Training Tips

The Central Ohio Traffic Net handles traffic 365 days per year. Each day we hold a regular session and we hold special sessions throughout the year for training sessions and for emergencies as events warrant. As a training net, we pay special attention to our procedure and help new traffic handlers.

When we hear mistakes (as they invariably will) and have questions, our more senior handlers offer their words of wisdom. Here we memorialize some of them.

Making the National Messaging Layer Work For All

posted Apr 29, 2020, 4:48 PM by C. Matthew Curtin   [ updated May 3, 2020, 6:14 AM ]

Amateur radio operators have equipment, skills, and privileges that make it possible to communicate across town, across the world, next door, and into space. We often hear the phrase "when all else fails," and sometimes even tell others that "ham radio saves lives."

What does that mean in practice? How can someone who is not an amateur radio operator communicate when there is a failure of communication infrastructure?

With the help of his son Thomas, the Central Ohio Traffic Net, and Chris KV8Z, Matthew KD8TTE was able to discuss this problem and demonstrate a solution to a Boy Scout troop yesterday evening. Presented via Google Meet, the scouts were able to see and hear Thomas talk with Matthew by FRS "walkie-talkie" radio, who was able to originate a radiogram, then the scouts saw Matthew relay the radiogram to a station that was out of the affected area but could be heard on Matthew's radio. Scouts then heard delivery of the message by phone to a concerned relative, played by a scoutmaster.

To lay some foundation and to provide visual aids to illustrate what was happening, the presenter used the following slide deck. We hope that this demonstration of the National SOS Network and the Neighborhood Hamwatch relates to the National Traffic System (NTS) and one means that NTS supports those who need to communicate "when all else fails."

Thank you to everyone who participated!

Use of X in radiograms

posted Dec 1, 2019, 4:50 PM by C. Matthew Curtin

Radiograms often need to include more than a single sentence worth of information. How do we separate one sentence from another, where we'd normally put a period at the end of the sentences?

A break in thought—a "STOP" in the parlance of old timey telegrams—is written with a single initial X. For example,


could be interpreted as

I love bacon. For breakfast, I had coffee.
I love bacon for breakfast. I had coffee.

To ensure that the break goes in the right place, we'll use initial X to indicate a break in thought.


Note that there isn't a trailing X in the radiogram. The end of the radiogram or an obvious change in thought (e.g., "73") does not require the X.

Remember that radiograms as formatted for transmission, not for delivery. Air time is very "expensive," and we work to make transmission as efficient as possible to avoid taking time to transmit. Radio operators are ostensibly trained and know how to make sense of how the radiograms are formatted, just as software is able to make sense of data encoded according to a given specification. When we get to the stage of delivery, we turn the text into standard language. The delivering station knows that the end of the message includes a period, and will add one when delivering; there's no need for one during transmission.

A Radiogram Occasion

posted May 6, 2019, 10:52 AM by C. Matthew Curtin   [ updated May 6, 2019, 11:04 AM ]

A colleague and I were planning a little hiking trip. The idea was to get out away from the city and infrastructure, spend a little time getting heads clear. I'd set up an HF radio station and get some air time while he got a look around for things that might make for good exploration on a future visit to the area.

His wife was close to delivering a child but with parents in town and prepared for the event he thought a little day trip only an hour or so away might be just what he needed. By the time the day arrived, so had the baby. No day trip was to be had but it did seem a good occasion for a congratulatory note. Naturally I thought the way to take care of that was with a radiogram.

As it turned out, the radiogram also made for a good example of how to deliver a radiogram, and how that's different from relay—especially when it comes to the use of numbered radiograms. The message was promptly relayed once on the net and delivered just a few minutes later. The next day I got a message back from my colleague, who wrote in part, "That radiogram has been the best congratulatory message I have ever received."

Messages can be both novelties that bring the recipient a little more joy and good training for the operators originating, relaying, and delivering them.

