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/Imvaii Preliminary Technical Assessmen! /CTAP-/IUHA-PREASSESS-001-RO The enclosed herein provides information relative to the expansion of the current island wide microwave system. The system is comprised of 8 GHz, 11 GHz and 18 GHz paths. There are a total of seventeen additional paths in the network. Of that seventeen, two have concerns relative to path blockage. They are the paths to COC Road and Waipio Valley. Since there appears to be no line of sight to these locations from any existing island radio sites the recommendation would be to pursue an option of using a product that does not require line of sight (i.e. 4.9 GHz Orthogon) or to go with a leased telephone circuit. This comment about the 4.9 GHz Orthogon product capabilities is not true. The product is advertised as not requiring Line of Site (LOS) but it does not overcome blocked paths. What is referred to as normal LOS in microwave radios is the center line of the signal plus a minimum of 0.60% of the first Fresnel zone. The manufacturer of this product states that the product can overcome obstructions of the Fresnel zone but not complete blockage. The two (2) paths mentioned above are completely blocked and if, after re-evaluating the site selection process these sites are still required, then other connectivity will be necessary. For simplicity of system maintenance, we recommend that the microwave system be designed with a common radio platform that can operate in 6 GHz for long haul paths and 11 GHz for short (under 10 miles) paths. There is a minimum antenna size limit that the FCC places on certain microwave frequency bands. To meet FCC Regulatory compliance for the 6 GHz frequency bands, the minimum dish size allowed is six (6) foot diameter. The 11 GHz band has commercially available antennas that meet the FCC regulatory compliance with antennas as small as three (3) foot diameter. If the new paths for this design are considered short enough to consider the 11 GHz option then any potential tower leases for the new sites can be considerably lower. ICTAP prefers to minimize any recurring costs on any agency owned systems. Another potential advantage to the smaller antennas is the aesthetic impact on buildings and facilities plus minimal physical impact on tower structures allowing more closely installed antennas and less adverse wind loading on a structural analysis. 5. High Performance Data (HPD) It should be noted that HPD is a Motorola proprietary product. Hawaii should anticipate that Motorola may be the only vendor to offer additional equipment or upgrades for this product for the life time of the product. The product is, and may be, sole sourced and specifying it would likely impact the potential competition for the voice system as well. There are several alternatives to HPD such as CalAmp's DataRadio, IPMobileNet's products, GE MDS products and M/A-COM's Opensky data product. ICTAP recommends that the County specify the performance that is required from a data system and not specify particular products in their procurement process. Unlike voice, there are no standardized methods for predicting RF propagation (coverage) of data communications for public safety communications. Therefore it is currently not possible to calculate coverage predictions of HPD in a standardized process. Predictions are dependent on a vendor's recommendations of the parameters to be used to analyze their system. Motorola has stated publicly that the coverage of HPD at the 96 kb/s rate is approximately equal to that of voice. Therefore, ICTAP expected to see that the coverage of voice to a vehicular unit and the coverage of HPD to that same vehicular unit would be approximately the same. The predictions in the Conceptual Design Report in section 3.4 state that mobile (vehicular) voice covers 85.9% of the County using 26 sites whereas HPD covers 98.2% of the County (more than voice) using only 17 sites and one of these is located on Maui. Based on Motorola's statement that coverage is the same and based on ICTAP's knowledge of the propagation characteristics we find this discrepancy between voice and HPD coverage to be problematic. October 2008 14