Looking at amateur radio forums and email threads, oftentimes amateur radio operators will use "73" or "73s" where one might otherwise expect to find "Sincerely" or "Regards". Why?

up vote 31 down vote accepted

The usage of "73" for such a purpose comes from the Phillips Code, originally devised in the era of telegraphs to speed up transmission of common messages by mapping them to numbers.

"73" mapped to "best regards" or "my compliments" and was intended as a general valediction for transmitted messages.

It is still used for that purpose today in morse code transmissions and often makes its way into everyday correspondence among hams as a form of jargon.

There is also "88" (which maps to "love and kisses") that sometimes takes the place of "73" for communications between affectionate parties.

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    There's also the less-used 99 (which might be unofficial) that means something along the lines of go for a hike someplace warm. – a CVn Oct 25 '13 at 20:43

73 is, as Amber said, Phillips code for best regards or my compliments. I just wanted to add that it's redundant to say 73s, which amounts to Best Regardses or My Complimentses. This puts one in mind of Smeagol, talking to Hobbitses.

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    Welcome to the site! Just a side note - since this is mostly a side note to an existing answer, it might work better as a comment. :) – Amber Oct 29 '13 at 23:04
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    I wanted to but wasn't sure how to go about it, there wasn't a spot for it. – Marcus Oct 30 '13 at 2:02
  • Ah, yeah - I forgot that comments require a (very small) amount of rep to be able to add them. Consider it a note for future reference once you get the ability. :) – Amber Oct 30 '13 at 4:00
  • @Amber Dunno how it was in '13 (Were you a mod then?) but you could convert it. This is kinda reminiscent of people who say "PIN Number" or "ATM Machine". – Iszi Nov 5 '15 at 0:03

Most of these things come from morse code. They were used because they have a distinctive and musical signature, listen to the rhythm of '73' some time. Rhythm was (and should still be) the mark of a good operator. Alas, some non military operators in the early days were not, that is where 'ham' came from: because the operators sounded 'ham-fisted'. When I was a young boy my navy father taught me an exercise for learning rhythm it is: best bent wire / g Try it out some time on your morse key, you will be surprised how it improves your musicality.

If I say best regards to you it would be 73. If I and in a group or a net there are many people hence 73's, plural. It originated from code, person to person, singular. IMO, best regard(s) , Jerry W5JRY

  • I might add that I have heard (often) 73s (plural) on SSB (or, even in written form) but I have never heard it on CW. That is, 73 followed by the letter s. On CW, it is not unusual to hear 73 repeated, as in 73 73, even when band signal quality does not require repetition. – K7PEH Sep 14 '15 at 0:35

See a list of jargon here: https://www.qrz.com/page/hamspeak.html

73 de TF8HA

On morse code you want your transmissions to be as short as possible and so they have developed codes for frequent words or phrases. 73 is the code for best wishes, sincerely, etc.

protected by Kevin Reid AG6YO May 17 '17 at 2:51

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