S meter

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Always reading S-4 on 20 ,S-5-6 40. S-6 on 75 meters
RF not lowering it
Why is it always read high
Icom 7700 zero on 20 ,40 S1 average 80 S 2 Average
Now when my friends talk on different bands getting their normal S reading

Is their adjustment
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Joe Conover

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Posted 6 months ago

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KY6LA - Howard, Elmer

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Search this forum there are lots of discussions why Flex is accurate and the Icom is not correct
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Joe Conover

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Oh will do my Ten Tec Omni 7 is close to same S meter reading as 6400M
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Burt Fisher

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Search this forum there are lots of discussions why Icom  is accurate and Flex is not correct


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HCampbell WB4IVF

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Rob Sherwood on “S-Meter Accuracy” 6-OCT-2016

While no Japanese rig has a properly tracking S meter, the following do:

  Flex 6000 series

 Apache ANAN

 Most K3 and K3S, though occasionally an individual radio cannot be calibrated properly. This includes the option to have the reading correct regardless of preamp or attenuator setting.

 Orion II once Ten-Tec updated software to allow S meter calibration. Orion II does not correct for preamp or attenuator selection.

 Eagle is good, except the S meter is microscopic and I think it quits at S9+30 dB. The Eagle reads correctly regardless of preamp or attenuator selection.

 Hilberling S meter is quite good.

 ADAT ADT-200A is very good but ergonomics in general are absurd.

 Elad DUO S meter is outstanding

 Perseus S meter is outstanding.

 With virtually all current products today having a virtual S meter, there is no technical reason the S meter cannot be programmed to read properly from S1 to S9+60 over.

When an S unit is only 2 to 3 dB, it makes QSB look much worse.*

Rob, NC0B

-------------

*Note (by DJ0IP): Most recent Japanese transceivers are using just 3 dB per S-Unit. This makes the received signal look stronger... but at the same time, the QRM, QRN, and QSB also look worse!

http://www.dj0ip.de/sherwood-forest/sherwood-sound-bytes/
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Burt Fisher

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The debate on S-meters is simple, Flex applies a theoretical standard whereas the rest of the ham world applies a meaningful practical standard.

In the Flex world your S-meter could read S-4 or more even if the antenna input is shorted.
In the rest of the world if you short the antenna input S0 is the result.
Of course S-meters are hardly precision meters as antenna, propagation and other variables cause the meter to be totally relative.
 
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Joe Conover

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Burt so what does my S meter always read 4-5 with no one talking and quite band like 20 meters ?That my Question ???
It does read same S meter reading for my local contacts if they are S9 on
Icom 7700 they are S9 on Flex 6400M
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Lasse Moell

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It's bascially due to how many dB one S-unit should be (there is only a recommendation, no standard). Usually S9 means -73 dBm at the antenna input port on the radio, and most non-JA radios then set 6 dB between each S-unit. JA seems to have 3 dB between each S-unit.
Also, remember that it reflects the amount of power in your bandpass, i.e. a narrow filter will see less noise and show less "S-units".
https://community.flexradio.com/flexradio/topics/s-meter-accuracy-of-flex-and-others-rob-sherwood

https://en.wikipedia.org/wiki/S_meter




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Joe Conover

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No matter if I use 1.8 to 2.8 filter or RF gain control
Still 4/5 S units on 20 meters
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Lasse Moell

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Of course the difference of going from 2.8 to 1.8 kHz is small, it's less than 2 dB. Remember Flex has chosen 6 dB for each step, i.e. you need to go fron 2.8 down to 0.7 kHz to have one S-unit less, IF you only have noise in the passband.

One way of pleasing most users would be a user defined table, mapping the received power to shown S-units. Purists may say this is wrong, but then S-units are only a recomendation no standard. Some do get their knickers in a twist when the S-meter stays the same when invoking pre-amp, or even get crazy when the S-meter shows reduced numbers... it all falls back to lack of understanding of power, noise, noise factor and what you accually measure :)
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David Warnberg

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HAHAHAHA, lets just add more confusion..

Howard says "Search this forum there are lots of discussions why Flex is accurate and the Icom is not correct"

Next replay Burt says "Search this forum there are lots of discussions why Icom  is accurate and Flex is not correct"

HAHAHAHAHA...

I would suggest another source for your information as you can see even Flex owners can't agree..
This is an excellent read.. https://community.flexradio.com/flexradio/topics/s-meter-accuracy-of-flex-and-others-rob-sherwood


(Edited)
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Joe Conover

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CoolAid lmao time will tell
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Bill -VA3WTB

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Ted, the Flex 6400M and the 6600M are mostly in their own leage. With connectivity, Remote, and there just is no other stand alone radio with such a great panadapter,,nothing. And simple to use.

