Give us a Choice with the S Meter

  • 4
  • Idea
  • Updated 10 months ago
  • Not Planned
Flex S Meter - I'm sure there are many users that would appreciate the ability to have the S meter work as it does in a traditional analog receiver.  The S meter counting empty FFT bins and so forth is fine, as is the receiver being a perfect spectrum analyzer.  That aside the ability to use the S meter as a relative indication of signal strength has been a long held tradition.  So how about a software switch to allow the end user to do this?  50 uv makes S9, kick in 30 db of preamp and the meter reads S9 +30, with 0 db preamp and the antenna disconnected the S meter reads S 0.  Allow the end user to have an S meter the way S meters have worked for decades, not as a precise measurement tool, but a relative reading as it has been with Collins, Yaesu, Kenwood, Icom, and so forth.  I am proposing a software switch to allow the user to have either the "Flex" (so called) precision S meter, or a traditional S meter as the user so chooses.  Any hurrahs here! ??  Come on, I certainly can't be the only one irritated by this!
Photo of Rex K0KP

Rex K0KP

  • 44 Posts
  • 3 Reply Likes

Posted 1 year ago

  • 4
Photo of James Del Principe

James Del Principe

  • 306 Posts
  • 45 Reply Likes
Jay, I'm curious why you chose the xverter input and not the normal antenna?   Some advantage to that?    What would your results have been using Ant 1 and a reasonable SSB bandwidth like 5.6 KHZ?     Under your present conditions, what does the noise level sound like in headphones?    Regards, Jim
Photo of Jay / NO5J

Jay / NO5J

  • 1674 Posts
  • 262 Reply Likes
Bill

Yes, all of those measurements were done using LSB on 40m at @ 7.168 MHz and all done with a manually set 500 Hz LSB filter width. While I was working on it I noticed during one of the measurement that there was a very low level signal spike visible just emerging from the noise floor. so I moved the slice just enough to remove that from the filter passband, so that all the measurements wer done on a signal free portion of the noise floor.

    #FlexRadio IRC chat

For real-time discussions

        SDRgadgets

User created documentation.
           Volunteer!!

         73, Jay - NO5J

(Edited)
Photo of James Del Principe

James Del Principe

  • 306 Posts
  • 45 Reply Likes
Great follow up, Jay.... Now I will have to see if I can duplicate your numbers....   I just can't get my head around seeing S3 or so with no input because that means it is internal noise.....   Yes, it may be reading empty bins but that still adds to the noise floor and therefore defines the weakest signal that can be heard.... OK, off to the shack.       Best 73, Jim
Photo of Ken - NM9P

Ken - NM9P

  • 4239 Posts
  • 1351 Reply Likes
The S-Meter was never designed to be a "relative signal strength meter" from which users get the numbers for their RST reports.   (BTW:  The RST system was created LONG before anyone had S-meters) From a very early point, it was designed to be a calibrated signal strength meter, from which users can make precision measurements when doing antenna experiments, etc.

The S-unit is a calibrated measurement.  Each S-Unit is 6 dB stronger (or weaker) than the next one.  The "standard" calibration agreed by the engineers was 50mV at the antenna = S9.  in modern terms, this means -73 db down from a milliwatt = S9.  if you work your way down from that by 6 dB steps, you get to where your MDS is, or the noise floor of your receiver, or the level of antenna/band noise at your station.  (Note the graphs posted above) 

Somewhere along the way, various manufacturers began to boost the numbers of their S-Meters, or failed to calibrate them in sync with their preamps, so that a station that by measurement is only an S9 will register S9+20 dB whenever the +20 dB preamp is engaged.

This "S-Meter bloat" lead to a misunderstanding of the true meaning of S-Meter readings, and also lead to a type of "S-meter envy" where people actually compared their bloated signal strength readings on the same station as a way of bragging that "My rig is more sensitive than yours" because of a higher S-meter reading.  (This was very prevalent on 11 meters in the 70's and 80's)

Now with the advent of SDR's and especially the Flex, we have a lab-quality, precision instrument that is calibrated, and synced with the preamps so that the S-meter reading is always true, and therefore helpful in giving actual comparitive readings when adjusting equipment, antennas, etc.

It wouldn't make any sense to me to dumb it down so that it is a lying S-meter like many of us had in the old CB days.


