The 537 SYSTEM
OHSEP / SkyWarn / ARES / RACES
in Lafayette Louisiana
537 System Repeater Available for
Regular Amateur Use
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. Jeff Mahler - W5JSM
The need for the 537 System was apparent during Hurricane Andrew as Lafayette
Louisiana was being impacted. The ARES/RACES groups did not have solid communications
between the Office of Homeland Security and Emergency Preparedness (OHSEP) 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 edge of 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 also
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.
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 running about 100 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
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
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
small vertically polarized yagi beam.
A simple controller to identify the link transmitter
440 MHz antenna -
A 3 or 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!
Here is a simple picture of the configuration of the pieces.
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.
How Do I Use the 537 System?
The 537 System is full featured and easy to use.
Here are the basic rules:
- 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.
- 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.
- 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.
- The execution of the command code will not begin until you unkey your transmitter.
- 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 '*'.
- 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.
The 537 System uses a 4th generation implementation of the orginal
537 code (for a 6K controller).
The orginal code was enhance for 7K operation and tested on the
Opelousas Area Amateur Radio Club (OAARC) 147.150 and N5MEG 443.9 repeaters.
LRA thanks all OAARC members and N5MEG for serving as a test site during all
of the software development.
This also means that 90% of the commands are identical between the three repeaters.
You can obtain the
command function summary.
REMOTE RECEIVER LOCATIONS
||Lafayette, Congress and Cajundome
||Broussard, US 90 at the Southeast Parish Line
||Johnston St. Southwest of the Mall, at Fire Station #13
||Duson, I-10 near the Western Parish Line
||Carencro, I-49 near Exit 8
NOTE: The 537 System always transmits with a 103.5 PL tone. Your receiver
PL should always be set to 103.5 or turned off
The areas indicated in the drawing above are designed to show the concept
of the remote receivers used in the 537 System. Receiver coverage extends
beyond the rings for each receiver.
The drawing shows the overlap of receiver
coverage and indicates the best expected performance areas for handheld use of the repeater.
Users may use any receiver that works for their radio configuration. Users
may also coordinate and operate their own receivers. Again, the rings are
conceptual and do not represent a scientific placement based on measurement
or engineering calculations.
To look up a ham by name or callsign please click here.....
To lookup up possible areas of traffic congestion in Lafayette Parish please click here..... 911 Traffic
This website designed and maintained by Steve Mahler, KF5VH. Last partial update
07/27/2013. To mail a letter to KF5VH please click here.....