Printer Friendly

Designing an Effective RFP for Microwave Bypass System.

Change happens so rapidly in telecommunications that it seems as though we have had some acronyms and buzz words around for years. In reality, some of these words become old in a relatively short time. One of these is "bypass."

Business users can bypass the local telephone company in a number of ways: fiber-optic cable, microwave, satellite, other common carriers, coax, twisted pair, laser, infrared, customer-owned-and-maintained systems and so on.

This article addressed one of these "bypass" options--microwave. Most telecommunications consultants and managers do not have a good method for requesting a proposal from a microwave vendro to be certain of getting the best product for the least amount of money. This article addresses that problem and provides a sample request for proposal (RFP) for microwave.

It should be noted that this sample RFP is for the very popular 18-GHz microwave equipment, although the RFP lends itself to other frequencies simply by changing a few pertinent paragraphs.

We would like to acknowledge the assistance of Avantek's Fred Engle in developing this RFP. [Author's explanations for some portions are enclosed in brackets and italicized.] 1.0 General Terms and Conditions

1.1 General--[IDentify the specification of each microwave site, type and number of voice and/or data to be transported, extent of equipment protection/redundancy.]

1.2 Qualifications of Bidder

1.2.1 Manufacturing Experience--The manufacturer of the equipment sh all have produced microwave radio equipment for not less than four years. [However, this does not exclude the manufacturer from bidding a new product.]

1.2.2 Service--The bidder shall certify that spare parts will be maintained for a period of not less than seven years after the final installation of the system.

1.3 Explanation and Interpretation--Should the bidder observe any ambiguity, discrepancy, omission or be in doubt as to the intention and meaning thereof, he should immediately report such to the purchaser by phone adn in writing.

1.3.1 The purchaser will not be responsible in any manner for verbal answers regarding intent or meaning of the contract documents or for any verbal instructions, by whomsoever made, prior to the award of the bid. Bidders for their own protection should request, where deemed necessary, answers or instructions concerning all matters affecting their bids, in writing.

1.3.2 Should any conflict occur in the specifications, the bidder shall be required to contact the purchaser for clarification before submission of the bid.

1.4 Substitution of Equipment--In any section of the specifications where one or more manufacturers' brand name of equipment is specified, it indicates the type, quality, style, appearance and/or performance of the equipment to be furnished. The bidder may base the bid on one of the specified brand names, or may substitue a product equal to the sole judge of the equality of the products substituted for those specified.

1.5 Delivery Schedule--The bidder must supply quickest-possible delivery and state delivery date in the bid. [If desired, purchaser may specify specific delivery dates.]

1.6 Bid Proposal Contents--Bidders shall respond paragraph by paragraph to all the following specifications and shall clearly indicate compliance or list exception to these specifications. The bidder shall include with the bid a complete mateiral list of all equipment proposed (including pricing on each line item) and descriptive literature on each piece of equipment. Included in this proposal shall be rack-up drawings and block diagrams of the equipment supplied. [These details permit purchaser to fully evaluate cost/feature tradeoffs.]

1.7 Exceptions to the Specifications--In the event that the standard equipment proposed does not meet the requirements of these specifications, or does not include the operational features required, the bidder may take exception to the specifications if this is duly noted in the bid and an alternate bid is submitted.

1.8 Instruction Books--The successful bidder must supply one complete set of schematic diagrams and current instruction books with fully keyed descriptive parts lists for each terminal plus one additional set. [Purchaser should determine if two sets of books are adequate.]

1.9 Warranty--All workmanship, materials and equipment shall be warranted by the supplier for one year. Any materials or equipment that fails to provide satisfactory operation during this warranty period shall be replaced at the supplier's expense. Repair of the defective material or equipment shall be permitted provided that the repaired item meets original specifications. [Purchaser would be well advised to request that bidders quote costing for extended warranty periods of two, three, four and five years.] 2.0 Technical Specifications

2.1 Type-Acceptance Number--The bidder shall furnish the US FCC type-acceptance number for the radio equipment. [All bidders must obtain a type-acceptance number before equipment can be offered for sale in this country... Keep in mind that an FCC type-acceptance number does not mean that the FCC endorse the product or guarantees its reliability.]