Ken - NM9P
Photo of Robert Hicks

Robert Hicks

  • 3 Posts
  • 5 Reply Likes
Ken, fingers got loose again. Should have been 50uV not 50mV :). As we used to say, the S-meter accuracy on some of the earlier RX were inversely proportional to the physical size of the meter itself! In SSB was it peak or average? Depends on the AGC time constant. When S-units originated, there was only AM, FM, and CW in general usage and only AM and FM really leant themselves to “meaningful” S-unit reporting. S-units are to my knowledge, not used anywhere but in amateur radio.
Bob W5TX
Photo of Ken - NM9P

Ken - NM9P

  • 4239 Posts
  • 1351 Reply Likes
Yeah. I knew the mV wasn’t right when I read it in the return email. But by then several others had typed other comments. But then, I once had a receiver that it seemed to take about 50 mV to reach S9! It was deaf as a post!

In late 1977 I had a surplus R392 that I used for CW practice while preparing for my 13 WPM General test. If I remember correctly, it had a meter that read uV and VU units, selectable from the AGC or the Audio output line. (It has been a while). I loved that receiver. It was my first general coverage “digital” receiver. But I got blisters on my thumbs changing the heavy band switch 1 MHz at a time...chunk, chunk, chunk. Going from 10 Meters to 80 was literally a pain.
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes


The above graph probably explains why you are seeing S1 because the MDS is around -120dBm without the preamp.

Photo of Jay / NO5J

Jay / NO5J

  • 1674 Posts
  • 262 Reply Likes
Howard

Yep, I'm some where between quiet rural, and rural. We have dirt roads, but no post office delivery, We're not off the grid, but mostly off road. Except for the buzzing insects it's pretty quiet, both RF and AF. 

    #FlexRadio IRC chat

For real-time discussions

        SDRgadgets

User created documentation.
           Volunteer!!

         73, Jay - NO5J

Photo of Craig Williams

Craig Williams

  • 222 Posts
  • 69 Reply Likes
Why do we need an S meter? From what I hear everyone is always 5 by 9.
Photo of Thomas NE7X

Thomas NE7X

  • 57 Posts
  • 11 Reply Likes
I personally would enjoy being able to select between a bar graph and the old style simulated mechanical style S-Meter on the 6400M TFT display. My ICOM IC-7700 allows me to do this. People who don't want the analog style S-meter don't need to select it. Simple
Photo of spopiela

spopiela

  • 82 Posts
  • 10 Reply Likes
Flex should add the old tuning eye indicator as an option too!
Photo of Jay / NO5J

Jay / NO5J

  • 1674 Posts
  • 261 Reply Likes
Jim
 
The S-3 reading on an open disconnected ANT input, is a consequence of the open jack. the SO-239 is acting as a very short, totally mismatched antenna. A quiet termination, is required. A 50 ohm composition resistor in a BNC terminator, is a lot quieter, even a 50 ohm Cantenna attached thru 3, 5 foot pieces of RG8X, and a couple of Ant switches, is a lot quieter than an open SO-239. A shorted SO-239 is also not a matched quiet termination. but it's still a very short antenna.   

    #FlexRadio IRC chat

For real-time discussions

        SDRgadgets

User created documentation.
           Volunteer!!

         73, Jay - NO5J

Photo of WQ2H - Jim Poulette

WQ2H - Jim Poulette

  • 122 Posts
  • 29 Reply Likes
They're not perfect, but these do often work for a variety of situations.

73 Jim, WQ2H
(Edited)
Photo of Ted, NX6C

Ted, NX6C

  • 83 Posts
  • 32 Reply Likes
Thank you google image.  :-)

Photo of James Whiteway

James Whiteway

  • 1026 Posts
  • 292 Reply Likes
I want one!
Photo of spopiela

spopiela

  • 82 Posts
  • 10 Reply Likes
Wouldn't that be a hoot ... The eye is not an s meter but you could switch it in to tune the Flex when you switch to the analog S meter that some of us want. ;<) It would put Icom out of business!
Photo of Sergey Abrikosov