I agree it will be very hard for Icom, Kenwood, Yeaesu, to keep up with the K4.
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Joe Conover

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I’m going ask a curse word lol how about Apache labs Anan SDR do they make anything like 6600M or 6400M
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Bill -VA3WTB

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Anan has no radios like the 6400M or 6600M.
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Ted VE3TRQ

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From all reports, Apache Labs makes a fine transceiver, but I have also heard it’s a bit more like driving a Lamborghini :-) Have a contract with the mechanic, or be one - they are much more hands-on as far as configuration goes. But they really do perform, apparently.
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Joe Conover

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David

I agree

It’s not normal have 4-5 S at my area on 20 meters when

no one talking I owned at 12 different HF Radios

Yes receive ssb signals are accurate with my 6400M
I
(Edited)
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Lasse Moell

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Trying to find the specs for the 6400 receiver I failed and using the numbers from the 6300/6500. It states that -121 dBm is the MDS of the radio with pre amp OFF and 500 Hz filter. Assume you are looking at SSB, this translates to -114 dBm with 2,5 kHz BW (remember this is 6500 I do not have the numbers from the 6400). This is slightly more than S 2 accordingly to the recommended levels by IRAU. All these numbers seems to translate to a receiver NF of 26 dB, which is a bit high in my book, but real world testing shows I only need to activate the pre-amp on the higher bands, as the atmospheric noise is usually higher on lower bands.  Remember that the s/w compensate for the additional gain and the user will only see lower S-numbers if the amospheric noise is lower than the radio sensistivity. It bottoms out to if you want the S-meter to read lower numbers when you have your dummy load attached (it may read S 2-3), do invoke the preamp. You will see lowest number with the pre amp at the highest setting. This will give your receiver lowest noise factor. But it is wasted if the noise from the antenna is higher, and the price you pay is less ability to handle multiple strong signals (i.e. dynamic range).

All these numbers may be confusing for some... but the bottom line is: If you want your radio to adhere to the IRAU recommendation, you will have your S-meter showing higher than zero even when using SSB bw and a dummy load with the pre-amp off. Like it or not :)
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Lasse Moell

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Even though I use dBm when I do my own measurement using my receivers, it is still not really a meaningfull way of reporting the received signal. The proper way would be field strengh, which also take in account thé antenna used by the receiver, but that's another can of worms...  I pretty much resigned giving out "meaningful" strenght reports,  it's really either I hear them or not :)
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Duane N9DG

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"Personally I have long since stopped give S Reading to DX Stations and now only give out readings in dBm - most sophisticated DX stations appreciate the much more accurate and realistic report than the usual  59"

+1000

I tell stations who want to know there signal strength at my location in dBm too. I can't remember when I last told someone an S unit reading for their signal strength.

If the propagation path is stable, as it can often be, or a path that isn't subjected to propagation modes. Then doing back to back readings in dBm will accurately reflect the change reasonably accurately between one antenna vs. another configuration, or the amplifier on or off scenarios.

So the notion that propagation variability always makes those kinds on on air signal comparisons impossible is nonsense and is just rationalizing and a lazy excuse for accepting inaccurate signal strength metering.

Nothing more funny than hearing two stations comparing different antennas or amplifier an vs. off and then using S units to compare the differences. They do do the mental gymnastics of 1 S unit = 6dB to come up with a dB difference in signal strength, but will still be totally off because the legacy technology radios and current SDRs that emulate legacy radio technology the dB per S unit are anyone's guess.

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Duane N9DG

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"Personally I have long since stopped give S Reading to DX Stations and now only give out readings in dBm - most sophisticated DX stations appreciate the much more accurate and realistic report than the usual  59"

+1000

I tell stations who want to know there signal strength at my location in dBm too. I can't remember when I last told someone an S unit reading for their signal strength.

If the propagation path is stable, as it can often be, or a path that isn't subjected to propagation modes. Then doing back to back readings in dBm will accurately reflect the change reasonably accurately between one antenna vs. another configuration, or the amplifier on or off scenarios.

So the notion that propagation variability always makes those kinds on on air signal comparisons impossible is nonsense and is just rationalizing and a lazy excuse for accepting inaccurate signal strength metering.

Nothing more funny than hearing two stations comparing different antennas or amplifier an vs. off and then using S units to compare the differences. They do do the mental gymnastics of 1 S unit = 6dB to come up with a dB difference in signal strength, but will still be totally off because the legacy technology radios and current SDRs that emulate legacy radio technology the dB per S unit are anyone's guess.

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Dave WB7WHG

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Thanks for your comment, Duane! Good information, as always
(Edited)
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Dudley - WA5QPZ, Elmer

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Joe,

Move your receive bandwidth to 10 HZ  (yes it will go that small)  that way you are only measuring the power within 10 HZ,  you should see near zero.   It's the power of the noise with in the bandwidth.    You will also notice that the band level will drop with each additional preamp setting added,  this is correct too,  giving you a better signal to noise ratio that a conventional radio can't do or show on the S-meter.   