Use of "Time Filed" in the Preamble

posted Apr 17, 2019, 5:23 PM by C. Matthew Curtin

On this evening's net, Gene N8YRF raised an important issue on the use of the (optional) Time Filed element of the Preamble of the Radiogram. He commented that it is not generally used for Routine traffic but is used during Emergency and Priority precedence traffic.

Emergency and Priority traffic are to be handled with particular urgency, so the time of day in that case is generally quite sensible to include.

As with most amateur radio nets, COTN's call-up begins with identification of the net and a call for stations with Emergency or Priority traffic. In the event that we have someone list such traffic, we'll handle it immediately—even before the rest of the net call-up. (Note MPG 4.6.3, "Listing Formal Radiograms" says that Emergency traffic is to be declared and handled immediately by any means necessary.)

In the event that either Emergency or Priority traffic is brought to the net, Net Control will call for another station on frequency that can handle the traffic and wherever possible move the stations to another frequency to handle the traffic while the rest of the net call-up takes place. Once traffic has been handled, stations will return to the net frequency and advise net control that they're back and therefore ready for additional business.

In addition to the case of Emergency and Priority traffic, there is the matter of handling instructions B (HXB). HXB is followed by a number to indicate the number of hours that the message is to stay alive. For example, HXB 36 means that the message is to continue moving toward delivery but if delivery has not happened 36 hours after Time Filed, the message is to be canceled and serviced back to the station of origin.

Finally, it's important also to remember that when using Time Filed, you need to ensure that the time is correct. Standard amateur practice is to use universal time (UTC, also known as Zulu time) to ensure that the time is unambiguous through timezones. Hence, something filed at 1200 APR 17 would be 8:00 A.M. eastern daylight time, which is four hours behind UTC. If local time is to be used, amateur practice is to use L at the end of time filed, e.g., 0800L. A timezone designator is also allowable, e.g., 0800EDT. UTC is preferable.

For additional information, please see Chapter 1 of the MPG, specifically 1.1.7, "Time Filed, [TIME], Optional."

How Do We Route Traffic?

posted Feb 3, 2019, 7:25 AM by C. Matthew Curtin   [ updated Feb 3, 2019, 7:30 AM ]

Most VHF traffic nets are thought of as "local": the "first mile" or "last mile" of the system: involved in traffic relay only as needed to receive traffic to deliver, or to relay traffic originated. With a footprint of approximately 10 counties, VHF contact to EMA stations at the county and state level, as well as stations able to relay traffic to other radio services including MARS and SHARES, COTN has a good deal more relaying than many other "local" nets.

COTN net control stations and stations that can perform relay services therefore need to pay attention to traffic listed, and the capabilities of stations on frequency.

A good example of how this can work took place in the past week. We had routine precedence traffic listed for Hardin County, about 50 miles from our primary repeater's transmit site, about 30 miles from the nearest receive site for the repeater system. Normally traffic going that far would be outbound, headed to HF.

A station in Marion County, about 40 miles from our transmit site and 20 miles from the nearest receive site, volunteered to take the Hardin County traffic. He advised us that there as a weekly net in Marion County that evening that often had a Hardin County station check in. Though it is not an NTS or RRI affiliate, the net would handle the traffic under the care of the Marion County operator.

Thus, rather than waiting for the next cycle for HF and finding a station in or near Hardin County to take the traffic, the message got through and was delivered correctly by relaying through two nets in about 45 minutes. The attached image shows the relative positions of the sites in question.

We note that especially as we consider times where sunspot activity or other atmospheric conditions impede HF operations, the ability to employ relay to ensure timely delivery is an important part of providing a resilient and reliable message relay service.

Where can I direct practice radiograms?

posted Mar 25, 2018, 5:12 AM by C. Matthew Curtin

Learning how to originate radiograms can be exciting. Refining and maintaining the capability requires regular practice. Are you regularly sending radiograms? Where can you send them to keep the skill up?