Sergey Abrikosov

  • 274 Posts
  • 37 Reply Likes
With all the readings and testing, I can say that I have some understanding of FLEX approach to S meter.
However, I do not know how to evaluate the signal report of other station. Yesterday, I listened FT5000MP and Flex 6600 with switching antenna by Delta switch. Same Stations with s1-s2 on Yaesu were s6–s7 with no preamp, both at 2.1khz filters.
So, I guess I will never hear a station on 6600 below S6 or so, right?
Sergey, Kn7k
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3902 Posts
  • 949 Reply Likes
The Flex can hear things many other radios just can't hear.
Photo of Sergey Abrikosov

Sergey Abrikosov

  • 274 Posts
  • 37 Reply Likes
Did I say it cannot?
Sergey, Kn7k
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3905 Posts
  • 949 Reply Likes
No. don't be confused with the RF sampling in the FFT bins with RF from the antenna,  the FFT bins are related to the pass band width readings. so that is what your seeing. As Jay pointed out a 50 ohm antenna can show lower than the bin samples on the input.
A direct sampling Flex can hear well below the noise floor.
(Edited)
Photo of James Del Principe

James Del Principe

  • 306 Posts
  • 45 Reply Likes
Varistor, I do not believe there is a radio on this planet that can 'hear' below the noise lever except some computer mode like FT-8.     This goes for any mode that uses human interpretation like SSB, AM or CW.   Just not possible for a human to do this.    Very Best, Jim
Photo of Varistor

Varistor

  • 334 Posts
  • 74 Reply Likes
That’s precisely my point. Yet the statement that Flex radios break the laws of physics is frequently made here.
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3905 Posts
  • 949 Reply Likes
It is likely I am not being so clear about what the Flex can hear,
this is a part of a reply that Steve Hicks made.

When people talk about noise floor in ham radio they are generally talking about the noise level with a 500Hz bandwidth. When the panadapter is zoomed in to the max level, the bin size today is about 5.8Hz. This is a 19dB difference in noise from where a ham would say the noise floor is to what you can see on the panadapter. This means that the panadapter can see 19dB below what most hams would call the noise floor. Your ear and brain are also able to hear below the noise floor in 500Hz because of how they work. But there are limits to how well you can hear. If you've ever worked JT65 or another long-term integrating mode, you have noticed that your computer can copy signals that you cannot hear. 

And
How it possible that the panadapter is so much better than PowerSDR?  The thing about PowerSDR is that it does only one FFT at the sampling rate you have selected.  So let's say that you are at 192kHz sampling rate in PowerSDR.  The bin size will always be 23.43Hz.  When you zoom in, you are just spreading the bins available over more pixels, but you get no better resolution...  Since we can see down to 1.46Hz bins in SmartSDR on a FLEX-6700, we have a 12dB visual advantage over PowerSDR.  The panadapter literally sees 12dB further into the noise.  By always adjusting the sampling rate in SmartSDR, we can keep showing you better and better data in the panadapter and also allow you to see wide bandwidths when you want to.
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes

@Rudy

It's a confusion/conflation of terms...

Noise Floor is as per the chart I posted above- the Atmospheric and Urban Noise at a particular Frequency... say -110dBm (about S3) @14MHz at my so called Suburban House near a mountain top near 18 TV Towers

Minimum Discernible Signal (MDS) is the weak signal that a radio can copy in a perfect environment - say -120dBm (about S1) at 14MHz with the preamps off.

So technically the Flex can hear below the Noise Floor by 10dB at my house without preamps and by 30dB with Preamps ON (about S-2.5)

However you are 100% correct, that no one will actually copy any signals below the Noise floor unless they are using a digital mode such as FT8 which can do.

So to misquote Sherwood a bit.. All modern radios hear far too well.


That said.. I have a great laugh every time someone quotes that a K3 will copy weaker signals (0.02micro volts = -140dBm) than a Flex especially since the Noise Floor on ALL HF Bands NEVER gets below -132dBm - so it copies 8dB of Noise


Photo of James Del Principe

James Del Principe

  • 306 Posts
  • 45 Reply Likes
OK, Howard, you and a few others seem to know a great deal about the operation of the Flex so I have a basic question that has me puzzled by the display of my 6500. I have owned this for some time but still don't know how to explain it.
In a nutshell, the 'S' meter in DBM does not match the level on the panoramic display with regard to noise floor. Just for example, with the antenna shorted and 6 KHZ bandwidth, SAM on 80 M, the 'S' meter reads -105.5 DBM but the average noise displayed is 130 with no preamp. With +10 DB preamp, the dosplay says 140 and with +20 DB preamp it is 150. This happens without regard to mode and selected bandwidth. It holds true for SSB at 2.7 KHZ bandwidth as it does for CW at 400 cycles bandwidth.   So first, why do the values not match and second, why would the apparent noise floor seem to drop?   The sound of the noise in the receiver does increase with the addition of the pre-amps.     Jim
Photo of Adam Farson