2.2 Radio-Frequency Band--The microwave radio equipment shall be designed to operate within the frequency band of 18.36 to 19.04 GHz. Emission designation for this equipment shall be 20,000 F9Y. [Purchaser will be required to obtaiin a specific frequency assignment for each transmitter. In addition, frequency search and interference studies must be performed by a qualified firm.]

2.3 Design--The equipment shall be designed for continuous-duty service in a fixed plant environment; be of the latest design consistent with the present state of the art; be of all solid-stte design; and be engineered for a service life of not less than 10 years.

2.4 Operating Environment--The equipment shall meet all performance objectives over a temperature range of -30 to +50 degrees Celsius at a relative humidity of up to 95 percent (non-condensing) and up to an altitude of 15,000 feet above mean sea level.

2.5 Power Requirements--The radio equipment shall operate from the following primary power sources: -20 to -60 VDC or 90 to 240 VAC, 60 Hz. The bidder shall provide all other power supplies, inverters, regulators and so forth required to operate the system from the selected primary power source. Power fuse panels shall be provided with each equipment enclosure/rack. Power consumed by a transmit and receive pair shall not exceed 100 watts. [Purchaser must specify the primary power requirements of the project, plus define and special backup or standby power requirements.]

2.6 Connections

2.6.1 The electrical power connections shall be screw-type barrier strips. Terminal blocks shall be provided for interconnecting auxiliary equipment such as order wire, alarms and multiplexing. All cabling not designated coax or waveguide that's exposed to lightning shall be protected by gas-tube devices.

2.6.2 All active modules shall be replaceable without desoldering or resoldering.

2.6.3 Intra-racl cabling shall be accessible for testing and/or reconfiguration. In the event rear access is not readily available, the bidder must provide access to the signals via a front panel.

2.6.4 The bidder shall provide all cabling necessary to interconnect the radio and multiplexing system, alarm circuits, primary power, timing pulses and so on. The purchaser will be responsible for laying said cabling. [Purchaser should make certain that all new construction has cabling runs provided by the building contractor or, in the case of existing structures, determine the best method.]

2.7 Path Reliability--The system sh all be designed with as high a path reliability as reasonably obtainable. In no case shall the expected path reliability be less than 99.999 percent or have an outage time in excess of 5.15 minutes per year (based on a 24-hour day). The bidder must enclose expected path-performance characteristics within the submittal. These calculations are to be based on Barnett and Vigants, Formula 12, on page 60, in GTE Lenkurt's Engineering Considerations for Microwave Communications Systems--assuming average terrain and climate. [Purchaser should weigh the impact that an outage will have on the operation and increase the path-reliability requirements, if necessary.]

2.8 System Gain--The minimum system gain figures stipulated herein for this specification shall be defined as the level measured at the radio's antenna port connections and shall include all branching and filter losses. The receiver threshold shall be defined as a bit error rate of 10.sup.-6. [The system gain is a composite number that combines transmitter power output, receiver threshold and cabling/circulating losses.]

2.8.1 Unprotected System Gain--The unprotected system gain shall be 93.5 dB for bit rates up to 10 Mb/s and shall be 90.5 dB for bit rates up to 20 Mb/s.

2.8.2 Protected System Gain--The protected system gain shall be 89.7 dB for bit rates up to 10 Mb/s and shall be 86.7 dB for bit rates up to 20 mb/s.

2.9 Maximum Signal Gain--The radio system shall meet all performance objectives up to a maximum signal level of -20 dBm. [Signal levels higher than the specified maximum significantly degrade system performance by saturating the receiver's front end.]

2.10 Data Interfaces--In addition to transporting the proposed multiplexing data, the radio shall readily accommodate expansion to cover the following data interfaces: DSX-1, DSX-1C, DSX-2, ARC, Ethernet, interswitch linkc, local area, 9.788 Mb/s (6 T-1) and 19.062 Mb/s (12 T-1). The bidder shall detail the extent of reconfiguration required to accommodate the above data rates/interfaces. [To avoid problems at a later date, it is important that the expansion feature of the system be clearly defined at time of order.]

2.11 Reframing Requirements--The system shall be regenerative in design and provide reconstructed data, clock and digital service channel drops at each terminal and repeater location. [This feature significantlyreduces the cost of drop/insertion of service and alarm channels at repeater terminals. It also minimizes the noise associated with repeaters.]

