Washington State Department of Natural Resources

Questions? ... Comments? ... Rob Lee, DNR Radio Operations, Olympia

South Mountain - Shelton Repeater Site
Before and After Building Interior Images

Before 8-7-2003
Old radio equipment located in beige cabinet style enclosure at far end of row.

Shown at the left is a front view of the 10-21-03 equipment configuration at South Mountain including the latest battery back-up design housed on the aluminum shelf attached to lower portion of the gray equipment rack. Above, in that same rack, is the Shelton Motorola Quantar repeater (black unit). Just below the Quantar is the accompanying transmitter - receiver duplexer (business cards attached).



On the right is a 10-21-03 rear view of the equipment configuration showing the addition of a wall mounted Motorola cavity filter. The large gray mechanical filter is used to narrow the amount radio spectrum that the repeater receiver is able to see in addition to what is afforded by the transmitter-receiver duplexer. The cavity filter may also be referred to as a bandpass filter as it allows only a small segment of the frequency band to be passed on to the receiver without attenuation. Use of the filter will help reduce adjacent channel interference which sometimes can be a problem at mountain top sites with a multitude of radio transmitters.



Mountain top radio sites are very vulnerable to lightning strikes. One responsibility of the DNR radio technician is to insure the site equipment installation adheres to lightning protection as outlined in Motorola R-56 Standards and Guidelines for Communications Sites. The arrow on the image to the left points to one of many critical aspects of grounding at a radio site. When this lightning suppression device is properly installed in the antenna coaxial cable, it will help dissipate lightning energy into the site ground system rather than dissipating the energy in the radio equipment.

South Mountain - Current Status Highlights (Interior) 10-21-2003



Removal of old radio equipment mounted in cabinet style enclosure and installation of new radio equipment in a floor mounted equipment rack. Upper rack secured to existing cable runway to aid in seismic protection.

Rework of communications shelter equipment grounding system and relocation of lightning suppression to shelter coaxial cable entrance panel to meet Motorola R-56 communications site standards.

Addition of a battery back-up system to aid in making any commercial power to generator power transitions appear transparent. Battery back-up will also provide a limited amount of repeater operation in the event of loss of both commercial and generator power.

Rework of initial battery back-up design incorporating a battery enclosure. First design did not include an enclosure.

Addition of receiver bandpass filter.

Computer programming of site equipment at the time of transition to the new narrowband analog - digital capable system.

Posting of FCC license.

Questions? ... Comments? ... Rob Lee, DNR Radio Operations, Olympia
Information updated: 01-16-05