2018 Restoration of Big Black Mountain HPWREN and ALERTSDGE Instrumentation and Radio Relay Site

January 8, 2019

Black Mountain is a summit in the Cleveland National Forest of the Peninsular Ranges in eastern San Diego County, California, north of Ramona. It has been a key observation, relay and meteorological site for HPWREN since its early 2013 installation. The peak is measured at 4,048 feet (1,234 m), and is sometimes referenced as Big Black Mountain to distinguish it from the smaller Rancho Peñasquitos Black Mountain Open Space Park in the city of San Diego (west of I-15). Black Mountain is also home to one of the largest remaining tracts of the threatened Engelmann Oak (Quercus engelmannii).

On January 28, 2018 a significant Santa Ana wind condition impacted San Diego County, and with it came substantial damage at about 10:08 AM to the Big Black Mountain relay site north of Ramona. The relay site supported a link to the HPWREN backbone site on Mount Woodson, and connected a firefighting agency site. A set of four Mobotix 360 degree cameras, the ALERTSDGE Axis PTZ camera, and a Vaisala meteorological sensor suite were also mounted to the tower at this solar-powered relay site. 80-90 mile per hour winds were recorded in this area prior to the damage ( http://hpwren.ucsd.edu/news/20180218/), which dislodged and bent a communication tower section, tore out its base mount, and destroyed numerous cable runs.

Damage to the tower by strong winds on January 28, 2018.

The site was completely rebuilt and restored to operations over the remainder of the year by the HPWREN team. Damaged materials were removed, assessed and the field site system design was reviewed and redesigned accordingly to help mitigate future weather events. Some key components required custom design and fabrication, new equipment was ordered and configured, the resulting system was bench tested in the lab, transported to the site and reinstalled. Site improvements included customized reinforced and weatherized dual camera housings, reinforced tower mounts, and the additions of a router and backup communications link to provide redundant connectivity.

Custom design of the restored and improved relay site.

Site access required significant off-road truck trail traversal as well as a quarter mile final wild-land hike in to get to the peak, all of which presented challenges to these efforts (consider carrying by hand awkward tower segments, a generator, solar panels, and heavy deep cycle battery banks on a quarter mile back country hike). Work, which included numerous site visits, had to be scheduled around the often challenging site weather conditions and regional red flag (elevated fire risk) warnings.

Installation of the web cameras.