Evaluation of Verizon Wireless Tower Proposal for Waterbury Prepared for the Vermont Department of Public Service by Fred Goldstein, Interisle Consulting Group, December 2015

Verizon Wireless has proposed building a 93’ tower to be located on the Waterbury-Stowe border, on a property near Ruby Raymond Road. In accordance with Vermont requirements, I have evaluated the application to determine if the proposed coverage appears to be correct, if alternatives on existing towers are available, and if a tower of lower height would be sufficient.

Review of Verizon Wireless Proposed Coverage The proposed site is at 44.41881 North and -72.70464 West. It is approximately 489 meters above mean sea level, and approximately 11 meters lower than the top of North Hill, immediately to its north in Stowe. The height was selected based on Verizon’s determination that it would provide sufficient clearance to the tree canopy to the south and west (facing Waterbury); it does not appear to clear the tree canopy to the north, facing Stowe Village.

I plotted coverage from this site for both the 700 MHz band (used by Verizon for LTE) and the 2100 MHz AWS band. The 700 MHz band, like the 850 MHz cellular band used by Verizon on the WDEV tower in Waterbury, is much less sensitive to tree attenuation than the AWS and PCS frequencies in the 1700-2100 MHz range. The primary factor in coverage is thus terrain, not distance (free space path loss) or clutter (ground cover, such as trees and buildings). While Verizon uses RSRP (an LTE-specific measurement of reference-signal received power) and my propagation prediction modeling tool only used the more generic received signal strength indication (RSSI), the distinction is not critical, especially, as here, in areas of relatively low interference.

My coverage prediction fundamentally confirms the validity of Verizon’s Proposed LTE Coverage map. I have attached a coverage map as Exhibit FG-1. This assumes uniform 360 degree coverage, and does not take into account minor differences in signal strength that might result depending upon the positioning of the proposed sector antennas. I have also attached as Exhibit FG-2 a coverage map based on the 1700-2100 MHz AWS/PCS frequency range. Coverage is similar but with somewhat larger gaps, as these higher frequencies do not perform as well over non-line-of-sight paths.

Purpose and reasonableness of proposal

Verizon selected this location because it fills in a gap in LTE coverage in northern Waterbury, and permits them to “split the cell”, reducing the coverage areas of existing LTE sites in Duxbury and Underhill. The Duxbury tower (referred to by Verizon as the Waterbury Relief site), just south of Waterbury, provides good coverage of much of Waterbury, including Waterbury Center, though not the northern end of the Rt. 100 corridor. However, it is a high site that is running out of capacity. The cellular concept is based on splitting cells when capacity runs low, with newer cells having smaller geographic areas. While the proposed site is at almost the same height as the Duxbury cell, the cells will presumably divide the traffic load between them. Verizon will then lower the downtilt of the Duxbury antenna that faces downtown Waterbury (near I-91), reducing its coverage range, and the new cell would become the primary source of coverage from Waterbury Center to Moscow. Exhibit FG-3 is a coverage map showing the combined 700 MHz LTE coverage of the existing Waterbury Relief tower in Duxbury with the proposed tower, not factoring in downtilt.

The Underhill location is near the summit of Mount Mansfield. At approximately 1210 meters above sea level, its line of sight is so large that it receives excessive interference. Such high sites are not generally used for cellular systems, though they may be useful, at least temporarily, for providing a first service

across a large rural area. This site does provide LTE coverage to much of Waterbury, but Verizon says they plan to stop using it in that direction due to those issues.

Verizon also maintains a cell site on a WDEV AM radio tower in Waterbury. This is an 850 MHz Cellular site, presumably supporting its legacy 3G CDMA network. It appears to have fairly good coverage of Waterbury, but the tower is nearing 80 years old, was not built to support additional antennas (an AM broadcast tower is the antenna), and is thus not suitable for an additional LTE cell. The CDMA antennas are also not standard sectors, but omnidirectional whip antennas, which have a low wind load compared to any kind of sectorized antenna. This site is likely to be phased out along with legacy CDMA in a few years.

Coverage into Stowe, except for a small area (Moscow) just north of the Waterbury-Stowe town line and west of Rt. 100, is not a goal of the proposed tower. Stowe is served from the Underhill site and the village area, and much of Rt. 100, is also served from an 85 foot tower (Stowe 2) near the wastewater treatment plant. Verizon’s applications did not focus on Stowe. The proposed tower is not quite at the hill top, and thus foliage attenuates but does not completely block its coverage to the north.

Given these circumstances, the proposed tower does seem to serve a useful purpose in improving Verizon’s coverage and increasing their capacity (especially for data traffic), and their proposal, including its predicted coverage map, appears to be reasonable.

