fully qualified and warranted systems. If you have a specific need for your application, we can assist with sourcing and procurement.
The recommended installation includes:
- Outdoor GPS/GNSS antenna (model 8230)
- Surge suppressor for lightning protection (model 8226)
- Low-loss LMR-400 equivalent RF cable to connect the antenna to the surge suppressor and the surge suppressor to the GPS/GNSS receiver (type N)
- Mounting accessories for a roof-top antenna installation
- Indoor GPS/GNSS reception options when an outdoor installation is not practical
- Options for long antenna-to-receiver cable runs (> 400 ft, 125 meters)
8230 GPS/GNSS Antennas and Accessories
The Model 8230 is a high gain (40 dB) GNSS outdoor antenna covering GPS L1, Galileo E1, GLONASS L1, and BeiDou B1 . It uses a three stage low noise amplifier, a mid-section SAW, and a tight pre-filter to protect against saturation by high level sub-harmonics and L-band signals.
- High gain: 40 dB
- Wide band L1 (GPS, Galileo, GLONASS, and BeiDou)
- Powered by 5VDC from the timing receiver
- Compact weather-proof housing (IP67)
- Type N connector
- Mounting accessories are available
Its conical radome is made of high impact UV stabilized polycarbonate to minimize ice, snow and debris build-up. It can be mounted in a 19mm diameter (3/4 inch) through hole or via its L-bracket.
The GPS/GNSS antenna must have an unobstructed line of sight to the sky. Rooftops that are clear of other structures or geographic features overhead, with views to the horizon, generally make good installation locations. Such a clear view allows the antenna to track the maximum number of satellites. Installations with obstructed views may experience reduced reception quality and may not be able to track the maximum number of satellites. When installing a GPS/GNSS antenna, select a site at which the antenna will not become buried in drifting or accumulated snow. It should not be covered by foliage or placed in a position where it could become obstructed. If possible, avoid placing the antenna in close proximity to broadcast antennas.
Antenna Cable & Accessories
Spectracom recommends low loss coaxial cable such as Times Microwave LMR-400 for the antenna cable. The attenuation characteristics of the LMR-400, or equivalent, at the GPS L1 frequency (1575.42 MHz), along with the high gain of the antenna limits the cable length to a maximum of about 125 meters (400 feet). Spectracom offers standard and plenum rated cable assemblies.
For installations where the antenna cable length exceeds 125 meters Spectracom offers a variety of accessories to extend cable lengths including inline pre-amplifiers (Model 8227), fiber optic links and frequency down-up converters. The receiver powers the GPS/GNSS antenna and most accessories. Spectracom recommends installing a lightning protection device in the antenna line to protect the receiver and connected devices. Spectracom offers a Surge Protector, Model 8226, to shunt potentially damaging voltages on the antenna coax to ground.
8230AJ - GPS/GNSS Anti-Jamming Antenna
Open a New Window to Accurate Time for Your Network. with the Model 8230AJ is a high gain (40 dB) GNSS outdoor antenna covering GPS L1, GLONASS L1, BeiDou B1, Galileo E1, and QZSS L1. Similar to our proven Model 8230, it uses a three-stage low noise amplifier, a mid-section SAW, and a tight pre-filter to protect against saturation by high level sub-harmonics and L-band signals.
- High bandwidth to receive GNSS signals:
- GPS L1
- GLONASS L1
- BEIdOU B1
- Galileo E1
- QZSS L1
- Unique conical antenna pattern rejects interference from the horizon
- Drop in replacement for the Model 8230 Outdoor Antenna for use in high interference situations
- Uses the same cabling as the current Model 8230 and mounts to the same pipe supports with a new L bracket.
- Designed for harsh environments (IP67 rated)
- High out-of-band rejection
- One-year limited warranty
Standard or Anti Jam (AJ) Antenna – Which Should I Use?
The standard antenna sees the entire view of sky, equally receiving signals from satellites at the horizon or the zenith and all points in between. However, there is increasing interference in the GNSS L1 band, whether unintentional from other transmitters like communications towers or intentional from illegal “privacy jammers”. The AJ antenna rejects signals for the lower elevation angles – where most of the interference comes from – and only receives signals from the higher elevation angles where the satellites are. Of course, this reduces the number of satellites the receiver will see, but for the timing application, only a few satellites are needed. Moreover, with multi-constellation receivers, there are an increasing number of satellites available. So you get all the performance in timing accuracy you would get with a standard antenna plus 20 dB or more of interference rejection.
8230AJ GPS/GNSS Anti Jam Outdoor Antenna - Data Sheet
Using a Passive Anti-Jam Antenna to Combat GNSS Interference Case StudyUsing a Passive Anti-Jam Antenna to Combat GNSS InterferenceUsing a Passive Anti-Jam Antenna to Combat GNSS Interference - Case Study