Monday, November 28, 2011

RST - meaningful or obsolete?

There is an interesting discussion going on QRP-L with regards to the RST system.  Bruce Prior N7RR, who I respect tremendously, has come up with what he considers to be a new and better system - CSQ.  This would relate to Copyability, Signal Strength, and Quality of Signal.

As a summary, this is his scale:

CSQ Summary

C or Copyability
N = no recoverable signal*
0 = discernible but not copyable*
1-9 ≈ 10% to 90% copy
G = Good 100% copy, but short of perfect
P = Perfect armchair 100% copy or full-quieting on FM

S-Meter or Signal Strength
0 = no S-meter reading
1-9 = S-1 to S-9
A = 1 dB to 10 dB over S-9
B = 11 dB to 20 dB over S-9
C = 21 dB to 30 dB over S-9
D = 31 dB to 40 dB over S-9
E = 41 dB to 50 dB over S-9
F = 51 dB or more over S-9

X = characteristic steadiness of crystal (Xtal) control or eXcellent quality
R = AC Ripple or buzz in transmission
C = Chirp or tail on make and/or break
K = key clicKs or other Keying transients
O = Overmodulation or Overdeviation in phone or digital modes

* For Copyability reports of N or 0, no Signal Strength or Quality reports are needed.

P6O = for a PSK-31 signal: perfect 100% copy at S-6, but overdeviated
93X = for a CW signal: 90% copy at S-3 with excellent quality
G7O = for an SSB signal: Good but less than perfect 100% copy at S-7, but overmodulated
PAX = for an RTTY signal: perfect 100% copy about 10 dB over S-9 with excellent quality
P6X = for an FM signal: full-quieting 100% copy at S-6 with excellent quality

I think Bruce is on to something as RST is abused more often than not.  While I try my best to give accurate RST reports, how many times have YOU gotten a 599, only to be asked for repeats?  One of the few reasons that I can think of asking for a repeat of a 599 signal is if the XYL asks you to pick up something from the grocery store while you're trying to copy!  For those of us who can't walk and chew gum at the same time, that can be a difficult task. Other than that, if you have to repeat, you're NOT 599.

Bruce's system is more comprehensive; but also a lot more complicated.  I think the average Ham prefers the KISS quality of RST.  It's simple, easy and to the point. But the problem, as mentioned before, is that in a hot and heavy contest situation, RST is almost always abused.  599 in a regular contest or 559 in a QRP sprint is almost a given.

So what can be used instead of either?  A serial number, ambient temperature of the operator's location, birth year of the operators? Or does it need to be changed at all, with the proviso that it be truthful?  Have contesters (myself included at times) gotten so lazy that RST has lost its meaning?  Or perhaps maybe the RST part should just be eliminated for all except rag chews?

It's very commendable that Bruce is trying to come up with something new, better and more meaningful.  The bottom line, though, is that whatever system is devised, it has to be simple and easy enough to be used by a wide majority of Amateur Radio ops.  If it doesn't have that appeal and acceptance, then we're just spinning our wheels.

72 de Larry W2LJ
QRP - When you care to send the very least!


  1. Hi Larry,

    I have on many occasions pondered the logic of the almost meaningless RST 599 system.

    In my humble opinion all that is required is the Readability “R” as defined by many web sites including Wikipedia. No more and no less.


    The R stands for "Readability". Readability is a qualitative assessment of how easy or difficult it is to correctly copy the information being sent during the transmission. In a Morse code telegraphy transmission, readability refers to how easy or difficult it is to distinguish each of the characters in the text of the message being sent; in a voice transmission, readability refers to how easy or difficult it is for each spoken word to be understood correctly. Readability is measured on a scale of 1 to 5.

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

    For example: “W2LJ de ZS6A GE Larry UR R4 HW ? BK”

    73, Pierre ZS6A

  2. Hello Larry, if I could vote I would say RST is obsolete. Why should you exchange signal reports. Someone with for example a SDR with superb filtering can get almost "BBC" quality out of a just readable signal. It should be enough to tell someone "I do understand every word of you, don't miss anything" and that could be a S-1 to S-9 signal. But signal is not that important anymore. 73, Bas

  3. Good morning Larry, as for the 599 report I know for sure during contests it is something that is sent without meaning. It sure would had been nice to get some "real" signal reports during the contest to see how my 500mW's was doing....oh well the debate goes on.....

  4. I agree that the proposed new system is far too complicated, although it is a commendable idea.

    Most contest scoring does not take signal strength into account, therefore the signal strength is always automatically given as 59 or 599 because it makes no difference to the scoring.

    Having to take an accurate RST would slow your run rate in a contest. I know you know all this already but I'm just pointing it out because I don't believe the system is "abused" as such. It's just the way contest scoring is set up.

    Thanks for the interesting blog post.

    73 de EI2KC

  5. Signal reports are meaningless in this day and age - it's just a silly, useless field in every logbook or program that should have been removed 35 years ago.

    It's a hanger-on from a long bygone era but radio hams simply won't give it up.

    And there is no need for anything to replace RST.

    Given the usage of DSP and tight filtering any sort of relative signal indication is without merit - especially in a contest where everyone has their filters cranked tight. And it's usually after a large contest that we see these complaints begin to roll in again about "everyone being 599".

    It's way past time for us to GIVE IT UP!

    If a guy is barely readable then make that comment in the early going of your QSO. If he is knocking your speaker off the table then tell him his sigs are strong.

    ANYTHING else is simply made-up horse hockey using an imaginary scale for reference - I don't care how detail oriented or experienced a radio amateur might think themselves to be.

    One might as well believe in Santa Claus as to believe there is real merit in sending a 479 instead of a 549.

    Here's a test - next time you're watching TV with your family ask them each to tell you a number, from 0-9 for how loud the volume is and see how often you all agree...

    It's so goofy a notion that it makes me laugh! :-)

    73, Jeff KE9V

  6. I don't have a problem with the RST system of reporting. However I must confess to employing it in an objective manner.

    I have no confidence in the accuracy of "S" meters, and my QRP rigs do not even have them. So the gray matter between my ears makes the final decision.

    The "T" for tone report is frequently incorrectly transmitted. I think not to discourage the other operator especially if his rig is home-brewed.

  7. I posted on a simplified version of RST some time ago here

    The last thing we need is a reporting system even more unnecessarily complicated than what we already have. I consider that bad engineering.