Difference between revisions of "RF Engineering"
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*[http://standards.ieee.org/colorbooks/sampler/greenbook.html IEEE Std 142™ Recommended Practice for Grounding of Industrial and Commercial Power Systems.] | *[http://standards.ieee.org/colorbooks/sampler/greenbook.html IEEE Std 142™ Recommended Practice for Grounding of Industrial and Commercial Power Systems.] | ||
+ | *[http://www.nfpa.org/catalog/product.asp?pid=78008 NFPA 780: Standard for the Installation of Lightning Protection Systems] | ||
*[http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70&EditionID=238 2008 National Electrical Code online - Requires Site Registration] | *[http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70&EditionID=238 2008 National Electrical Code online - Requires Site Registration] | ||
*[http://www.polyphaser.com/technical_notes.htm List of PolyPhaser tech notes on Grounding PDF format] | *[http://www.polyphaser.com/technical_notes.htm List of PolyPhaser tech notes on Grounding PDF format] |
Revision as of 09:29, 7 April 2010
Before getting started will want to study or refresh your knowledge of Kirchhoff's Law, Ohm's Law and Watts Law
Contents
Electricity Supply
Alternating Current (Mains)
Direct Current (Battery)
UPS & Battery Backup
How to calculate what size battery system is needed for emergency backup
1. Find the current drain in Amps during transmit, receive and stand-by operation for each piece of equpment you will be attaching to the battery backup system.
This usually can be found in owners manual specs page or on the internet.
2. Determine the equipment's Duty Cycle.
Duty Cycle is expressed as a series of three percentages:
Transmit | Receive | Stand-By | Device .00 | .80 | .20 for a Scanner (low) .50 | .50 | .90 For a Transceiver (Medium) 1.0 | .00 | .00 For a Transmitter TV broadcast (High)
3. Use the following formula to calculate the average current required per device.
- Where i is the DC current in Amperes required during transmit (TX), receive (RX), and stand-by (SB)
- Where %Duty is the duty cycle represented as .xx ie. .50 is 50%
Average Current in Amps = (I_TX)(%Duty)+(I_RX)(%Duty)+(I_SB)(%Duty)
4. To determine the battery size required, multiply the average current in Amps by the number of hours of backup power required.
Battery/UPS Size = (Average Current in Amps)x(Number of hours backup power required)
Grounding
- IEEE Std 142™ Recommended Practice for Grounding of Industrial and Commercial Power Systems.
- NFPA 780: Standard for the Installation of Lightning Protection Systems
- 2008 National Electrical Code online - Requires Site Registration
- List of PolyPhaser tech notes on Grounding PDF format
Manuals
General Electric
Lynchburg Book of Instructions (LBI) Term for GE Manuals
All LBI manuals are in Adobe PDF format and under 5Mb
- LBI-39148B Standards For Site Construction & Contract Install
- LBI-39179B Fiberglass & steel Comp & Lightweight Comm Shelter
- LBI-39184A Concrete Shelter Specifications - Bullet Resistant
- LBI-39185 Tower Requirements & General Spec - Installation
Motorola R56 Standards and Guidelines for Communications Sites
- Motorola Part Number 68-81089E50 Printed version
- Motorola Part Number 98-80384V83 CD-ROM version