There are several places you can go for good places to send radiograms. maintains several lists for people who are interested in receiving traffic. See the RadiogramCQ CQ Lists. Reach out to your local Section Traffic Manager, or Section Manager, to find out where there are people happy to take practice traffic. The ARRL has a list of sections and how to reach the leadership. Finally, there's COTN's own humble contribution to this effort; being a training net, we have plenty of our own operators with a need to direct traffic somewhere, and if we can help others in doing so, so much the better! If you'd like to join our list of practice traffic recipients, send a radiogram to our net manager with your name, city/state/zip, and phone number.

Central Ohio Traffic Net Practice Traffic Destinations. Send a radiogram to any of these at any time!

Third-Party Traffic Handling Is a Public Service

posted Apr 2, 2017, 4:24 PM by C. Matthew Curtin

Amateur radio is a great hobby, where one can tinker and experiment to learn the art of radio, to advance the state of the art, and even to enhance international goodwill. All of these benefits are memorialized in the opening of Title 47 of the Code of Federal Regulations Part 97, the rules that define the amateur radio service in the United States. The very first benefit of all, however, is something more serious:

(a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.

Here is traffic handling: a voluntary noncommercial communication service for the public. Since the earliest days of amateur radio, our technology and operating skill have been ready to serve. When one of the worst windstorms ever experienced by Ann Arbor, Michigan blew through on the night of March 21, 1913, toppling houses and telegraph lines. The situation worsened when by a week later, the city of Freemont, Ohio was under water and flooding was prevalent throughout central Ohio. During this time, amateur radio operators worked day and night to keep the communications flowing though other systems had failed. Lessons learned from this early event were clear. Amateurs should "Put [their] aerial up so it will stay up, no matter what happens, and learn to handle messages at commercial speeds, for [they] may be called on to handle emergency messages when [they] least expect it." Radio, "in the hands of the amateur, while it is used by some as a plaything, is capable of doing excellent service in time of need; and we hope the work done by these men who did all they could to maintain communication between the flood stricken cities and the rest of the world, will long be remembered." (Modern Electronics. "The Wireless Amateur in Times of Disaster." April 1913)

In those days, the response was ad hoc. Today, however, we are far better organized to handle events large and small. This is due in no large part to the voluntary public service rendered by radio amateurs. The Central Ohio Traffic Net, and the larger network of amateur operators around the world, may well be hobbyists, but train and operate so that they may serve their communities in a professional, if unpaid, manner.

While we typically enjoy the work, traffic handling is not a hobby: it is a public service. Once we make an appearance and volunteer in a traffic net, as part of Amateur Radio Emergency Service (ARES), or put our radio to work for a Community Emergency Response Team (CERT), we are not hobbyists: we've committed to help to achieve a mission on behalf of the public.

COTN is a training net, and we encourage all regardless of experience to join us and to learn how to put the art of radio to good use. We're happy to help you along the way so that you can see whether this is the kind of public service you'd like to render, and if so, how you can be the greatest asset you can be in a time of need. We encourage all to follow a few guidelines:
  1. Learn to operate well.
  2. Keep proper logs of operation.
  3. Track your traffic, using the "Received" and "Sent" parts of the Radiogram.
  4. Handle your traffic in a timely manner.
  5. Perform your duties professionally.
  6. Report your activity.
We're here to get the job done, and to help others learn to do the job well. Never hesitate to ask if you have a question. Once we're finished with the ongoing operation we're happy to take the time to discuss what you've seen and heard, and to find out how we can improve. Thank you for all that you do to advance amateur radio and to provide service to your community.

FEMA Emergency Management Institute Online Training

posted Mar 26, 2017, 4:12 PM by C. Matthew Curtin   [ updated Mar 28, 2017, 4:31 AM ]

COTN has started to keep track of FEMA/EMI coursework that our operators have completed. We'll need this for representing to served agencies such as Franklin County Emergency Management & Homeland Security.

