Error Correction

Oh bugger, I made a mistake: Correcting Errors

Recently Peter VK3WOW raised the topic of error correction on social media. Peter was seeking people’s thoughts on formal error correction versus the less formal practice used by most operators these days.

It’s a good question and worthy of further discussion. Newcomers may be confused regarding many of the informal protocols that frequent day-to-day CW operation.  This article provides context and guidance.

Peter asks:

“I would be interested to hear the thoughts of this community on the subject of error correction in Morse code sending. 

Way back in the mists of time when I first learned Morse code I understood that the right thing to do when I made an error in my sending was to send a sequence of dits (technically, 8 dits, I think) and then to resend the content that was wrong. 

Recently I have joined LICW, where I have been participating in classes where members send at 22-25 wpm in some classes, and 25-35 in another. It appears to be a convention among these (most US-based) operators that the best way to handle an error is to pause and resend the content that was wrong, but without any intervening sequence of dits to indicate an error has been made. 

The only exception to this rule appears to occur where a user has mistakenly sent a series of characters no user could be expected to recognise (say, an unfamiliar foreign word) and then makes a mistake. In this case, the user would send a sequence of dits before resending the content that was wrong.

I personally find this convention perfectly acceptable, and indeed easier to head copy than the kind of Morse interspersed with chains of error dits such as I have, until now, been sending myself.

What are the thoughts of this community on this matter?”

Summarising the responses and adding my own perspective, there are broadly two approaches to correcting errors: the formal and procedurally correct method, and numerous informal code sequences that are broadly understood by the majority of operators.

The formal procedure follows:

Official procedure

International Morse code procedure specifies:

• If the sending operator becomes aware of an error, they shall:
  1. Stop transmission.
  2. Send the error signal (ITU-R M.1677): eight dits in a row (……..). The prosign  HH.
  3. Repeat the last correct word (or group) correctly.
  4. Continue the transmission from that point.
• If the receiving operator notices something wrong after transmission has stopped, they should:
  1. Repeat the last word correctly received, followed by a question mark (?).
  2. The sender then resumes from that word

This keeps both stations synchronized and avoids ambiguity about which part was wrong.

The more common, less formal procedures are numerous but broadly fall within these three categories:

1. A few (3, 4 or 5) widely spaced dits then resend the incorrect word;
2. For a small slip, just resend the broken word;
3. If the incorrectly sent word is obvious and the QSO is informal, ignore the error as the other ops will know what you mean, and you can continue with your transmission; e.g. “wx is sunnq”

Formal message handling has its own set of protocols which are outside the scope of this article.

For me… it’s horses for courses. I’ll adapt based on the situation I find myself in. In a formal QSO or with a new operator, I will tend to use the correct protocol. However, for the bulk of QSOs, it will be one of the three informal procedures noted above.

Coming back to Peter’s questions and the context of those who replied, there was a good spread which pretty much reflected what I’ve summarized.

“I send 4, 5 or 6 slow dits, depending on how frustrated I am with the error I made”

“I probably do the wrong thing, however I might pause and then send 3 dits, then the corrected word”

“In many ways it depends on how well I know the operator I am in QSO with”, to which the response “you tend to be more formally correct with strangers, which makes good sense”

“I send a handful of dits at a slower speed to show my frustration then resend at normal speed”

Hopefully this article has provided clarification and guidance on how to correct an error when sending Morse Code. If you’re just starting out, it’s a good idea to use the formal protocol to ensure you understand and can apply correct Morse Code before deferring to informal short-cuts. If you’d like more information, please comment on this article or send me an email.