Coverage Maps Topics
Satellite coverage maps are also known as footprints. Though not precise, they provide a visual indication of where you can get service and what size dish you should have.
Shown above is an illustration of the Echostar 17 satellite.
Satellite coverage maps indicate power output from each satellite, listed in dBW. Power roughly doubles, with each 3 dBW change. So, for example, if you are somewhere that is 50 dBW, and you move to a location where it is 47 dBW, your equipment will receive about half the power.
A problem with footprint maps is that they are inexact in several ways:
- Nobody has gone to all of the locations and actually measured signal strength.
- No two transponders on a given satellite have the exact same output, so the map is, at best, an average.
- There are coverage "holes" associated with all satellites and they have also not been precisely mapped.
Signal strength refers to the strength of the signal produced by a radio transmitter at a particular location. It is usually expressed as microvolts or millivolts per meter of effective receiving antenna height. Signal quality includes signal strength, but it also factors in the signal-to-noise ratio (SNR), the bit error rate, and channel multi-path distortion.
If a Ku-band map shows a location at 49 dBW, it will almost certainly work with the standard satellite Internet dish (.74 or .75 meter). At 44 dBW, it probably won't work. Everything in-between is a “maybe”.
A signal strength of 46 dBW or greater is considered acceptable for use of the standard-size dishes. Based on relative reflective surface area, the equivalent signal should be achieved at about 44 dBW with a .98 meter dish and at 42 dBW with a 1.2 meter dish.
When the lines are close together, similar to on a topology map, the signal strength drops off dramatically and quickly. This is called the cliff effect.
The satellites used by HughesNet for Ka-band consumer services are shown below.
|Echostar XVII||E17||107.1 W||Speeds up to 15 Mbps down|
|Spaceway 3||E9||95 W||Speeds up to 5 Mbps down|
The primary satellite used by HughesNet is Echostar 17. It is also called Jupiter, because of the JUPITER high-throughput technology it uses. It was successfully launched on July 5, 2012 by Arianespace and is in its permanent geosynchronous orbital slot of 107.1° West longitude.
The Spaceway 3 satellite is the first Ka-band satellite launched by Hughes. It was built by Boeing Satellite Systems International, Inc. and successfully launched on August 14, 2007 by Arianespace. Spaceway 3 is in its permanent geosynchronous orbital slot of 95° West longitude. The Spaceway 3 system was designed and developed by Hughes as a next-generation, Ka-band broadband satellite system. It was the world's first commercial satellite to employ on-board traffic switching and routing capability.
When Hughes launches a third satellite next year, the higher speed Jupiter services will be available anywhere in the lower 48 states, and elsewhere!
Shown below is the approximate coverage for the Echostar 17 and Spaceway 3 satellites:
There are Ku-band coverage maps available for many satellites in the satellite maps folder.