2.11.1 Digital Service Channel--The system shall provide a digital service channel for the transportation of 0.3 to 3.4-kHz voice at a voltage level of +1 to 3 dB with a 600-ohm balanced interface. Alternatively, the system shall accommodate analog alarm and signaling equipment with a -10 dBm0 input level.

2.11.2 Data Service Channel--The radio system shall transport digital service data up to a maximum of 1200 b/s with an RS-232-C interface.

2.12 Maintenance Module--A maintenance module shall be supplied with each system to assist with monitoring and servicing the radio equipment. The module shall provide a visual indication of the received signal bit error rate and a digital readout of the following minimum signals on all radio equipment supplied: power supply voltages, transmitter RF power, transmitter AFC voltage, receiver signal strength, Receiver AFC voltage. [This feature simplifies servicing and maintenance of the radio equipment.]

2.13 System Maintenance--The radio shall be designed to facilitate maintenance in the field. Built-in test circuitry and fault indicators shall be incorporated in all plug-in modules (transmitter, receiver and power supply) and on all printed-circuit boards in the radio card cage. The built-in test circuits shall monitor critical internal signals and illuminate red fault indicators on the appropriate module or PC board when a fault condition occurs. The bidder shall provide the extender modules, cards or cabling as required to obtain access to the system component parts. [This feature eliminates a considerable amount of expensive test euipment.]

2.14 Alarm System--An alarm system shall be provided for remote monitoring of radio faults over the microwave link. The relay contact fault signals out of the radio shall be routed to the input of an alarm unit that shall convert the faults to auditory tones for transportation on the radio service channel. These fault signals shall be displayed at the master alarm station located in the main telephone operations center, enabling the staff at that location to determine the radio system alarm status. An audible alarm shall sound whenever the system goes into a fault condition. Guarding circuits and indicators shall be provided. [This enhances speed and accuracy of fault location.]

2.15 Order Wire System--An order-wire system with handset and speaker shall be provided for use with the radio system for direct voice communication between radio sites. Additional handsets shall be provided for order-wire extension in situations where the radio equipment is separated from the telephone equipment room. [Nice, but not really necessary in a one-hop microwave system. Note: order wire is not always operational during certain fault conditions; therefore, an independent telephone circuit between sites is really the best alternative.]

2.16 Protection

2.16.1 The system shall be equipped with automatic/monitored hot-standby protection. Two each power supplies, transmitters and receiver modules and two redundant sets of receive and transmit baseband signal-processing PC boars shall be provided for each. The protection module shall monitor all fault status signals from radio built-in test circuitry and provide the required switching commands to the radio needed to select the appropriate transmitter or receiver or baseband PC boards when a fault condition occurs. [This feature doubles the basic equipment cost. The purchaser should carefully weigh the merits of protection.]

2.16.2 In order to facilitate restoration time and simplify sparing at the RF level, both the transmitter and receiver RF units shall be modular in design and retunable in the field over the operating 2.2. The transmitter shall be provided with programmable frequency synthesizers capable of generating the designated RF frequency with an accuracy and stability of [plus-or-minus]0.003 percent. Microwave test equipment shall not be required to retune the transmitter or receiver. [This feature greatly enhances sparing and replacement time; the RF heads can be stocked in finished-goods inventory.]

3.0 Equipment Mounting

3.1 Indoor Equipment--All indoor radio equipment shall be mounted in fully enclosed equipment cabinets. The equipment cabinets shall be provided with removable hinged front and rear doors, AC power distribution strips and a grounding system. The front door shall be transparent to enable the service staff to observe the equipment status-indicator lights. [Most equipment locations are very hot and dirty. Enclosing all electronics in cabinets protects the equipment, and enhances the appearance and the reliability.]

3.2 Outdoor Equipment--All outdoor equipment shall be installed in weather-resistant enclosures. These enclosures shall be painted white. Enclosures containing active electronics shall be protected from direct sun radiation with sun screens. All cabling, with the exception of coax and waveguide, shall be protected from lightning with gas tubes. The equipment situated in the enclosures must meet operational temperatures, humidity and altitude constraints denoted in paragraph 2.4. The bidder shall provide fans and cooling systems as required to meet those constraints. 4.0 Waveguide System

4.1 Cabling--The bidder shall provide all required waveguide to connect the radio system to the antennas. The waveguide runs shall be held to a minimum to conserve fade margins. The bidder shall specify the waveguide type and length for all runs.