Adam Farson

  • 3 Posts
  • 1 Reply Like
Next time you take an inter-continental flight, ask permission to tour the flight deck. If this is granted, take a look at the HF COMM panel in the CMU (comm management unit) above the pilot's and co-pilot's chairs and tell me where the S-meter is.
73, Adam VA7OJ/AB4OJ
Photo of James Del Principe

James Del Principe

  • 301 Posts
  • 44 Reply Likes
S meters, we can all agree, are only on ham gear. All the time I worked at Sylvania Gov't Systems, I never once saw an S meter......nor my time in service with PRC-53s or GRC-46's......  who would have cared.???    but we in the ham community have had them in one form or another since the 30's so I guess they are here to stay.  How else could we give a DX station 5 by 9 when he is just above the noise level???   73, Jim
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes

I guess for some people, the fictitious reading of an Analog S-Meter gives them great comfort when reporting a signal to their "Good Buddies" 

But if you ever work me and ask for a signal report, I will give you a real one by just looking at my Panadapter and report that your signal is hitting -63dBm (S9+10dB) or whatever it really is in dBm..

Realistically No one really expects a S-Meter reading other than 59 or 599 anymore.. and no one has asked me for a real reading in probably 5+ years except when we are playing with new antennas.

BUT Analog Meter can be pretty Eye Candy to match the spark gap transmitter and magic tuning eye on the corner self.

Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3902 Posts
  • 949 Reply Likes
@visitar, I agree with you. The way Flex does it is the standard witch all Lab equipment uses. as Steve Hicks says.  I don't know if that is right or wrong to have a ham radio work in this manor. And it confuses the hell out of customers that are not so inclined to read up on it. Flex brought SDR to ham radio in the first place, who am I to question? I'm just explaining to some folks how their Flex radios work in this regard as the question crops up time to time.

Almost all contacts I make out side of contesting people ask and give signal information. It is the standard to find out how our stations are working, witch is sort of silly considering our signals rely on propagation...anyways
Photo of Varistor

Varistor

  • 334 Posts
  • 74 Reply Likes
This is not the standard for lab equipment. Lab equipment is measured and calibrated to compensate for the built-in error of the piece of equipment. So if Flex were lab grade, the noise profile of each and every radio would be captured and removed from the FFT calculations. In other words, just like the 7610, the S meter would read 0.
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3902 Posts
  • 949 Reply Likes
@Varistor..lol you are really having trouble wrapping your head around around this stuff,,don't worry your not the first one...
All spectrum analizers read RF the same way the Flex does.

I know you think Steve Hicks is wrong and misinformed, lets just leave it at that. This is the way the Flex works thank God.
(Edited)
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes

@Rudy

Do you really believe that when the IC-7610 Reads its Fictitious S0 at the antenna input when it is shorted then it is actually reading by IARU definition -127dBm (0.1microvolts @50 ohms @500Hz BW)?

Photo of Rex K0KP

Rex K0KP

  • 44 Posts
  • 3 Reply Likes
@Howard

Geez already, all readings are approximations, best guesses, estimations, and all are relative!  And yes quantum physics does work here, we are trying to measure electrons, those elusive little critters that have been proven to be able to be in more than one location at the same time - bi location.  They can also become entangled, traverse time, transfer information faster than the speed of light, and so forth.  Check out "Measurement in Science" a hard read concerning the philosophy of measurements.  The fact is our collective understanding of the universe is so lacking that we don't even know what we don't know.  We can't, except to measure something relative to something.  I posit the relative analog S Meter reading is just as valid as any other relative measurement made digitally.  But because it is relative doesn't make it not useful.  I posit that all measurements are fictitious, some might be a little closer to the truth than others.  If there even is real truth and real reality.  Do we even know what those two things are? 

https://plato.stanford.edu/entries/measurement-science/
(Edited)
Photo of Robert Lonn

Robert Lonn

  • 379 Posts
  • 132 Reply Likes
I decided to make my own S-meter, calibrated, for my Icom IC-R8600.. Total cost about $5.00.. Icom gives you an output on the radio for an analog meter,, so do others as well.. The meter is S-9 when at the 12 o'clock position as shown in these 2 pictures.. With all this S-meter talk of late, it would be nice if Flex could make the software display an Analog Meter rather then a Bar type meter.. I have plenty of radios with S-Meters to play with if I get the urge to go analog, like on my R-390A... Heathkit Meets Sharper Image!! :-)  And the meter is illuminated with 3 blue LED's... Looks cool at night!