Dudley
WA5QPZ
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Joe Conover

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Ok I’ll try 10 HZ

I seen that below that was my next question thanks

You will also notice that the band level will drop with each additional preamp setting added, this is correct too
(Edited)
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Burch - K4QXX

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What I don't understand is why people care what their S meter says when there isn't an antenna connected to the radio.  If it's S0 or S4 without an antenna connected to the radio, who cares!  A radio without and antenna connected to it is useless.  I'd much rather have a S meter that is accurate than one that reads S0 without an antenna connected to the radio.  I have never used a radio without an antenna connected to it....

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Joe Conover

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It’s accurate just asking question
Is this computer ok use with Flex 6400M my brother gave me today
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Michael N3LI

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Should be Fine Joe. You actually don't need a lot of horsepower to run a Flex Sig series since most of the processing is done inside the radio.
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Joe Conover

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CW S-2.8-3 in 20 meters and SSB S-4
Not sure how zoom in screen yet or what + or _
Does on picture at bottom far right

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Stan - VA7NF

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Interesting how certain people always line up behind this S meter topic, and they always talk about the reading of NOISE levels.  The discussion never goes to how to measure ONE signal, much stronger than the noise, within the pass-band.  Narrow or wide it always reads the same.The wider the pass-band the more (number of) individual noise pulses are received. 
Homework: Go to WWV, narrow the filter to minimum and measure the strength of every sideband element.  Then widen the filter to cover the entire modulation and measure again.  The sum of every sideband and carrier will equal the full signal received. 
In the same way a single panadapter bin (width / 4096 bins per display) can vary from 3418 Hz per bin at 14Mhz to 0.25 Hz per bin at 1Khz.  More signal (noise + real signals) per bin will come in at a wide panadapter setting than at narrow.  Actually you should expect to see, with just background noise, a 41db (7 true S units) difference in the panadapter noise level on the dbm scale with some signals peaking above that noise level.  Zoom in and the noise per bin will drop but the individual signals will remain the same level.
 
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Michael N3LI

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It's a strange conundrum. The Flex is showing it much more accurately, but so many people are used to the terribly innacurate readings legacy radios have, and it seems like the Flex is wrong, when it is the radio doing things correctly. Takes some getting used to.
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Joe Conover

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Yes. I’m used to it now no problems
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Steve K9ZW, Elmer

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This has been discussed at length before.  

In the traditional approximations vs closer to theoretical measurement, FRS has been consistent with their philosophy of using the available technology of their platform by adopting the closer to theoretical approach.

The former compromises over time became a "availability heuristic" (basically a rule of thumb based on availability and experience, rather than correctness) but as we know were never truly accurate nor perhaps even appropriate if we're after true signal strength.  

The FRS approach plays closer to theory, and yes that includes faithfully observing the noise from empty ports.  This is more accurate than our generally accepted rule of thumb approach that an open port is silent by ignoring the observable noise.  

The contrived S-meter scale many of our favorite receivers from the past are amateur radio market engineered-marketing that everyone knew was "feel good" rather than factual.  

We exacerbate the S-meter scale nonsense by tradition, especially the everyone is "59" or "5NN" when contesting or in a hurry.

Is the FRS implementation lab grade perfection?  Will it toe up and hold the line with your professional grade station monitor?  Depends, though you can know it will be closer to lab grade than the approximations of legacy radios.

In prior discussions community members suggested implementing an alternative scale making SmartSDR report to them S-numbers they are happy with, rather than accurate.  FRS didn't take up the suggestion.  Truly what manufacturer would willingly "fake it" when they have the real goods because yesterday's market products were actually wrong?

So yes your Flex-6000 is going to tell you about the noise it actually hears, rather than ignoring that noise.  

On one of my older cars with a KM only speedometer is a KPH to MPH conversion chart - so you know that 55 MPH is 88 KPH and so on.  If your ham radio enjoyment depends on having a vintage pseudo-S-meter you could make yourself a similar chart.

73

Steve
K9ZW

Blog: http://k9zw.wordpress.com  

 
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Burt Fisher

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How much noise does it "actually hear" when a dummy load is attached right at the connector with no lead?
I get S4 reading with a resistor connected right at the coaxial connector.
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Joe Conover

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S3-4
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KY6LA - Howard, Elmer

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Which means that at the frequency you’re listening to Your radio is only capable of hearing only is -127 dMm plus 3x6dBm or -109dBm
(Edited)
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Joe Conover

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I have no problem with S meter showing true noise and stations transmitted signal strength
I’m starting understand my Ten Tec Omni 7 plus shows true noise in signal strength both my 6400M and Omni 7
Great on receive and transmit. I just don’t use Omni 7 after I got Flex 6400M it’s almost like 6400M put a Witches Spell on me lmao -it’s addictive like candy pop corn .
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W5UC

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Joe, if you haven't already, try turning the Preamp "RF gain" in the Ant tab to the "On" position. See if your noise floor doesn't drop.


73,
W5UC
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Joe Conover

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Yes it. Dropped all good thAnks