Alternative sites For a site to be a reasonable alternative, it should provide coverage to the bulk of areas that the proposed site will serve, and should not be unduly difficult to utilize. I have examined several suggested alternatives. However, other than the status quo sites in Duxbury and Underhill, none are known to have an existing structure capable of providing service to much of Waterbury. Thus they are evaluated with the assumption that a new tower could be built at those sites.

Sites on Blush Hill Road, Lonesome Trail and Rt. 2 were not considered as serious contenders. All three are in the southern part of Waterbury, relatively near the Duxbury tower, and thus do not provide new coverage in the northern part of Waterbury and Moscow where the proposed tower would add service. Nor would they be well suited for cell splitting.

Status Quo options

With no additional sites, the Duxbury tower will continue to provide service to much of Waterbury, but some areas in the northern part of the town may lose the coverage they now get from Underhill, and growing congestion will worsen data speeds. Stowe 2 covers the Route 100 corridor from approximately the Waterbury-Stowe line northward but has negligible coverage elsewhere. Thus the status quo would impact service adversely.

Ripley Road

A suggested alternative site is at 1287 Ripley Road, Waterbury, east of Waterbury Center, where a two-way radio tower now exists. This tower is not listed in the FCC Tower Registration database, as it is apparently not tall enough to require it. Nor has it been determined that the existing tower would be able to support Verizon’s antennas. Exhibit FG-4 illustrates the coverage from Duxbury and Ripley Road, based on having a 28-meter tower at the latter site. Exhibit FG-5 illustrates its coverage alone. Coverage is considerably less than complete in Waterbury. It has large gaps along Rt. 100 in the northern part of town, and no coverage of Moscow, but would provide limited relief to the Duxbury cell around Waterbury Center.

Woodard Farm Rd. Another suggested alternative site is 24 Woodard Farm Rd., where the FAA formerly used a utility pole for an air traffic control facility. This site, east of Waterbury Center, is lower than Ripley Road and its coverage would be similarly spotty, providing little fill-in along the northern part of Rt. 100 in Waterbury and no coverage of Moscow, though it would provide some relief around Waterbury Center. Exhibit FG-6 illustrates its coverage. Exhibit FG-7 illustrates combined coverage from Woodard Farm Rd. and Duxbury.

Barnes Hill Road

The Village of Waterbury has a water treatment plant at 556 Barnes Hill Road, with a small existing tower serving municipal purposes that is probably not adequate for Verizon’s use. This site is on a hillside north of Waterbury Center, downhill from the proposed Ruby Raymond Road tower site. Even if a new 28 meter tower were built on the uphill side of the driveway, the altitude of 307 meters is lower than the Ripley and Woodard sites. Its relative proximity to Rt. 100 makes up for the lack of altitude, compared to those two sites, and it has coverage into Waterbury Center and along much of Rt. 100. However, it still does not cover Rt. 100 nearly as well as the proposed North Hill site, especially north of where Rt. 100 meets Ruby Raymond Road, and it has no coverage into Moscow. Exhibit FG-8 illustrates its likely 700 MHz coverage.

Water Department (watershed) Sites

Four alternative sites were suggested that fall within close proximity of one another. These are not current tower sites. All four are on land owned by the Village of Waterbury Waterworks, and are within the CC Putnam State Forest, on the western slopes of Mt. Hunger. They appear to be part of the watershed that feeds Thatcher Brook, which flows to the Barnes Hill Road water treatment plant. These sites are not on paved roads but are near logging roads. They do not have utilities, so electricity would presumably need to either be generated locally or brought in from Waterworks Road (if that has power) or even farther away. Likewise, there are no poles or conduits for fiber optic backhaul to be brought to the site, so that would need to be brought in from some distance or the site would be limited to using microwave backhaul. Given these issues, the ability to construct a tower at any of these sites would probably be considered speculative at best.

Nonetheless, I have examined all four suggested sites for their potential suitability as replacements for the proposed Ruby Raymond Road site. All four sites are on a mountain range that is higher than the proposed site, and between 3.25 and 3.87 km distant, basically to the east. Of the four sites, the one with the best potential radio propagation to the parts of Waterbury of most interest (Waterbury Center and the Route 100 corridor from there to the Stowe line) is the southernmost, at 44.40273 N -72.66139 W. At approximately 655 meters ASL, it is also the highest of the four, and only several hundred feet north of the Stowe-Waterbury boundary.

