Radio Procedures
First Responders for Severe Weather
Monitor 146.760 MHz. - The Radio Home of the Weather Net

Backup Frequencies

It is possible that an equipment failure might cause the prime weather net repeater on 146.760 MHz. to go off the air.  Before you move to an alternate frequency make sure that your radio is encoding or transmitting a PL tone of 123 Hz.  All receivers on 146.760 MHz. and our backup frequencies require a PL tone of 123 Hz. for access. 

If you are unable to access the weather net on 146.760 MHz. You should try these frequencies in the order listed. 

  • 146.970 MHz. - first backup frequency
  • 147.330 MHz. - second backup frequency

When you find an operational repeater, make a query on the air to be sure that you have found the correct repeater.

Pager Capability on your Radio?

If you have standard paging capability on your radio you can receive the paging we send to our Net Control Operators.  Motorola calls this Quick Call 2 paging or QC2 paging.  Here are the tones transmitted at the beginning of a net.

    600.9 tone 1 for 1 second

    979.9 tone 2 for 3 seconds

These tones are also used when the National Weather Service wants to talk to us.  Note that the words ‘Weather Alert” will be transmitted after the tones.

Radio Net Procedures
COSWN conducts two types of on-air nets, a readiness check net or a severe weather net.  Each net is designed to serve a specific purpose.  The readiness check has several goals whereas the severe weather net has a more focused purpose.  When either of these nets is in session the normal courtesy tone is replaced with the Morse code character "W".

Both nets are operated as directed nets.  A directed net means that the net control station, usually know as Columbus Weather,  manages all communications on the net.  The basic operating principle of a directed net is that you identify your station by transmitting your callsign and wait to be acknowledged by net control.  This applies whether you are responding to a call from net control or you have a message for net control. This brings order to the information flow and helps ensure that urgent communication can take place.

You can help net control prioritize your message by using key words when you transmit your callsign. For example, if you spot a funnel cloud, transmit your callsign followed by the keyword "emergency". Any message you have related to a life-threatening situation can be classified as an emergency message. If you have important information related to current radio traffic, you can simply transmit your callsign.

A directed net is easy to participate in if you listen carefully and follow the directions provided by the net control station.  Listening and understanding what you’ve heard makes your participation more valuable and increases the effectiveness of the net.

It can become very busy at net control.   We monitor several radios and satellite communications.  If we don’t respond within 5-7 seconds call again.

Readiness Check

The primary purpose of the Readiness Check Net is to provide an opportunity for field spotters to test their equipment and the transmission path to the repeater system.  This net is conducted each Tuesday evening at 7:30 PM during severe weather season, roughly April through the beginning of September.  During the out season months we conduct the readiness test on the third Tuesday of the month.

You might ask, "Why do I need to test my equipment?  I use it everyday and it works fine."  Your equipment may be working fine but sometimes we discover that the repeater system is not working as well as it should be.  By checking in regularly we get familiar with your signal quality and that of other stations and can tell when a repeater problem may be present.  The readiness net helps us check our equipment as much as it helps you. Let us know if our signal is less than ideal as well.

To gain the maximum benefit from the readiness net you should be at your spotting location, if possible, and operating on emergency power.  Commercial AC is often interrupted during severe weather.  Being at your spotting location will help you identify any special operating conditions that might prevent you from communicating with us at net control.

Remember that a storm with heavy precipitation cuts your signal strength significantly.  A strong signal in good weather has a good chance of being readable during a storm.  If net control reports that your signal is noisy or marginal, that is your cue to take some action or we won’t be able to hear you during severe weather.  You may find that a different antenna works better or that a small power amp is necessary.

We emphasize the use of standard International Telecommunications Union phonetics for your callsign during all nets and ask that you  initially respond with your full callsign.  For example, N8WX would  check in as "November Eight Whiskey X-ray."   In a noisy transmission P, C, V, B and T can sound similar.  When spoken phonetically PAPA, CHARLIE, VICTOR, BRAVO and TANGO are much   easier to understand.

Conduct of the Readiness Check Net

  1. The net begins with net control requesting announcements and priority traffic.
  2. Check-ins are taken county by county throughout central Ohio.  Franklin County is divided into four quadrants and check-ins are taken from each quadrant.
  3. Net control will ask for your full call sign. When net control acknowledges you, respond with your callsign, name and location.  FCC regulations require identification of your station.
  4. The location you provide should be the nearest major intersection or landmark.  Where it is possible for two streets to intersect with each other more than once, clearly identify which intersection (e.g., I-270 and SR 23, Worthington). This normally occurs where an interstate outer belt surrounds a city.
  5. After taking check-ins, announcements are made and a short training tip may be shared.
  6. A call for questions and comments will be made. This is an excellent time to ask questions you may have or make announcements about upcoming weather or amateur related programs or topics.
  7. The net finally ends with the current forecast for central Ohio.

Severe Weather Net

A severe weather net is started when severe weather threatens, is present in the area or the National Weather Service has issued a severe thunderstorm or tornado warning.  Either of these warnings is considered an emergency condition because of the threat to life and property.

