Everyone wants to know how their signal sounds on the air and often the best way to find out is a signal report from other ham radio operators. The standard signal reporting method for amateur radio is the RST (Readability-Signal Strength-Tone) system. See Practical Signal Reports on HamRadioSchool.com.
When using 2m FM on Summits On The Air (SOTA), we can simplify the signal report. Because it is a voice mode, we drop the reading for Tone and just give RS reports, so a perfect signal on voice is RS 59 or simply “five nine.” The Readability report is a number between 1 and 5, while the Signal Strength report goes from 1 to 9. (See the listing at the bottom of this article.) The signal strength generally corresponds to the S meter reading on your radio but most FM rigs have very basic meters. Some don’t provide a meter reading at all. The photo to the left shows a typical bar graph on a Yaesu FT-60. Don’t expect high accuracy, so if the meter reads full scale, give an S9 report. If it reads half-scale, that’s probably S5, etc.
On VHF FM, signal reports may also be given in terms of FM quieting. A strong FM signal is said to “quiet the receiver” since there is virtually no noise present in the received audio. As the signal strength is decreased, noise starts to appear on the received signal. At lower signals levels, the noise increases dramatically and the signal becomes unreadable. This dramatic increase is called the threshold effect, meaning that FM signals do not gradually fade out, they tend to fade quickly into the noise. The key idea here is that you want your signal to be strong enough to be above this noise threshold. In terms of a signal report, a strong signal may result in a “full quieting” report. If the signal is less than full quieting, you may hear a report like “90 percent quieting” or “you have about 10% noise”, which both describe the amount of noise present in the signal. If the signal is really noisy, the report might be “50% quieting.”
Keep It Simple
For practical 2m FM operating, don’t overthink these signal reports. If the signal is easy to hear and is full-scale, give a 59 report. If it is easy to hear but the meter reading is less than full scale, reduce the signal level report to something like 56 or 57. If there is some noise present, you might want to reduce the readability to 4, so maybe give a 44 or 45 report. (Usually, if there is a readability issue, the signal strength will also be lower.) If you are having a difficult time hearing the signal, it’s probably a 33 or less. Readability of 1 or 2 is rarely used because it indicates you are not actually hearing the other station.
One final note is that sometimes the operator on the other end is looking for a more critical evaluation of his signal quality. If he says something about “checking out this new microphone” or “have been working on solving an audio problem”, that may be the clue to spend a little extra time really listening to the signal and providing more comments on how it sounds. For most of us, we don’t actually get to hear our own signal on the air, so it’s very helpful to get quality feedback from other radio amateurs.
73 Bob KØNR
The RST system as listed on the ARRL web site, Quick Reference Operating Aids:
Readability
1 – Unreadable
2 – Barely readable, occasional words distinguishable.
3 – Readable with considerable difficulty.
4 – Readable with practically no difficulty.
5 – Perfectly readable.
Signal Strength
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.
I agree, keep it simple. Unless of course you’re helping someone sort out an audio issue, but that’s a conversation of a different color.
On the strength scale, I tend to simplify it even further and just report odd numbers, i.e. 59, 57, 45, 33, etc. Easier for me to guess on the fly and still compatible with the 1-9 scale. Maybe not all of the nuance, but close enough with all of the fading that’s probably going on at the same time as well.
I hear signal reports of “5×5” fairly often. I assume that’s equivalent to “59”, which I have yet to hear.
When is “5×5” used, and when can it be used as opposed to “59”?
My understanding of 5×5 is that it indicates a very readable signal with an S meter reading of 5 (or S5- Fairly good signals), so not full scale.
I dug a little deeper and found that there is some non-ham usage (military and aviation) of a 5 point scale for both signal strength and readability. See this article, for example: https://military-history.fandom.com/wiki/Five_by_five
Note that this systems has signal strength first and readability second, reversed compared to the ham radio system.
More here: https://thegunzone.com/what-does-military-5-by-5-mean/
Also this wikipedia page discusses the 59 and the 55 systems:
https://en.wikipedia.org/wiki/Signal_strength_and_readability_report
I still maintain that generally accepted amateur radio usage is the RST 5-9 system defined on the ARRL website.
Bob,
I fully concur with you that when using CW, AM or SSB that the RST system be used, as long as it is used properly…… meaning that you only say “Five by Nine” when the quality is five and the meter reading on your S meter is nine!
But I completely dis-agree with its use in FM.
The RST signal reports have been BUTCHERED by many hams, especially newer hams that don’t know what RST even means.
When I operate HF, which I do every day, when someone tells me that I’m “Five by Nine” I have to ask them if I’m actually “S9” on their meter. And they come back to me telling me that I’m “S6” or whatever other than “S9” because they think that “Five by Nine” is nothing more than a general acknowledgement!
I know that a lot of this comes from contesters who use logging software, as 5×9 is an F key and you have to manually type in something else. Shame on the software writers who created that!!!
Lets get everyone to learn what RST really means and to only use it on HF or other bands where the mode is CW, AM or SSB and teach them to use “Levels of quieting” for FM ops.
Or to simply say “Loud and Clear”, “Slightly Noisy”, etc. when operating FM.
73,
Doug WB7TUJ
Hi Doug,
OK, so we agree that Five Nine means good readability and S9 signal.
But you “completely dis-agree with its use in FM.” Now why is that? The concept of readability is still valid and we can also provide an indication of signal strength. (As the article says, most FM rigs do not have great S meters, so that is a bit of a limitation.)
Then your comment says “The RST signal reports have been BUTCHERED by many hams, especially newer hams that don’t know what RST even means.” I agree with that, too, which is why I write articles like this. I am in favor of accurate RST signal reports on all modes, including FM.
I am also fine if people want to say “full quieting” or whatever. This is very appropriate in a repeater system where the received signal level is from the repeater transmitter. This article is about 2m FM on SOTA, which is always simplex, no repeaters.
73 Bob K0NR