(Edited)
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes


Here is the WOODBOX SMeter on my 6700

Looks cute.. I already posted a link but here it is again

https://www.dropbox.com/s/223si9ks962n1av/Smart%20S-meter_V1.6.zip?dl=0 


it will do almost what you want like the swinging needles except give you the fictitious readings so many hams wish they had.

Photo of Robert Lonn

Robert Lonn

  • 379 Posts
  • 132 Reply Likes
Howard, I downloaded the software and set it up, however it does not look correct on my screen like yours, the image and check boxes are messes up and oversize??? Any ideas?? I run Windows 10.

Robert
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 3901 Posts
  • 949 Reply Likes
Robert, must be a resolution problem,,but I'm not sure how to fix that. Can you change the resolution to something then change it back,,it may correct it? Perhaps un install the meter and re installing it? it must have not installed correctly.
(Edited)
Photo of KY6LA - Howard

KY6LA - Howard, Elmer

  • 3763 Posts
  • 1621 Reply Likes
Resolution or scaling issue in your windows screen setup.
Photo of Robert Lonn

Robert Lonn

  • 379 Posts
  • 132 Reply Likes
SSDR software and other programs look perfect on my LG Monitor and on my Laptop,, so I dont think I need to change anything,, but might try that on my laptop... This is the first ever program that has done this in some 3 years... The S meter is neat, but not something I must have...  I may uninstall the program and try a few things... But appreciate the feedback.

Robert
Photo of Neal Pollack, N6YFM

Neal Pollack, N6YFM

  • 252 Posts
  • 127 Reply Likes
WOW, lots of passion on this thread :-)
I never knew the idea of an S-Meter was so important to so many people.
To me, it is far more important to be able to make the QSO, or hear the weak
DX on SSB, than to stare at a meter all day   [which by nature of how many different
manufacturers are doing it differently, is a "Meaningless Index of Performance" meter.]

SO, if I go "key down" broadcasting a carrier, and 10 different people in different locations are receiving me
with different model/brand rigs, different antennas, in different locations, each one will report a different reading.   Even if they were all lined up in the same field with their different rigs and antennas, they might
well each read different.   So what use is that?    If they heard me at all, I am in their log book.  If not, I really
don't care what the reading was :-)    And if they did log me, again, I really don't care what the reading was :-)

And furthermore, as some previous poster pointed out, if you happen to work a contest, all the logged entries look like 59 to me, I have rarely seen different, since people are moving so fast to log contacts they don't seem interesting in staring at a meter long enough to analyze, should this be a 55 or a 57 or a 54???

Are we perhaps getting all tangled up in measurebating, when it might be far more fun to make contacts?

Cheers
Photo of James Del Principe

James Del Principe

  • 304 Posts
  • 45 Reply Likes
Neal, my 45th anniversary RS Camaro has a cluster of gauges on the console for engine temperature, oil pressure, Transmission temperature and voltmeter. I could not possibly go for a spin or to the grocery store without that essential data.  Same for the 'S' meter.    HI HI       73, Jim
Photo of Rick Hadley - W0FG

Rick Hadley - W0FG

  • 601 Posts
  • 130 Reply Likes
I find signal reports absolutely meaningless unless I'm engaged in a real ragchew and one of us want to compare signals with different antennas or amp on/amp off and in that case, it's extremely 'techy' to be able to quote -dBM figures.  For logging I usually use the default of 59/599 as it makes no difference for award purposes, and years from now I'm not going to care that I landed the KH1 at S1 or S9, once the QSL has been received.
Photo of James Del Principe

James Del Principe

  • 306 Posts
  • 45 Reply Likes
All good points, Rick.   The meter is reasonably good for relative measurements, not so much for absolute values. Just think that even if it were 100% accurate, it would only be valid for that moment in time subject to propagation, antennas at each end, power levels, etc.     Jim
Photo of Michael, K7HIL

Michael, K7HIL

  • 3 Posts
  • 0 Reply Likes
Similar question. I understand the bandwidth vs S meter reading, what I don't understand is why there is a discrepancy between the S meter and the Pan-adapter values.  With an extremely narrow bandwidth (~1 Hz.) the S meter reads S1 / -123 dBm and the noise level at the frequency of interest on the Pan-adapter has peaks at ~-132 and valleys at ~-136. The difference grows as the bandwidth increases.  With a nominal SSB bandwidth of 2.7 KHz the S meter reads S3 / -107 dBm while the Pan-adapter remains the same as before.

