Give us a Choice with the S Meter

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  • Idea
  • Updated 11 months ago
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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!
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Rex K0KP

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Posted 1 year ago

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Bill -VA3WTB

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You are irritated from having a lab accurate signal meter? This is the high tech world of Flex radio and direct sampling. your asking for an inaccurate meter on the Flex?  I don't think
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Neal Pollack, N6YFM

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Cheers Bill.   My thoughts exactly.
The comedy here is that on, a fellow called Zenki goes ballistic all the time for lack of calibrated accurate S-meters on Yaesu, Icom, Kenwood, etc.
But HERE,  Rex wants the old un-calibrated relative style back!   (No offense Rex, but you will make Zenki's head explode :-)   [good entertainment indeed!] )

That said, as mentioned by K6OZY, with the API, there is no limit to the number of third party utilities that people can write and provide.     (In a perfect world, there is also little limit to features that FRS can build into SmartSDR and the firmware, but you do know that FRS does not employ thousands of programmers like IBM or HP?)   Hence, just like with DDutil and SliceMaster and FRstack, it makes perfect sense for some third party to build a general purpose metering application that would let you pick and display all types of metering options for the rig.


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I always thought my signal report to the other station was a function of how badly I needed their QSL card!
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KY6LA - Howard, Elmer

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You have legitimately posted your request fir a switch to convert the accurate Flex S-Meter into a more traditional innacurate Relative S-Meter similar to the approximations of signal strength derived from Legacy AGC Loops. Since Flex does not use Legacy AGC loops it might be hard to implement

I can understand that many people would gain comfort from the fiction of those readings WHERE no antenna attached implies S0 even though the Minimum Discernable signal is not -127dBm but rather something like -110dBm or S4.

Anyways I Always thought all DX and contest signal reports were 5/9 whatever. Hi. Hi.

While I personally applauded the demise of legacy S-Meters Let’s see how many likes you get.
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KY6LA - Howard, Elmer

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Continuing with the Legacy Fiction S—Meter.

If you receive a S9 or -73dBm signal and add 30dB gain in the preamp. A Legacy AGC loop will read S9+30dB. But your signal really is still -73dBm at the antenna and all the preamp should have done is reduced your noise floor by 30dB.

But again I can understand how people can prefer to enjoy the comfort of the fiction that a preamp makes a received signal at the antenna stronger because lowering the relative noise floor makes it seem so.
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Neal Pollack, N6YFM

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Hi Howard:

I am also a new Flex 6600 owner, and coming from the analog superhet world, I too was confused at first, actually until yesterday, about the different behavior on the Flex due to the different technology and measurement method.    I would propse that part of this problem, and maybe endless support calls and forum posts, is because FRS has not yet added a chapter to the user manual that is titled  "Coming to Direct Sampling SDR from the SuperHet Analog World?; What is different & What to Expect".    

Such a chapter would have shortened my learning curve by perhaps weeks, and saved a ton of forum posts.
For example, you can see this slow learning curve and confusion here;

Again, the radio works great and has really impressed me as a lab grade tool,
but what I was witnessing, using my previous radios as experience, was not what
I thought.  And without a chapter in the manual, I did not know if I had a problem,
or if it was simply a different design, method of measuring, or what.

So in summary;  It seems that threads like this, and feature requests like this, are
due to people using their previous analog radios as a frame of reference, and thinking
that new SDR radios need to feel/look the same way, else they may be broken.

The solution is having that extra chapter, whereby each and every buyer can easily see the educational material during the first few days of reading.


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KY6LA - Howard, Elmer

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Very Good suggestion
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KY6LA - Howard, Elmer

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Here is a link to the Woodbox Radio ANALOG S-Meter 

Looks and feels like one of the Legacy Meters but unfortunately unlike legacy meters it still gives you an accurate reading rather than an AGC Loop Approximation so 30dB Preamp gain does NOT increase the reading at the antenna

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James Whiteway

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I like it. Too bad the developer is not supporting it anymore. Well done graphics.
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Jay / NO5J

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I've got a 50 ohm BNC terminator screwed onto my XVTR connector.
I set a 500 Hz RX filter width.
And all I got was this crazy picture showing SmartSDR reading S-0.
No internal noise visible. No signals either.

Hard to argue with reality.

BTW when I switch it to read as dBm it reads as low as -135 dBm. There is always noise in this reality. It can be measured.

The level varies 2-3 dBm very slowly, but it won't read any lower than S-0.

When I turn off the 20 dB preamp it does read S-1 @ -120 dBm.

    #FlexRadio IRC chat

For real-time discussions


User created documentation.

         73, Jay - NO5J

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Neal Pollack, N6YFM

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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?

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James Del Principe

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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