California Department of Transportation
 

Contract 06-0L7304

The responses to bidder's inquiries, unless incorporated into a formal addendem to the contract, are not a part of the contract and are provided for the bidder's convenience only. In some instances, the question and answer may represent a summary of the matters discussed rather than a word-for-word recitation. The availability or use of information provided in the responses to bidder's inquiries is not to be construed in any way as a waiver of the provisions of Section 2-1.03 of the Standard Specifications or any other provision of the contract, the plans, Standard Specifications or Special Provisions, nor to excuse the contractor from full compliance with those contract requirements. Bidders are cautioned that subsequent responses or contract addenda may affect or vary a response previously given.


Q1) The wireless interconnect specified does not use radios or antennas which can operate as local repeaters. Our examination of the signal paths indicate structures and topography which will prevent the wireless interconnect from operating. Was a field survey done by Caltrans to assure the wireless interconnect would work at the pole locations and antenna types+heights using unlicensed 5.8 GHz radios with less than 1 watt emitted power?

A1) A line-of-sight site survey was perform by Caltrans. The WIS will work at the pole locations and antenna types+heights shown on the plans and using unlicensed 5725 to 5850 MHz radios as specified in section 10-3.13 of the special provisions . 9Nov10.


Q2) The wireless interconnect can be made to work with radios operating in the 900 MHz band with different antennas than those shown on drawing E8, provided those radios also operate as local repeaters. Will Caltrans accept an operational solution using 900 MHz radios, since the 900 MHz band enables better signal propagation?

A2) NO. Per section 10-3.13 of the special provisions, frequency range is from 5725 to 5850 MHz. 9Nov10.


Q3) How does Caltrans propose to serve the 9 wireless sites East of location 7 when the radios specified only have 6 channels? Will the communication protocol only operate on a polled basis to ensure no conflicting use of a channel?

A3) Section 10-3.13 of the special provisions indicate a point to multipoint operation under the Radio Transceiver and Access Point specifications. The plans reflect the Access Point radios capable of supporting several Radio Transceivers (Subscriber Units). 9Nov10.


Q4) Enclosure construction was described using the word "doors" which is a plural. Drawing E8 does not show multiple doors on the enclosures. We will provide a single door on each enclosure. Does Caltrans agree that will comply with the Special Provisions?

A4) Sheet E-8 Notes 1 and 2 are correct, the cabinet with a single door is acceptable. The special provisions are amending section 86-3.04A cabinet construction. 9Nov10.


Q5) Drawing E8 shows a photovoltaic power supply with 4 panels and 4 batteries for a site with 2 MVDS units and a radio. We infer that a site with 1 MVDS unit and a radio will have 2 panels and 2 batteries. Why was a detail drawing for a site with 1 MVDS unit omitted, since that is the predominant configuration of solar powered sites?

A5) Per Sheet E-8, Detail A, photovoltaic locations shall have four solar panels and four batteries. Detail A indicates a second MVDS SENSOR (WHERE REQUIRED). 9Nov10.