All FEMA independent studies can be accessed at
Please note that a FEMA STUDENT IDENTIFICATION NUMBER will be required for any credit or documentation. (You can get one online if you do not have one.)

Once you have completed any FEMA course and have your EMI certificate, please send a copy of your certificate to the ARRL Ohio Section and Franklin County Emergency Management & Homeland Security, who keep the certificates to show evidence of completion. Please also advise our Personnel Officer by radiogram, who can update the roster. These qualifications will be needed for emergency deployments.

 ARRL Ohio Section Jim Yoder W8ERW
 FCEM&HS Chris Williams
 COTN Personnel Officer Chris Miller KD8PSD 

How Do We Count Interrupted Net Sessions?

posted Aug 30, 2016, 5:45 PM by C. Matthew Curtin

Most of the time, reporting for a net is pretty straightforward. Net managers track how many "sessions" the net holds during the course of a month. COTN typically has one session per day, but may have special sessions as well during recruiting events, training, or the annual Simulated Emergency Test (SET). Some other nets meet more or less frequently: the Ohio Single Sideband Net, for example, has three scheduled sessions daily. Every time that a net control station calls a net session and directs the frequency, the net has a session to be recorded and reported. Each station that checks into the net will count that checkin for station activity reports (SAR) and the public service honor roll (PSHR).

Sometimes, though, a session can be interrupted. Sometimes sessions get interrupted because the net control station disappears, as happens if working from emergency power and having batteries give out. In other cases, a repeater might stop working. In still other cases, interference require that the net move to an alternate frequency.

No matter what the cause, if a net session is interrupted and needs to be continued, the session ends with the interruption and an entirely new session is called on the alternate frequency. Net control will begin a completely new session, reading the script, and going through the process of checkins. Any traffic passed in the session that was interrupted still counts as having been passed in the previous session, so it is not to be listed again. Any traffic that was listed or has since come in to be passed will need to be listed for the new session. Net control will direct the traffic as usual. In such a case, the net control station of each session will create a session report: one for the session that was interrupted, and the next for the session that was called to take care of unfinished business from the interrupted session. In such a case, of course, the net session report for anything other than the 1915 ET net will have an extra word in it, indicating the time that the net was started.

For example, if the usual session on August 30 started at 1915, had eight stations checkin, passed one piece of traffic to the Section Net Liaison KD8TTE, and ran until 1921 before needing to restart, the session report would read:

 30 8 1 6 KD8TTE

A second session starting at 1925 to continue the net operation would also need to be filed, with its word two indicating the time that the net began. Suppose nine stations check in, KD8TTE as SNL, two pieces of traffic move, and the net completes at 1941. That session report would read:

 30 1925 9 2 16 KD8TTE

Of course if on the same net WA3EZN also acted as SNL, the session report would read:

 30 1925 9 2 16 KD8TTE WA3EZN

If your station checks into both nets, you will count two net checkins for SAR and PSHR purposes. If you check into only one then you will count only one. Despite the fact that the second session exists to complete unfinished business, it is a completely independent net session, just as if it were held on another day entirely.

Having Trouble Delivering Traffic to Rural Areas by Phone?

posted Aug 26, 2016, 12:34 PM by C. Matthew Curtin

Sometimes traffic handlers will have difficulty delivering traffic by telephone. FCC reports that these are happening frequently in some places as a result of some phone service providers using third-party call-routing services designed to reduce fees associated with completing calls. Sometimes those services fail to complete the call at all, which can be evident from conditions like:
  •  Ringing and ringing (10-20 times) with no answer or connection to voicemail
  •  Ringing that finally terminates with a busy signal
  •  A dead connection, with no sound, for a long time, that might end with a busy signal
To deliver traffic, you might want to try making the call from another provider, e.g., a landline if you're using a mobile phone to complete the call, before servicing the message back to the station of origin. Of course you might also consider delivering the traffic by hand or by mail.

For more information on the problem and what to do about it, see FCC's page on rural calling completion problems.

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