OpenSky is a digital radio system sold by a division of Harris (formerly a division of M/A-COM). It was introduced in 1999 as an expansion of the Monarch wireless voice and data system built for FedEx.

OpenSky uses a four-slot TDMA transmission method (four-level GMSK modulation) in 25 kHz bandwidth channels with an aggregate data rate of 19.2 kbps (symbol rate of 9600 baud). This is on both the forward and reverse links.

There are three primary OpenSky protocols: FMP (Federal Express Mobile Protocol), OCP (OpenSky Communication Protocol), and OTP (OpenSky Trunking Protocol). FMP supports digital voice. The airlink protocols are based on modified Cellular Digital Packet Data (CDPD) IS-732 and carry voice using DVSI's AMBE (Advanced MultiBand Excitation) vocoder. M/A-COM modified the physical layer and Media Access layers to support trunking and mixed voice and data traffic.

Note that the older ProVoice on EDACS uses GFSK at 9.6 kbps and the IMBE vocoder.

Updates on the following reported OpenSky systems are encouraged.
Please send additions, corrections and updates to Dan.

State Location Contract
Go Live
Status Comments
Arizona Central Arizona Project 2008     Upgrade existing EDACS
7 sites
narrowband (12.5 kHz) channels
1,400 users

As of 2010, CAP operated from "ten mountaintops and several cell sites" that provide "good coverage along the entire length of the project from Lake Havasu to Tucson."

However, a 2012 request to the FCC to renew a Special Temporary Authority (STA) includes this:
"This STA has been necessitated by gaps in radio coverage at critical locations along the CAWCD canal in Arizona, including pumping stations."

California Orange County 1998     Orange County Transit Authority (OCTA)
California Sacramento and Placer Counties December 2005 Cancelled Not accepted; implementation cancelled Sacramento Municipal Utility District (SMUD)

900 square mile service area; 550,000 customers
Voice and Data in 900 MHz, two-slot TDMA with 12.5 kHz channels

More than $6 million spent.

Reportedly, the contract was terminated in 2009 with an undisclosed settlement and a one-year non-disclosure agreement (which has now expired).

SMUD is using a new Motorola system.

Connecticut statewide 2013     Northeast Utilities

Operates in the 900 MHz band
(935 to 939 MHz)

Florida Palm Beach County April 2001 April 15, 2010 Partially operational Municipal Public Safety Communications Consortium (MPSCC)
  • Town of Palm Beach
  • City of Palm Beach Gardens
  • City of West Palm Beach
  • Village of Atlantis
  • Town of Jupiter
  • Town of Juno Beach

Phase 1 to use five repeater sites
$18 million

Palm Beach Police Department has been on the system full-time since April 15, 2010.

As of June 2010, Palm Beach Gardens and the Town of Palm Beach are on the system.

The West Palm Beach Fire Department determined that OpenSky had not been used successfully in any fire department in the country.

Jupiter went live on the system on May 5, 2011.

As of June 2011, West Palm Beach has spent $3.6 million on equipment and $465,000 in maintenance. The city is awaiting final approval to purchase 400 radios for $1.6 million.

Jupiter Police Department transitioned to OpenSky on May 14, 2012.

Georgia Jackson       EMC
Georgia Jackson County       Water Authority
Georgia Macon November 2012     $8 million contract

Three-site P25 system with an OpenSky "overlay" for data

Georgia Marietta        
Georgia Newton County 2006 October
Operational $4.5 million
7 repeater sites
575 users (initial)
1,300+ users (expansion)

Additional repeater site added in 2011

Illinois Cities of Aurora and Naperville 2008 December 1, 2010 Operational Aurora: $15.9 million
Naperville: $10.1 million

Press reports indicate the system has experienced almost 800 malfunctions between December 2010 to March 2011.

Illinois Peoria County December 2007   Never Built $11.2 million
Contract signed with M/A-COM in December 2007 with an expected go-live date of June 2010.

From the July 10, 2013 meeting minutes of the Peoria County Emergency Telephone System Board (ETSB):

In 2005, the ETSB went out for bid for a Countywide radio system. At the time, a proposal was submitted for a P25 Digital Radio System by another vendor at a cost of approximately $30 million dollars. Due to financial limitations and the competitive bid process, it was decided that the Open Sky system, for approximately $11.3 million, would suit the needs of Peoria County. Due to the inability of Peoria County to secure the number of radio frequencies required for the Open Sky system, and a clause in the original contract specific to that, the ETSB was able to negotiate a change in technology with our vendor, Harris Corporation, from the Open Sky system to a P25 Simulcast Radio System for the same contract price of $11.3 million. It took much due diligence on the part of the ETSB, and specifically the ETSB Technical Committee, to negotiate that contract Change Order. Ultimately, Peoria County is getting a more sophisticated and dependable radio system for the same contract price.