4.2 Mounting Kits--Hanger kits, grounding kits, bending kits and so forth required to hang the proposed waveguide shall be supplied by the bidder. [Purchaser should define type and height of all existing towers.]

4.3 Waveguide Connectors--Pressurized waveguide connectors shall be provided for each end of the waveguide. Any special tuning shall be the responsibility of the bidder. [Certain types of waveguide require tuning and/or cross-polarization correction.]

4.4 Pressurization--The complete waveguide run shall be pressurized, including antenna feed horn. An automatic dehydrator with rechargeable desiccant shall be provided for this purpose. [Short waveguide runs and most feed horns require a continuous pressurization.] 5.0 Antenna Systems

5.1 Antenna Types--High-performance (or optionally standard) parabolic antennas shall be provided. Antennas shall be sized in accordance with paragraph 2.7. [Interference from other microwave in the area may dictate the type of antennas required for the project.]

5.2 Type Acceptance--Antennas furnished for this system shall meet US FCC Category "B" as a minimum.

5.3 Radomes--Radomes are not required for this project. [Radomes are rarely used at high microwave frequencies due to their high-attenuation properties. However, interference problems could force their use.]

5.4 Mounting Systems--The bidder shall provide the antenna mounting system for attaching the antennas to their respective structures. The antenna mounting system shall provide fine adjustments for azimuth and elevation of at least plus or minus five degrees. [Antennas generally are mounted on a 4.5-inch outer diameter pipe that is welded or firmly attached to the support structure.] 6.0 Multiplexing System

6.1 General--The multiplexing system's function is to combine DS-1 lines into a single bit stream for transportation on a digital microwave radio system. The multiplexing system shall be configured to provide full-duplex service. [Purchaser should specify the number of T-1 lines to be transported. Be sure to include any active hot-standby spare T-1 channels.]

6.2 Input/Output Requirements--The multiplexing system's input/output codes and interfaces shall be compatible with the microwave radio system as defined in paragraph 2.0.

6.3 Equipment Mounting--All indoor multiplexing equipment shall be mounted in fully enclosed equipment cabinets. These cabinets shall be painted in a manner conducive to their location; that is, equipment located in the telephone equipment room shall match the switching equipment color scheme. The equipment cabinets shall be provided witgh removable hinged front and rear doors, AC power distribution strips and a grounding system. The front door shall be transparent to enable the service staff to observe the equipment status-indicator lights. [This section is entirely optional, depending upon the unique characteristics of the installation.]

6.4 Expansion Features--The multiplexer shall be fully wired at the factory for expansion to accommodate from one to 12 DS-1 channels. This expansion shall be obtainable by simply plugging in DS-1 channel cards into the existing common equipment shelves. The system's power supplies, common cards and associated subassemblies shall have sufficient reserve capacity to accommodate this expansion. [It is important to provide T-1 expansion to accommodate future telecommunications needs. This may not be required, however.]

6.5 Changing Data Rates--Changes in data rates shall be easily programmable to a maximum rate of 19.062 Mb/s (12 DS-1 channels). [Include whatever is appropriate for your situation.]

6.6 Protection

6.6.1 All multiplexing cards and power supplies common to the DS-1 cards and supportive of their functions shall be protected and redundant.

6.6.2 Protection at the DS-1 level shall be designated to allow a failed DS-1 channel card to be removed and replaced without affecting the operation of any other DS-1 channel.

6.7 DS-1 Interfaces--The DS-1 interface shall be Bell compatible.

6.8 DS-1 Test and Maintenance--Each DS-1 channel card shall have LED indicators on the front edge of the card. An LED shall be provided to display a DS-1 board fault. An LED shall be used to indicate a loopback condition and two LEDs shall be provided to indicate DS-1 channel transmit (input) and receive (output) data activity. The DS-1 channel cards shall also have input and output patch jacks on the front edge of the card that may be used for testing and maintenance of the DS-1 channels. The T-1 generator/monitor provided or an external commercial pattern generator/error-detector test can be plugged directly into these line patch jacks. The communications traffic DS-1 signals shall be interrupted when these patch jacks are used. [These fetures greatly simplify troubleshooting and reduce test equipment requirements.]

