RST, you know, that 599 thing that you have programmed into a macro to send to the other station during a contest. Today it seems it is just a formality to complete the contact, because without it, some stations won’t log you. It is a required part of the exchange for a two way contact to be valid. “It’s just a number.”

Actually, no, it is not just a number. It is your way of telling the other station how he is being heard where you are and a means to pass along a bit of valuable information to them. Readability, Strength, and Tone. The first two digits are an indication of the propagation between you and the other station. The last digit, Tone, can be used to tell a station he has a signal problem he should investigate.

This last week I gave Honest RST’s ranging between 119 and 599, and I also sent out 577, 335 and 331. I followed up with an email to tell them what I heard. The first station was already aware he had a problem, “only when I use my amplifier”.  He did not indicate if he’d try repairing or correcting the problem though.

Another thought it was odd he received a poor Tone report and checked his signal...

“You are right: a check with a spectrum analyzer shows that the amplifier is the culprit. Long time since I used the linear at all, always using just the transceiver. I guess some component went bad during the last year or two. Your warning has been very precious and I thank you very, very much for having taken the time to sending me an email.”

The third one was totally unaware his signal was a close relative of an electric fence. Not only was it terrible, but it was also 10-12 kc wide and full of spurs.

The exchange of RST is more than a formality. It is exchanging information. An honest RST is a wonderful thing. Listening to the exchanges, you might be able to tell I am hearing east coast stations well but west coast stations poorly. Yet, if I were handing out 599 to everyone I worked, yet struggling to get callsigns, you’d think I’m hard of hearing or can’t copy CW. Be honest with the stations you work, outside of contests, and give them a real RST, It is most appreciated. When I’m working USA stations from the middle of the Pacific and reporting weak to moderate signals to USA stations, but they are all sending 599 to me… do I have a receiver problem?

It’s a two way street. Please be honest.


  1. Unreadable
  2. Barely readable, occasional words distinguishable
  3. Readable with considerable difficulty
  4. Readable with practically no difficulty
  5. Perfectly readable


  1. Faint—signals barely perceptible
  2. Very weak signals
  3. Weak signals
  4. Fair signals
  5. Fairly good signals
  6. Good signals
  7. Moderately strong signals
  8. Strong signals
  9. Extremely strong signals



1936 definition

modern definition


Extremely rough hissing note

Sixty cycle a.c or less, very rough and broad


Very rough a.c. note, no trace of musicality

Very rough a.c., very harsh and broad


Rough, low-pitched a.c. note, slightly musical

Rough a.c. tone, rectified but not filtered


Rather rough a.c. note, moderately musical

Rough note, some trace of filtering


Musically modulated note

Filtered rectified a.c. but strongly ripple-modulated


Modulated note, slight trace of whistle

Filtered tone, definite trace of ripple modulation


Near d.c. note, smooth ripple

Near pure tone, trace of ripple modulation


Good d.c. note, just a trace of ripple

Near perfect tone, slight trace of modulation


Purest d.c. note

Perfect tone, no trace of ripple or modulation of any kind

If there are other notable tonal qualities add one or more of the letters AX, listed below, after the number.

Suffixes were historically added to indicate other signal properties, and might be sent as 599K to indicate a clear, strong signal but with bothersome key clicks.

Suffix code



signal distorted by auroral propagation


"chirp" (frequency shift when keying)


key clicks


signal distorted by multipath propagation


signal distorted by scatter propagation


stable frequency (crystal control)