FAQs
Satellite Basics
What is a communications satellite?
A communications satellite is a radio relay station in orbit above the earth that receives, amplifies, and redirects signals carried on a specific radio frequency.
Communications satellites are basically a repeater in the sky – maintained at various heights above the earth.
There are 3 main varieties:
- Low Earth Orbit or LEOs @ between 500 and 2000km above the earth,
- Medium Earth Orbit (MEOs) @ 8000 to 20,000km above the earth and
- Geosynchronous Earth Orbit or GEOs @ approximately 36,000km.
LEOs are primarily used for voice communications and small data transfers and can circle the earth in around 1 and a half hours, requiring handoffs to adjacent satellites. MEOs are typically weather and spy satellites.
Most Commercial Communications satellites are the GEO type. GEOs travel with the earth sitting above the equator in a “stationary” position, able to view approximately 1/3 of the earths surface. Most have beams or footprints allocated to a region with different frequencies and power levels.
What is the architecture of a satellite?
Communications data passes through a satellite using a signal path known as a transponder. Typically satellites have between 24 and 72 transponders. A single transponder is capable of handling up to 155 million bits of information per second. With this immense capacity, today's communication satellites are an ideal medium for transmitting and receiving almost any kind of content - from simple voice or data to the most complex and bandwidth-intensive video, audio and Internet content.
What is Orbital Location?
The location of a geostationary satellite is referred to as its orbital location. International satellites are normally measured in terms of longitudinal degrees East (° E) from the Prime Meridian of 0° (for example, SES World Skies NSS9 satellite is currently located at 183° E).
What is a Footprint?
The geographic area of the Earth's surface over which a satellite can transmit to, or receive from, is called the satellite's "footprint." The footprint can be tailored to include beams with different frequencies and power levels.
What are the Frequency Bands and Beams
Satellites transmit information within radio frequency bands. The frequency bands most used by satellite communications companies are called C-band and the higher Ku-band. Over the next several years, the use of a higher frequency band known as Ka-band is expected to increase. Modern satellites are designed to focus on different ranges of frequency bands and different power levels at particular geographic areas. These focus areas are called beams.
- Global: covering almost 1/3 of Earth's surface
- Hemi: covering almost 1/6 of Earth's surface
- Zone: covering a large landmass area
- Spot: covering a specific geographic area
What is installed on the ground?
All communications with a geostationary satellite require using an earth station or antenna. Earth Stations may be either fixed (installed at a specific location) or mobile for uses such as Satellite News Gathering (SNG) or maritime applications. Antennas range in size, from large telecommunications carrier dishes of 4.5 to 15 meters in diameter, to VSAT antennas which can be as small as under one meter, designed to support services such as Direct to Home TV (DTH) and rural telephony.
The antenna, itself, will generally be connected to equipment indoors called an indoor unit (IDU), which then connects either to the actual communications devices being used, to a Local Area Network (LAN), or to additional terrestrial network infrastructure.
What is a VSAT?
Very-small-aperture terminal (VSAT), is a two-way satellite ground station with a dish antenna that is smaller than 3 meters. The majority of VSAT antennas range from 75 cm to 1.2 m. Data rates typically range from 56 kbit/s up to 4 Mbit/s. VSATs access satellite(s) in geosynchronous orbit to relay data from small remote earth stations (terminals) to other terminals (in mesh topology) or master earth station "hubs" (in star topology). There are three main VSAT Types:
- Fixed
- Semi-Fixed (Non penetrating mounts)
- Mobile – Quick Deploy & FlyAway
Service-Specific
I would like to set-up a satellite internet connection. What do I need?
At its simplest, you require terminal equipment consisting of a 2-way satellite antenna, a modem and a BUC and a bandwidth package of desired contention ratio (the most common ratios are 1:1, 1:4 and 10:10).
For complex, corporate types of networks, contact our sales team.
My satellite link is down. What should I do?
- 1. Check that the hardware is powered on.
- 2. Restart your modem
- 3. Check your account status
- 4. Check for any planned/scheduled outages.
- 5. If all else fails, contact Pactel NOC Support.
Why is my internet slow?
- Disconnect all your PC’s except for one. Test the internet speed – if performing well, you possibly have too much internet traffic passing over the network.
- If disconnecting the PCs have no impact on the internet speed of the remaining one, contact Pactel NOC Support.
What is a sun outage?
A Sun Outage (also known as satellite interference) occurs when the orbital positions of the satellite and the sun are in one line. The earth station receives signals from both, but the more powerful sun rays subdue the desired signal, causing a temporary loss of service. Since Pactel International receive our signals from a variety of satellites, the Solar Outages can occur at different times on different channels. Check the sun outage calculator for information on when the sun outage will affect your service. Pactel’s NOC Support team will send out regular updates on the sun outages affecting their customers’ service.
What is a rain fade?
Rain fade occurs at a Ku-Band frequency and refers to the degradation of a signal caused by the electromagnetic interference of the rain. Rain fade can be caused by precipitation at the uplink or downlink location. However, it does not need to be raining at a location for it to be affected by rain fade, as the signal may pass through precipitation many miles away, especially if the satellite dish has a low look angle. One of the rain fade mitigation techniques used by Pactel is Uplink Power Control – a simple tool that increases the power to compensate for the loss of the signal.