6.9 T-1 Generator/Monitor--A T-1 generator/monitor board shall be provided to plug indirectly into the multiplexer card cage. The T-1 generator/monitor board shall provide a T-1 (1.544 Mb/s) test signal output that can be patched into the test jacks on the front edge of any DS-1 channel card for test purposes. The T-1 generator/monitor shall monitor the received T-1 signal, com pare it with the generated test signal and provide a decimal display of bit errors detected on the channel. The T-1 generator/monitor shall also be capable of introducing errors in the test signal. The DS-1 channel producing the errors shall be immediately obvious and shall indicate an error count on the T-1 generator/monitor decimal error display. Only one generator/monitor shall be required, providing it can be moved between multiplexing systems. [This type of equipment is very difficult to troubleshoot without one.]

6.10 Built-in Test Equipment--Fault isolation and maintenance of the multiplexer shall incorporate built-in test circuitry to detect a fault condition and illuminate a red fault indicator on the appropriate module or PC board. When a failure occurs, the fault module or PC board shall be easily identified by observing the fault indicators. The module or PC board displaying the fault indication may then simply be unplugged and replaced with an operational spare. [This feature makes a troubleshooting much easier and faster.]

6.11 Multiplexer Controller--A controller module shall provide the capability to monitor the alarm status information and operating configuration of the local multiplexer unit as well as any remote multiplexer in the communications network. The controller/monitor shall continuously display the "summed" alarm status of the complete communications network. The controller module shall provide the capability to issue DS-1 channel loopback or common equipment channel A (CH A) or B (CH B) select commands or alarm status interrogations to any multiplexer in the communications network. The controller module shall contain the protection circuitry that continuously monitors the alarm signals for the local multiplexer unit. The controller module shall use the alarm signals to develop the required switching commands needed to automatically select the A or B common equipment channel should a fault cndition occur in the on-line common section. The protection scheme shall inhibit automatic switching into failed equipment. A switch shall be provided on the controller module front panel to allow manual selection of the automatic protection circuitry. [This feature enables the telecommunications staff to control and monitor remote radio and multiplexing equipment centrally.]

6.12 Power Requirements--The multiplexing equipment shall operate from the following primary power sources: -20 to -60 VDC or 90 to 240 VAC, 60 Hz. The bidder shall provide all other power supplies, inverters, regulators and so forth required to operate the system from the selected primary power source. Power fuse panels shall be provided with each equipment enclosure/rack. [Purchaser msut specify the primary power requirements of the project plus define any special backup or standby power requirements.] 7.0 Enginer, Furnish and Install

The bidder shall provide all labor and material necessary for the installation of the equipment specified in this document, including the installation of accessories, antennas, mounting systems and multiplexing equipment. On-site engineering, installation lineup and system acceptance is required. 8.0 Descrption of Premises

[Purshaser should provide a detailed description of the exact geodetic location of the microwave antennas, all existing towers, location of telephone equipment rooms, cable run availability, building accessibility and path distances.] 9.0 Work and Responsibilities

The bidder shall furnish a complete and detailed statement of work and responsibilities to be performed by both purchaser and bidder. [This prevents a lot of misunderstanding regarding responsibilities.] 10.0 Proposal Assumptions

All proposal assumptions shall be clearly identified in the bid package. 11.0 Training

The bidder shall outline the extent of training his or her firm proposes to provide. Costing shall be broken down to reflect the cost of elements for on-site training, in-factory training, number of personnel attending, Text material, air fare and subsistence allowance.
COPYRIGHT 1984 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1984 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Minor, B.; Pond, D.
Publication:Communications News
Date:Aug 1, 1984
Words:3881
Previous Article:How to Avoid and-or Suppress the Terrestrial Interference to TVRO.
Next Article:Dynamic Programming Approach for Single-Node Optimization.
Topics:


Related Articles
Broadband Cable-Satellite Connection Key Link for Business Communications.
The Case for Coaxial in Broadband Transmission.
Large Users Feel That Bypass Issues Don't Reflect Reality.
Microwave Role Grows in Hot Intercity Market.
Private Microwave Operators Get Opportunity to Make a Profit on Excess System Capacity.
Forecasts for 1986: A Banner Year for Changes in Telecommunications.
Misconceptions of wireless technology. (Network Features).
Staten Island borough president issues RFP for Sept. 11 memorial.
Microwave devices, circuits and subsystems for communications engineering.
Airport security.

Terms of use | Copyright © 2016 Farlex, Inc. | Feedback | For webmasters