The 537 SYSTEM
OHS&EP / SkyWarn / ARES / RACES
in Lafayette Louisiana

The Emergency Preparedness Repeater System in Lafayette Louisiana is the 145.370 repeater system (an Amateur (HAM) Radio System). The 537 Repeater System is sponsored and managed by the Lafayette Repeater Association (LRA). The system is owned by the Lafayette City-Parish Office of Homeland Security and Emergency Preparedness. The repeater trustee is Steve Mahler (KF5VH). Operational policy of the 537 System is set by the LRA board.

Members of the LRA board are currently: Mr. Steve Mahler - KF5VH / Mr. David Moore - KC5UKQ / Mr. Mike Gervais - KC5ZMF / Mr. George Jackson - KD5IHD

The need for the 537 System was apparent during Hurricane Andrew as Lafayette Louisiana was being rained on and blown about. The ARES/RACES groups did not have solid communications between the Office of Homeland Security and Emergency Preparedness (OHS&EP) Emergency Operations Center (EOC), the various shelters and the incident sites.

In 1994 a couple of local hams (Tom N5WDG and Steve KF5VH) finished a design for a distributed repeater system that would improve communications to local shelters and provide a lot of amateurs the chance to work on the construction of a repeater system. That design allows for multiple receivers to be placed as required to provide the desired coverage and a large central transmitter that radiates enough power to allow use of handheld (HT) radios in the shelters.

The 537 System is not designed to be a wide area system. The transmitting antenna is fairly low (only 100 feet), the radiated power is fairly high (for this part of the country), providing a solid signal inside many structures. But, by design, the low antenna limits the range of the system to Lafayette Parish and the surrounding parishes.

The 537 System is also designed to make use various advanced techniques to allow alerting of its user population. Most of the alerting techniques are for SkyWarn operations but may be used for any reasonable purpose. The System supports these operations:

• Tone and Voice Paging - in 2 tone and 5/6 tone format. Rebuilt and new pagers may be obtained.
• Numeric Paging - The repeater will call your pager and have it display 145370 plus an optional 4 digit message on request.
• DTMF Paging or Squelch - If you have a pager or radio squelch circuit that uses DTMF tones for control, the 537 System can alert you on 145.370 MHz.

The System can alert you, using one of several methods, to bad weather (or anything you want) if you have a pager or newer radio with DTMF squelch.

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Let's start with an overview of 537 System construction. The repeater is fairly unique in a couple of areas.

• The repeater can not operate as a single site (well, the 2M repeater can not ... the main site does operate by itself as a cross-band repeater). The minimum configuration is two operational sites. One of the two sites that must be in operation is the master transmitter site.
• The master transmitter site is located at the Lafayette Parish Courthouse in downtown Lafayette Louisiana. The master transmitter site consists of:
  • A 440 MHz antenna that is about 100 feet high. The antenna is tied to the receiver with a short length of 1/2 inch hardline.
  • The master transmitter is controlled with an S-COM 7K repeater controller with audio delay, autopatch and speech modules. The user is kept informed of repeater status by the 'announcer system' a unique software arrangement that provides for meeting, alarm and weather notifications. The controller also has autopatch capability that is also used for remote programming of the 7K controller from a personal computer. The controller can perform two tone pages, 5/6 tone pages, and DTMF pages.
  • The transmitter is an 110 watt unit that is loafing along at 95 watts. The transmitter feeds an antenna at 100 feet on a short length of 9913 coax.
  • Note that no 2 meter receiver is at this site and therefore no duplexor is required.
• The central receiver site is just one of any number of potential receiver sites. The 537 System Receiver #1 is located in just West of downtown Lafayette, Louisiana. The Receiver #2 site is in Broussard, Louisiana. The Receiver #3 site is in Duson, Louisiana. The Receiver #4 site is in Carencro, Louisiana. The Receiver #5 site is located Southwest of the Acadiana Mall in Lafayette. (See map at bottom of this page.)

  A generic receiver site consists of the following elements:

  • A two meter antenna with feed line to the receiver
  • A two meter receiver. Each two meter receiver in the system has a unique frequency / PL pair assigned for use. There are no voters in the system. The users selects the remote receiver of choice by a frequency / PL combination.
  • A 440 MHz transmitter with PL encoder. Note that all remote receivers transmit to the master transmitter on the same frequency and PL. Again, no duplexor is required at the remote receiver. The 440 transmitter is connected with feed line to the
  • A simple controller to identify the link transmitter
  • 440 MHz antenna - A 6 element beam is used over a very short distance. This allows the link transmitter power to be set very low
  • Low transmitter power allows the UPS system to have maximum duration.
• This configuration allows remote receivers to be 'on your way home' or anywhere else you need one. If you have a dual band radio in your car, we will coordinate a remote frequency and PL for you to use. Every time you leave the house you can take your remote receiver with you!

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Here is a simple picture of the configuration of the pieces.

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The 537 System alerting and speed dial slots are available to all 537 system members. The easiest way to become a member is to join Lafayette SkyWarn. Access to the system is without charge for SkyWarn members. If you just don't enjoy weather watching, contact the repeater trustee.

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How Do I Use the 537 System?

The 537 System is full featured and easy to use. Here are the basic rules:

1. The easiest way to start is using the central receiver. Set your 2 meter transceiver for 145.370 with a negative 600 KHz offset. You must set your radio to transmit a 103.5 PL tone. Set your radio to decode 103.5 PL if that option is available.
2. There are a lot more time delays in the transmit chain of this system than a little repeater. Please make sure you press your PTT and pause just a 1/2 second before beginning to speak.
3. Repeater features are activated by keying the repeater and sending touch-tone (DTMF) signals. Enter a 1 through 3 character command code to request a function.
4. The execution of the command code will not begin until you unkey your transmitter.
5. You may request multiple commands occurring sequence. To do this, enter the first command code, then enter the '*' key, then the next command code, etc. You do not need the '*' on the last command code. But, when you do this each command begins in sequence when you enter the '*'.
6. Before the 7K controller was added (Summer 1999) you needed to copy morse code or remember tone patterns to know about the state of the repeater. Now the 537 talks and the courtesy tone alerts you to three things. The 'waterdrop' courtesy tone is used in open and normal operation. The waterdrop changes to a triple beep to identify an alarm or weather condition. A double beep means the audio is arriving from the linking system.
7. The 537 System has an integrated WRSAME radio that monitors the National Weather Service NOAA VHF broadcast on 162.550 MHz. When this radio detects EAS coded weather watches and warning from the NWS, the repeater automatically changes its alert mode and begins a paging cycle. Users may also enter a command code to monitor the WRSAME radio audio at any time. You can read more details about the WRSAME use if you want to control the system.

REMOTE RECEIVER LOCATIONS

Receiver Name	Frequency	PL Tone	Location
CENTRAL	145.37 minus	103.5	Lafayette, Congress and Cajundome
SOUTHEAST	145.37 minus	94.8	Broussard, US 90 at the Southeast Parish Line
SOUTHWEST	145.37 minus	141.3	Johnston St. Southwest of the Mall, at Fire Station #13
WEST	145.37 minus	114.8	Duson, I-10 near the Western Parish Line
NORTH	145.37 minus	127.3	Carencro, I-49 near Exit 8

This website designed and maintained by Steve Mahler, KF5VH. Last updated 7/1/2003. To mail a letter to KF5VH please click here.....

mahler@louisiana.edu