Guest Post: Watch Your Tone

Many thanks to Matt (W6CSN) who shares the following post  from his blog at W6CSN.Blog:

Watch Your Tone

by Matt (W6CSN)

In this modern era of radio technology, where even analog radio is largely digital, we amateurs are accustomed to perfect signal quality all the time.

Nevermind the perfunctory 599s that are handed out during contests, for activities like Parks On The Air and Summits On The Air I believe most of us like to send and receive an honest RST report.

R-S-T from the 1938 edition of the ARRL Handbook

Although subjective, readability (R) and signal strength (S) are pretty well understood quantities. But what about tone, the T in R-S-T ? When was the last time you sent or received a tone value other than “9” (the highest value) ?

Last evening, at the end of one of my frequent activations of the Presidio of San Francisco (K-7889), I struggled to pull a barely readable and very weak signal out of the noise. For what it’s worth, the natural noise floor was very low, with the geomagnetic field listed as “Inactive” on

One of these stations had a distorted signal ?

What made the signal particularly difficult was that it sounded quite distorted. The problem I faced was how to tell the OM that it sounded like his signal had been through a blender. The numbers in the Tone scale go from 1 to 9 but I did not have any understanding of the specific defects encoded by the scale. I needed to send a report, and quick, so I dashed out a “225” followed by “DISTORTED.” But I was unhappy that I needed to send an extra, unexpected word to explain the reason for the “5” tone.


1–Sixty cycle a.c or less, very rough and broad.
2–Very rough a.c., very harsh and broad.
3–Rough a.c. tone, rectified but not filtered.
4–Rough note, some trace of filtering.
5–Filtered rectified a.c. but strongly ripple-modulated.
6–Filtered tone, definite trace of ripple modulation.
7–Near pure tone, trace of ripple modulation.
8–Near perfect tone, slight trace of modulation.
9–Perfect tone, no trace of ripple or modulation of any kind.

When I got home I resolved to refresh my knowledge on the R-S-T system so that I could have it at my disposal while operating and on the rare occasion when a tone value other than 9 is warranted.

May your signals always be strong and pure.

73 de W6CSN

11 thoughts on “Guest Post: Watch Your Tone”

  1. Thanks Matt for this reminder that honing our skills in this wonderful hobby of ours never stops.

    Teri KO4WFP

  2. Brings back memories from when we used the “T” more often 🙂
    I think we also used to add a letter for things like “chirp” and “click”.
    It’s surprising that the descriptions should still focus so much on AC filtering. Most of the distortion I hear is more likely due to propagation issues.
    Ah, here, wikipedia has some good additional info:

    1. C is used for Chirp and X is used for Clicks. Use as required to prevent them gg out of use! They were used a LOT more in the 70s when USSR and Eastern Block TXes were vy prone to both. X was used because ‘clix’ was short form, which then was further reduced to X. A lot of modern rigs deserve an ‘X’, but was very distinctive in the FT-1000 Yaesu rigs, pre-modification. Heard a newer Yaesu deserving it the other day…….

  3. We all know that when a guitar or violin is tuned, it sounds all the richer and sweeter. I play a ukulele in a hurricane.

    Part of the intent of a proper RST report is to inform the transmitting station of their transmitted signal so they can make adjustments if possible. With QRP equipment, afield, you can’t. Still, it’s nice to know…

    I’ll confess my RST field reports trend ‘599,’ and in haste afield.
    S/POTA, due to the exchange, brevity, and cadence, is hasty.

    Personally, and/or in addition, I’d like to know Wx, Rig, or Op and open things up alittle. It seems just as relevant, don’t you think? So, when things are quiet or slow, I’ll key just such a question.

    Thanks Matt.

    72 de W7UDT

    1. Hi Rand,

      I agree that POTA qsos should, if possible, tend to the more casual style. I guess you just have try to read the situation and operate accordingly.

      Although, I believe honest reports are always appropriate, even if largely subjective.


  4. Just saying, I try to always give honest reports particularly for Tone. Otherwise you are doing a disservice to the sender. That said, RST, in my opinion, is very subjective and can be strongly influenced by the receivers equipment – all of it from the antenna to the headphones or speaker. Consider difference between a signal heard through a Trusdx tiny speaker vs. a highly processed IC-705. (These radios are just examples not criticisms). So I report what I hear realizing my equipment may be influencing what I hear. In fact I hope it is.
    Pete WK8S

  5. I agree, Matt, I try to always give an accurate (to my ears) report, and I get a lot of them in return. Good point about reporting tone, though. I think the scale is basically unchanged from the 1920s or 30s when R-S-T was introduced, and power supply filtering was just coming into use. Maybe time for an update? I’ll talk to my director and section manager about that the next time I see them (fwiw).
    Pete, you have a good point too, about the subjectivity of it all, and its (partial) dependence on receiving station equipment.

  6. Back when the ice was cracking, as my adult children explain my life when I was younger, a tone issue was more common, or what define as a tone issue. Chirps and clicks were common. I used the “t” for reporting that. I was amused by a chirp a few days ago. But I forgot how I used to report it.
    POTA and SOTA are relaxing, non-contest-type events. Why we use the “WARC” bands. An honest signal report is helpful to me, and adds a more human touch to the exchange. A brief, 15 second personal comment also adds fun and enjoyment. As with most of life, enjoy the journey.
    SOTA and POTA are about, for me, getting out of the house. Playing radio on the beach, overlooking the seashore at sunset, having a pleasant walk/hike, even a bushwhack, listening to the birds, watching plants grow and change with the seasons, enjoying the views, and then getting to the activation spot to make a few qsos.
    I still need Vermont, Maine and New Hampshire for hunter WAS. It will happen, some day. I am having fun in the process.

  7. Amen to all, though I do enjoy poor tone in OMs who are using vintage or homebrew equipment. A little chirp or reediness around the edges in those moments makes me smile. Truth is, I jump on any signal that sounds different on the air.

    At the same time, I think we all know how annoying a loud, painful click is on key-down. These days I monitor my signal on Web SDRs when I’m at my desk, and it’s very informative now that my ops are all-kit.

  8. With todays modern rigs we do not hear a tone other than a 9. But with the older tube rigs one often will hear chirp. Do dont forget about the chip with a C after the RST. Usually caused by the transmitter changing freq slightly when the rig is keyed. Key clicks, caused by to fast of a rise of the CW signal, and indicated with K after the RST report. Most modern rigs allow for the rise time to be adjusted in a menu. I give real RST report. Hate it when I am running 5W and get a 599, most of the time is bogus report especially when the other end says please repeat all. 73, ron, n9ee

  9. As I always understood it back’in the day’ when we using tube rigs ‘K’ at the end of RST was for key clicks and X was for crystal controlled rigs. I have a Conar novice transmitter that definitely has a distinctive ‘note’. (whoop whoop) when I fire it up.

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