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TELESCOPE OPERATIONS

GREEN BANK RADIO COMMUNICATIONS - An Operation’s Description

Table of Contents

2. System Description

    2.1. Base Sets
    2.2. Repeater
    2.3. Mobile Units
    2.4. Portable Units      

    3.1. Channels and Their Use
    3.2. System Range 
    3.3. Power Requirements and Battery Life

    4.1. General Responsibilities
    4.2. Basic Concept of Radio Use
    4.3. Safety
    4.4. Procedures

6. Technical References

7. Acknowledgments

1. Introduction. The purpose of the Green Bank radio communications system is to provide an efficient and easy to use means of passing official or operational information between operations, maintenance, and management personnel. Given the nature of our business and need for communications in areas where phones or intercom systems are impractical or unavailable, the adoption of a radio communications system was a natural choice. The radio system we use consists of various components maintained, operated, and controlled by different divisions. As with most systems, rules and procedures have been established to ensure compliance with safety and proper use of the radios. Specific rules governing the use of this system are outlined as NRAO Green Bank policy and within Federal Communications Commission (FCC) regulations. Please review these documents as well.

2. System Description. The main components of the radio communication system are described below. In the paragraphs that follow, bracketed numbers reference related source documentation. Please see the paragraph on technical references for further details.[Ref. 6.1,6.2]

2.1. Base Sets. Base sets are non-portable radio units positioned at specific locations. At Green Bank, these locations include the GBT Operations Center (“GBT Ops”), Interferometer/20 Meter/OVLBI control room (“Interferometer Ops”), and the receptionists office (“Switchboard Base”). These units, and personnel operating them, will act as mini communications centers tasked with monitoring and managing radio communications on-site and within their respective areas of concern.

2.2. Repeater. This component can be thought of as a combination antenna and electronics unit that boosts the power level of radio signals received and transmitted, thereby increasing the range of smaller mobile and portable units. A repeater is also necessary as a means of bringing radio signals into a base set located within a shielded environment, like the GBT control room.

2.3. Mobile Units. These are radios installed in vehicles, much like a CB radio, and are operated primarily by maintenance technicians, mechanics, or persons in key management positions. Motorola MaxTrac Low Band VHF mobile radios are the type currently used at Green Bank.

2.4. Portable Units. These are hand held units (walkie-talkies) that provide communications in areas where other communication devices are unavailable or impractical. Motorola MT1000 portable radios are the type currently used at Green Bank.

3. System Specifications. The following information details system characteristics and capabilities.[Ref. 6.1,6.2]

3.1. Channels and Their Use. The table below shows channels available and their planned use.

Channel # Expected Use 1 Administrative and Works Area (repeater) 2 Operations Calling / Site Wide (direct) 3 Operations Calling / Site Wide (repeater) 4 Operations Calling / Site Wide (direct) 5 Assigned by Duty Operators (repeater) 6 Assigned by Duty Operators (direct) 7 Assigned by Duty Operators (repeater) 8 Assigned by Duty Operators (direct) 9 Assigned by Duty Operators (repeater) 10 Assigned by Duty Operators (direct) Note: Repeater indicates communications are via this device. Direct refers to direct or “radio-to-radio” communications.

3.2. System Range. The system provides site-wide communications coverage.

3.3. Power Requirements and Battery Life. Base sets and mobile radios use commercial power or automobile battery power respectively and therefore require little attention in normal use. Portable radios use rechargeable batteries. These radios should be placed in recharging stands when not in use. When fully charged, the portable radios should provide a full day of service under normal use.

4. Operational Use of the Radio System.

4.1. General responsibilities.[Ref. 6.1]

4.1.1. Telescope Operators at their respective telescopes shall:

4.1.1.1. Issue portable radios and provide a briefing on there use as needed.

4.1.1.2. Coordinate channels used.

4.1.1.3. Act as the focal point (base station) for telescope operations radio traffic.

4.1.2. Radio Users (mobile/portable units) shall:

4.1.2.1. Use radios appropriately and according to NRAO Green Bank/FCC policy and procedures.

4.1.2.2. Handle radios appropriately to minimize damage.

4.1.2.3. Return portable radios after use and/or when in need of repairs/service.

4.1.3. Radio Communication System Maintainer(s) shall:

4.1.3.1. Inspect, service, and repair (or coordinate repairs) all system hardware as needed.

4.1.3.2. Troubleshoot and correct system problems.

4.2. Basic Concept of Radio Use. In practice, here’s generally how the radio system will be used:

4.2.1. An individual preparing for work/access on a telescope comes to the duty telescope operator to check out a radio.

4.2.2. The duty operator issues a radio, assigns a channel, and provides a briefing on radio use (as needed).

4.2.3. The individual carries out their work (using the radio system as necessary). The duty operator monitors radio communications and responds as the situation dictates.

4.2.4. Upon completion of their work, the individual returns the radio to the duty operator where it's checked in. Any problems with the unit should be noted at that time.

4.3. Safety. The improper use or handling of this radio system can result in hazardous situations. These hazards include, but are not limited to those associated with improper charging of rechargeable batteries, electrical shock, or exposure to radio frequency electromagnetic energy. Care should be taken to review the safety information provided with each radio component that you intend to use.[Ref. 6.3.]

4.4. Procedures. Specific procedures concerning the operational use of the radio system are outlined in published procedures/checklist located in the GBT Operations Center. Please refer to them as necessary.

5. Points of Contact. Refer to the latest maintenance responsibility listings for individuals assigned to this system.

6. Technical References.

    6.1.   Knapp, E., Niday, C. [1999] Two-way Radio Policies and Procedures/FCC Rules and Regulations, Sep 99
    6.2.   Motorola [1992] MT1000 Portable Radios Operating Instructions, Motorola Radio Products Group, 1990  
    6.3.   Motorola [1998] Safe and Efficient Operation of Motorola Two-Way Radios, Motorola Radio Products Group, 1998

-- DavidRose - 01 Oct 2003