In summary I noted that the noise floor on the Pan-adapter does not change as the band pass changes from very narrow to very wide and the difference between the two varies from ~13 to ~27 dBm.

So my (similar?) question - Why is there a discrepancy between Pan-adapter and S meter?.
Photo of HCampbell  WB4IVF

HCampbell WB4IVF

  • 261 Posts
  • 76 Reply Likes

Good question.  Here’s an old post I bookmarked to help me remember:

https://community.flexradio.com/flexradio/topics/dbm-s-meter-vs-side-scale

Just curious why these numbers are so far apart?


Steve - N5AC, VP Engineering

Official Response

Jon,

Quick analogy: Think of the signal you want to hear as a gold watch and noise as muddy water. I give you a bucket with several inches of muddy water and the gold watch in the bottom.  You can see a glimmer of the watch and know it's in there somewhere (you are zoomed out on the panadapter, the noise floor is high and you can see a signal occasionally peak out of the noise).  So you decide to see if the watch is in the bucket and you split the water between two buckets (zoom in on the panadapter).  This causes the watch to be in one of the buckets only and now you can see it better through the mud.  As you continue pouring into more buckets, 4 then 8 then 16 buckets, the water level goes down by half each time (3dB lowering of noise floor in panadapter).  Eventually, the watch is sticking out of the water and you can see exactly what it is.

You'll notice that this behavior is consistent -- as you zoom out the noise floor rises by 3dB with each zoom-out because the bucket (called the bin) has twice the noise in it.  The net-net is the amount of noise you see is dependent on the bandwidth in which you measure it.  So in order to talk about "noise floor," hams have adopted a standard.  We talk about the noise floor in a 500Hz detection bandwidth.  To measure this "official ham noise floor level," just set the width of the filter in your slice receiver to 500Hz and then read the meter.  This is roughly equivalent to zooming all the way in on your FLEX-6000 and the zooming out 6 times (FLEX-6500 or FLEX-6300) or 8 times (FLEX-6700) and then the number read along the panadapter (In reality, the bin size at this point will be ~374Hz and so the panadapter reading will be off by about 1dB).

The slice meter S-meter measures the total power of everything in the bandwidth of the slice filter -- noise and signal -- and provides this as a single power reading.

Another analogy might be to look at a pail of dirt spread across your living room floor.  If you look through a paper towel tube, you might tell your wife that the dirt level is only "a tablespoon."  Your wife wife might look at the whole room and say "No!! There's an entire pail of dirt in here!"

One final thing -- you will also hear hams say "I can see 10dB into the noise floor" or you might look at WSJT and see that it has numbers like -20dB meaning it sees a signal 20dB into the noise.  How is this possible?  You clearly cannot see a signal below the noise floor in your panadapter, right?  Well again, the noise floor is defined as the 500Hz noise floor.  What's really going on is that they are restricting the detection bandwidth (think narrow CW filter) and they they can hear the signal with less noise.  Your ears (brain) do this naturally on CW -- you can hear a single tone stick out of the noise because your brain does the equivalent of an FFT, divides it into buckets and then tells your consciousness "there's a bunch of noise but there a tone of roughly 1000Hz in there."  WSJT uses very narros bandwidth detectors and time-averaging to see "below the noise floor" but what's really happening is that it's reducing the detection bandwidth, splitting the noise into buckets and then looking for signals in the presence of less noise.

https://community.flexradio.com/flexradio/topics/s-meter-with-version-2-3-7

Please remember that you cannot compare noise read on the S-meter in the slice receiver and the panadapter noise floor because of the different bandwidths of receivers used in the slice receiver (filter) and the FFT bin bandwidth (unless they are the same based on a zoom level).
(Edited)