XM-Radio   ( SDARS )

XM-Radio is a Satellite Based Radio Broadcast System that operates around 2.3 GHz from two 15,000 watt satellites; one named "ROCK" (XM-1), at 115 Degrees West, the other named "ROLL" (XM-2), at 85.0 Degrees West.  The original satellites had flawed solar panels, and have since been replaced by "RHYTHM" (XM-4), and "BLUES" (XM-3)

The problem with this service and that of Sirius Radio, a similar satellite radio service, is that that they usually work fine in open areas, but their signals are blocked by tall buildings.  The satellite signals are sometimes totally lost or too weak to decode.  To maintain service under conditions where the satellite signal is too weak, the signal is received at another location and re-transmitted from a transmitter that can cover an entire city. 

To accomplish this,  XM-Radio alone will set up around 1,500 high-power terrestrial (earth based) repeaters. Each market (metropolitan area) will typically have dual repeaters at  2337.485 MHz and 2340.015 MHz.  Some terrestrial (earth) repeaters have an Effective Radiated Power (ERP) of up to 25,000 watts.

A hefty buffer (lots of ram) is an integral part of each receiver, and is very practical when going through tunnels. The service is aimed at the mobile audiophile, who wants 100+ CD Quality Radio Stations in his car.  

The significance to television broadcasters and microwave data users is the high power 2.3 GHz terrestrial repeaters, located in his market, and the affect it will have on 2 and 2.5 GHz receive systems, especially receive sites for live television news.  Most Combination 2 & 2.5GHz Antenna Systems will have little rejection against these high-power repeaters.   

2 & 2.5 Ghz antenna systems built before 1998 for Microwave Radio  (such as the ULTRASCAN, etc, have NO rejection at all, and will amplify these signals. 

If you thought PCS and AWS was bad, wait until this system is fully deployed using high-power repeaters!

Find out more about Sirius or XM Radio

SDARS (Satellite Digital Audio Radio Services)
An SDARS system can provide CD quality audio programming to a broad coverage area. A terrestrial repeater network is required  in a  SDARS system.

 Due to the limitations of satellite transmission, the signal is not able to penetrate buildings, so it cannot effectively cover dense urban areas. The terrestrial repeater network extends SDARS coverage and allows providers to reach the greatest number of subscribers and provide quality coverage.

The radiation in an operational system is similar
to that of a MICROWAVE OVEN!
Avoid the main lobe while servicing equipment on your tower.


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