Indiana Steuben County May 2007 January 12, 2011 Users reported No Confidence in April 2011

Replaced by a P25 system

$5.6 million
Eight channels, six repeater sites, 800 MHz

System went live January 12, 2011.

Experienced a total failure on April 5, 2011. County Sheriff issued a statement of "No Confidence" and ordered a return to the old EDACS network while the County Commissioners explore options.

County is building a P25 Phase 2 system to join the Hoosier SAFE-T system and will abandon the OpenSky equipment. New system is expected to go on line in Summer 2017.

Indiana Merrillville     Reportedly operational Northern Indiana Public Service Company (NIPSCO)
Report of sites going in to Baily and Michigan City power plants.
These are two channel, four slot sites.
Michigan Detroit 2002   Apparently operational
(No local reports)
Detroit Department of Transportation (DDOT)
Single-site UHF (possibly call sign KZI382) for buses
Michigan Oakland County February 2002   In the process of being replaced by a P25 system $33 million
Connect more than 80 agencies; 6,000 users
Courts and Law Enforcement Management Information System (CLEMIS)

Originally slated for completion in late 2004.
As of August 2008, operating in Troy, Farmington and Clawson.

Final system to use more than 40 frequencies; 35 repeater sites

As of June 2019, Oakland County has contracted with Motorola to replace the 15-year-old OpenSky system with a P25 Phase II network and interconnect it with the statewide Michigan Public Safety Communication System (MPSCS).

The upgrade may take three years to build out the 31-site simulcast system.

Mobile Radios: 1,861
Portable Radios: 4,343

Nevada Clark County        
Nevada Las Vegas February 2006 January 2011 Reported as unacceptable in October 2012

Replaced by a P25 system

Serves Las Vegas Metropolitan Police Department (LVMPD)

Original (2006) contract cost of $8.9 million

As of 2011, the "DesertSky" system uses 28 repeater sites and claims to support more than 12,000 users.

In August 2011, reports of audio quality problems.

In October 2012, LVMPD officially informs Harris that the "Desert Sky" system cannot meet department needs, after an expenditure of $42 million.

New Jersey statewide     initiative in 2006 New Jersey Transit
New York Statewide 2004 Cancelled Contract terminated
January 2009
$2 billion
Oklahoma Broken Arrow       Three sites licensed: two in Broken Arrow and one in Jenks.

Frequencies: [Broken Arrow (Kenosha Street)] 854.0375, 854.1625, 854.3625, 854.4125, 854.4375, 856.7875, 856.8375, 857.7875, 857.8375, 858.7875, 858.8375, 859.7875

[Mobile] 854.0375, 854.1375, 854.1625, 854.1875, 854.2125, 854.3125, 854.3625, 854.4125, 854.4375, 854.4875

[Jenks] 856.2625, 857.2625, 858.2625, 859.2625

[Broken Arrow (South Hickory)] 854.1375, 854.1875, 854.2125, 854.3125, 854.4875

Equipment installed in 2010 into police, fire and emergency medical service vehicles. Includes mobile data connectivity.

Pennsylvania Allegheny County August 2004      
Pennsylvania Cumberland County August 2000   Operational Poor or no signals in some areas
Pennsylvania Lancaster County December 2000 Cancelled Contract terminated
March 2008
Originally a $35 million system
Spent $13.8 million
Pennsylvania Statewide 1999   Replaced with P25 Phase 2 network

State spent an estimated $850 million on the OpenSky system until giving up in 2016.

In April 2011, State Police report an average of 161 service outages each month.
Annual operating cost of $22 million

Original plan for statewide coverage called for 268 repeater sites. As of April 2010 the State has deployed over 800 sites in an attempt to provide adequate coverage.

$368 million spent as of June 2008 ($179 million appropriated by the State in 1996 plus an additional $189 million appropriation)

Texas Dallas May 2009   Proposed Dallas Area Rapid Transit (DART)
3,000 radios
existing DART 800 and 900 MHz frequencies
Texas Houston   February 2010 Operational Continental Airlines at George Bush Intercontinental Airport
Texas Houston August 2010   Contract Award CenterPoint Energy

Will replace the current analog trunked radio system and a Data Radio UHF system.

Special Temporary Authority (STA) granted as call sign WQOU588 in February 2012, due to expire at the end of July. The STA covers operation from three sites, located in Houston, Waller and Pinehurst, transmitting on 859.8625, 855.1625, and 859.3375 MHz.

