Washington State Department of Natural Resources

Olympia Radio Operations Project 25 Dual Repeater Test Unit - South Mountain
Information uploaded 01-01-2005

As part of DNR Radio Operations ongoing research and development to enhance the agency's Project 25* based analog narrowband / digital capable radio system, Olympia Radio Ops has assembled and installed a specially constructed dual repeater test unit at the South Mountain facility. The repeaters, one Motorola Quantar P-25 and one Daniels P-25, are the backbone for the agency's mountain top radio infrastructure. The radios assembled in the test unit share the same repeater duplexer* and antenna and automatically select the antenna system depending on the need. This test unit will allow us to make critical comparisons between the two repeaters and mobile units of different manufacture under various test conditions in an actual operational environment . Many times, it is difficult or impossible to duplicate this type of analysis at the test bench. Ocassionally, the question arises, "Why is DNR doing this type of testing? Shouldn't this have been done by the manufacturer?" The answer is "Yes, you would like to think the manufacturers have worked out all the problems, but in reality that's just not the case." With the complexity of this leading edge technology and the thousands upon thousands of lines of code written to direct the operation of these microprocessor controlled devices, sometimes flaws or interaction within this programming produce unexpected results in specific operating circumstances. These anomalies uncovered during this type of testing or through actual operation by the end user are sometimes referred to as "undocumented features" of the equipment involved. Once these issues are identified, we will sometimes work with the manufacturer to correct the conditions or develop our own work around to provide reliable operation.

Additional views of the P-25 Test Unit and antenna system can be accessed via the links below.

Another view of the Olympia Radio Ops Project 25 dual repeater test unit

AC power lightning protection - Building internal

Antenna coaxial cable lightning protection - Building internal

Antenna coaxial cable lightning protection - Building external

Antenna installation

*Project 25 (P-25) is an industry wide radio standard that provides a certain degree of compatibility between digital capable radio units of different manufacture.
*A duplexer consists of mechanically tuned resonate cavities that allow a repeater to receive and transmit on the same antenna simultaneously.

Radio Site Staff: Larry Gruber, Parks Radio 10 - Rob Lee, DNR Radio 28 - Andy Osborn, DNR Radio 29

Questions? ... Comments? ... Rob Lee, DNR Radio Operations, Olympia
Information uploaded: 01-01-05