Usually a warning from the NWS brings up a net but a net can also start when a weather spotter encounters severe weather conditions.   Instructions are provided later on how you can bring severe weather to the attention of net control stations and get the NWS involved.

A severe weather net is focused on gathering information from field spotters.  The NWS RADAR cannot see conditions at ground level.  In the central Ohio area, depending on distance from the RADAR and terrain, NWS Radar may not see below 4,200 to 7,000 feet or more in some parts of our area.  For this reason the NWS depends on reports from weather spotters.  Trained spotters can identify changing conditions through subtle visual clues that can go undetected on RADAR.

Of particular interest to the NWS are reports of severe weather and significant damage. Severe weather is defined as:

  • winds in excess of 50 MPH
  • rainfall rate greater than one inch per hour
  • hail size inch or larger
  • wall cloud showing signs of rotation
  • funnel cloud
  • tornado

Damage reports should generally be held until net control requests them unless:

  • damage occurred within the last 10 minutes
  • damage is substantial
  • damage clearly indicates an intense storm
  • damage has created a life threatening situation

If you have a damage report that fits these guidelines, call net control and use the keyword "damage." This information can help the NWS issue accurate warnings for areas in the path of the storm.

As mentioned earlier you can bring severe weather to the attention of weather net control operators by depressing touch-tone digit 5 for 5 to 7 seconds.  Upon receipt of DTMF digit 5, the repeater will transmit a signal that will activate voice pagers carried by weather net control operators.  One or more of the net control stations should answer you within a few minutes.

An important point to remember during a severe weather net is to keep transmissions short and to the point. This keeps the air clear for priority transmissions.

Conduct of the Severe Weather Net

  1. The net begins after the repeater is placed in weather mode.
  2. Net control will make an announcement about the current weather situation.
  3. Net control will ask for stations to report in if they are experiencing any severe weather conditions which are:
      • winds in excess of 50 MPH
      • rainfall rate greater than one inch per hour
      • hail size inch or larger
      • wall cloud showing signs of rotation
      • funnel cloud
      • tornado
  4. If no stations respond, net control will ask that any station in the affected area report conditions in their area.
  5. As further updates are received from the NWS they will be passed along to all listening stations.
  6. If a funnel cloud or touchdown is reported, the net will go into an emergency state and priority will be given to stations reporting and tracking the funnel cloud or tornado.  Other stations should hold their transmissions until cleared by net control.
  7. Depending on current weather conditions, net control may ask for damage reports.
  8. After all warnings have expired and net control has received no further reports of severe weather the net will end.  Net control will provide an update on current and expected weather conditions as the net is terminated.

Lightning Reports

You will note the absence of lightning as criteria for severe weather.  All thunderstorms contain lightning. Lightning is the thunder in thunderstorms.  All lightning is deadly no matter if it’s cloud to cloud, cloud to ground, ground to cloud, heavy, light or striking every two seconds.

During training sessions the National Weather Service does not instruct spotters to report lightning and will not accept reports of lightning during severe weather.  Please note that it is acceptable to report lightning damage, especially if you witness it or come across it.

CTCSS/PL Tips and Hints

There has been some concern and confusion about PL and how it is used when the Weather Net is in operation.  At all times the 146.76 repeater encodes a PL of 123 Hz. on its output.  For those decoding PL, much of the interference from intermod is muted.

The repeater also decodes a PL of 123 Hz.  All receive sites on this repeater require a PL of 123 Hz. for access
 

Glossary of Terms

  • Courtesy tone – an audible indication that a repeater user may go ahead and transmit (sometimes referred to as a "reset beep").
  • CTCSS – continuous-tone coded squelch system.  This is a system in which the repeater’s receiver will only respond to signals that carry a sub-audible tone in addition to the audible voice signal transmitted by a ham transceiver.  The purpose is to reduce the amount of unwanted signals that may activate the repeater. Also called PL.
  • Decode – to receive a sub-audible tone.
  • Directed net – a net with a Net Control Station (NCS) who directs the net’s activity.
  • DTMF – dual tone multi-frequency dialing signals sometimes called ®touchtone
  • Encode – to send a sub-audible tone along with your transmitted signal.
  • fill - repeat of  “missing” information
  • Mode – same as state.
  • Net – short for network; it’s a formal gathering of hams on a specific frequency at a specific time for a specific purpose.
  • Phonetics – standard words used on voice communication to make it easier to understand letters of the alphabet.  COSWN uses standard ITU phonetics.
  • PL – this is the Motorola Corp.’s registered trademark term for the CTCSS implementation it calls "Private Line".
  • Repeater – an automatic relay device that simultaneously receives and retransmits radio signals. Repeaters are used to extend VHF communication range.
  • State – the pre-programmed condition of a repeater system consisting of a defined set of characteristics to meet specific operational requirements.  For example, a state or mode could be created that would disable certain repeater features, such as the autopatch, overnight or during emergencies.
  • Touch Tone – Bell System trademark name for DTMF dialing signals

 

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