Texas Lower Colorado River Authority   2011 Operational 900 MHz system
Service area covers 50,000 square miles, "abutting Mason to the west, Houston to the east, Temple to the north, and San Antonio to the south."

January 10, 2011:

LCRA is currently in the process of migrating from its current Enhanced Digital Access Communications System (EDACS) to a new "OpenSky" wireless communication system. OpenSky is a Harris digital radio technology that will be used for LCRA’s next generation radio system. LCRA’s migration to OpenSky will utilize the 900 MHz frequencies covered by LCRA’s extended implem entation plan. Both site infrastructure and terminal radio equipment for LCRA’s existing EDACS radio system are no longer being manufactured for this aging technology. Furthermore, support for this older EDACS system is becoming more difficult as the expertise is being directed toward the newer technology. Nevertheless, approximately 8200 of LCRA’s internal and external customers depend on the EDACS system for their daily operations. As such, LCRA will continue to work with its customers to provide a migration strategy that is both economically and operationally feasible.

LCRA will continue to operate in the 900 MHz spectrum with OpenSky, thus allowing the reuse of existing antenna systems, site infrastructure and available channels. The radio migration is phased in a five year implementation schedule to allow for the hardware replacement of 56 sites and adequate testing during each phase. The phased migration is also necessary for LCRA to coordinate both internal and external resources. It is essential that LCRA phases its radio migration to allow its customers to adequately plan their transitions.

May 9, 2018:

Due to benefits related to cost and coverage, Fayette County focused in the past on adopting the 900 MHz Opensky system as the standard for their emergency responders. After several years, it has become clear that the lack of interoperability of the 900 MHz system with surrounding P25 compliant systems is causing significant challenges related to intra-county and regional interoperability.

LCRA Fiscal Year 2019 Business and Capital Plans

Radio System Migration – FY 2019 Telecommunications Upgrade – The project will upgrade firmware in approximately 3,200 OpenSky radios to allow for conversion to the P25 network commonly used by emergency response organization dispatchers. The upgrade is based on vendor recommendations and notifications regarding termination of OpenSky support for the radio system
Washington, D.C. area Washington Gas August 2009   Contract award 20-site, 900 MHz
two-slot TDMA in 12.5 kHz channels

Washington D.C., Maryland and Virginia

A November 2012 press release indicates the system now uses OpenSky2 technology, has 22 sites for 900 MHz OpenSky operation, and operates the P25 system in West Virginia as well.

Wisconsin Ozaukee County     Operational Data-only

Meeting minutes in 2004 indicate the county stayed with EDACS rather than go to OpenSky due to "problems with voice over IP" and "Open Sky is still good for data, but still not up to speed with voice."

Wisconsin Milwaukee 2003 September 2010 Police operational as of February 2010

Data services working for Police and Fire

Local reports of police cars and officers equipped with OpenSky radios as of Summer 2009

Media reports indicate it was fully operational as of September 2010, although system-wide failures continue to occur (October 7, 2010, for at least 30 minutes).

Cost: $15 million

Planned project phases:

  1. Data services
  2. Police
  3. Fire and EMS
  4. Health and Public Works

Missed deadlines:

  • November 2005
  • January 2006
  • June 2006
  • August 2007

Allegations include:

  • Sufficient capacity for the city on the county trunked system
  • Motorola withdrew from the bidding process, claiming it was rigged for M/A-COM
  • The city did not hire an outside radio consultant; the specifications and Request for Proposals came from city committee
Various FedEx       19 regional systems linked together

1936 General Electric Mobile Radio Division formed
August 1950 Microwave Associates, Inc. starts in Boston, Massachusetts
1978 Microwave Associates, Inc. changes name to M/A-COM, Inc.
August 1989 General Electric and Ericsson form Ericsson-GE Mobile Communications, Inc.
May 1998 Ericsson purchases General Electric's remaining 40% interest in Ericsson-GE
June 1995 AMP, Inc. acquires M/A-COM for $277 million
April 1999 Tyco Electronics acquires AMP, Inc.
January 2000 Ericsson sells the Private Radio Systems unit to Com-Net Critical Communications, creating Com-Net Ericsson Critical Radio Systems
May 2001 Tyco International acquires Com-Net Ericsson and merges it into its M/A-COM divison
June 2007 Tyco International splits into three operating companies, one of which is Tyco Electronics Ltd. M/A-COM is part of Tyco Electronics' Wireless Systems Segment.
April 2009 Tyco Electronics announces the sale of the Wireless Systems Segment to Harris for $675 million, who will combine it with Harris RF Communications. The new business unit will be called "Public Safety and Professional Communications."

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Last updated January 24, 2023