Despite its higher altitude, coverage of northern Waterbury from the Waterworks site is not nearly as good as from the proposed site. See Exhibit FG-9 for the coverage from the Waterworks site. The main problem appears to be that smaller hills, including North Hill, where the proposed site is located, create RF shadows to many of the valley areas, including much of Rt. 100 in Waterbury. The higher elevation improves its coverage of distant areas beyond Waterbury Center, but this is not an advantage, as it would invite higher interference. Coverage around Waterbury Center is somewhat less complete than from the lower, but closer, Barnes Hill Road site. Moscow is not covered, though some nearby parts of Stowe, not intended to be reached by this project, do fall into the footprint. The local terrain is primarily north-south mountain ridges, characteristic of the Appalachians. The Waterworks site, however, would be an east-west path from its primary service area, while the North Hill site would be on the first ridge east of Rt. 100 and thus have a clear south to west view towards it.

The northernmost of the four suggested sites, at 640 meters ASL, has considerably inferior coverage along Rt. 100 between Waterbury Center and the Stowe line, compared to the southernmost site. It does, however, provide coverage into Moscow. That alone does not appear, however, to make it suitable for the planned cell split, let alone fill in mobile coverage gaps.

Tower height The proposed tower is 93 feet high, about 18 feet above the tree canopy. Antennas must be above the tree canopy to operate with maximum efficiency. 700 MHz LTE can penetrate some degree of foliage, while AWS/PCS frequencies above 1700 MHz are more sensitive to foliage. Weather effects could also be exaggerated by foliage, for instance by the accumulation of ice or wet snow on trees.

The proposed tower height appears to have a few feet of additional height than absolutely required, which could allow a single additional set of antennas to be placed below the planned ones. Targeted coverage from 5 feet lower should be acceptable. Coverage drops off more rapidly to the north as the antenna height is lowered, as the site is on the southern side of North Hill. Even at the proposed full height, AWS coverage to the north is very limited, and coverage into Moscow is very limited. Forecasting the impact of tower height in this case is more a function of examining the exact terrain and local tree height, vs. the larger terrain features which impact coverage overall.

Lowering the antenna 1.5 meters appears to lower the 700 MHz predicted signal strength by 1.5 dB in Moscow, but only 0.2 dB towards Waterbury Center. The AWS signal would be lowered 1.6 dB in Moscow, where it is already unlikely to be usable, and by 0.4 dB in Waterbury Center. The greater height sensitivity towards Moscow suggests that the path is already somewhat obstructed. Thus it can be concluded that while the tower is not the lowest possible height, its height provides only a modest, prudent margin for growth.

Recommendation The proposed tower on North Hill off Ruby Raymond Road in Waterbury will serve a useful purpose, in improving coverage to the Route 100 corridor near the Waterbury-Stowe line, improving coverage into the Moscow section of Stowe, and enabling the current Waterbury Relief antenna in Duxbury to be downtilted. The new site would then serve Waterbury Center while the existing one would focus on downtown Waterbury and the Rt. 89 corridor. Overall LTE capacity would be increased and Verizon Wireless would eventually be able to phase out the vertical antennas now on a WDEV tower.

No alternative sites have been proposed that are known to currently have adequate towers and are geographically suitable. Several sites have instead been evaluated where either smaller towers exist, or where towers could be built. None of these meet all of the goals of the proposed tower. The Barnes Hill Road site appears to come closest, assuming an adequate tower could be built there.

I thus recommend that this project be deemed to meet the radio-frequency-related requirements for a new tower.

Figure FG- 1. Predicted 700 MHz LTE coverage from the proposed Ruby Raymond Road site.

Waterbury Center

Moscow

Figure FG- 2. Predicted 2100 MHz AWS coverage from the proposed Ruby Raymond Road site.

Waterbury Center

Moscow

Figure FG- 3. Predicted combined 700 MHz LTE coverage from the existing Waterbury Relief tower in Duxbury and the proposed tower off Ruby Raymond Road.

Waterbury Center

Moscow

Figure FG- 4. Predicted 700 MHz LTE coverage from the Ripley Road site combined with Waterbury Relief (Duxbury). The impact of downtilting Waterbury Relief to reduce its coverage is not shown.

Waterbury Center

Moscow

Figure FG- 5. Predicted 700 MHz LTE coverage from the Ripley Road site alone.

Waterbury Center

Moscow

Figure FG- 6. Predicted 700 MHz LTE coverage from the Woodard Farm Road site.

Waterbury Center

Moscow

Figure FG- 7. Predicted 700 MHz LTE coverage from Woodard Farm Road and Duxbury- Waterbury Relief sites combined.

Waterbury Center

Moscow

Figure FG- 8. Predicted 700 MHz LTE coverage from the Barnes Hill Road site.

Waterbury Center

Moscow

Figure FG- 9. Predicted 700 MHz LTE coverage from the southernmost Waterworks watershed site on Mount Hunger in Stowe.

Waterbury Center

Moscow