How Accurate is the SmartSDR power Meter?

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  • Updated 4 years ago
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How accurate is this, anyway?  I don't own a decent wattmeter, but I have SmartSDR.  So, maybe I can get by without it.

Here's what I am trying:

I can capture the output of the "analog" power meter on Smart SDR window for my 6300.  I can also see that each "vertical line" or "vertical bar" on the display represents 1.48 watts.  The 1.48 value is deduced simply by counting the vertical bars to a given point (40, 100 watts) and doing elementary division (both agree).  I can also see how far the "red" lights up the display, too, when transmitting.

I've been fooling around with QRP just for the fun of it.  I know the value you set on the "RF Power" is not a precise number of watts, but reasonably close.

When I try "5" (that is, trying for 5 watts), I get red bars that appear to vary between 3 and 4.5 watts, depending on the band, based on simply observing (after a screen capture) how far to the right the red value goes.  I actually do this with "Tune" so I get a reasonably consistent value.

So, the question is, how accurate is it, really?  I'm pretty confident in terms of the basic math.  But, what I don't know is how large the error bars are.

Do I have a rough-and-ready wattmeter or not?
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Larry Loen WO7R

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Posted 4 years ago

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Cliff Batson

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I have to set the power on my 6300 to "7" in order to get 5 watts on my external wattmeter.  YMMV.

Cliff (N4CCB)
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Tim - W4TME, Customer Experience Manager

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It is going to vary by band and the SWR presented to the PA. but the meter is fairly accurate.  Not PowerMaster or Bird accurate, but close enough.
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Larry Loen WO7R

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Tim, this is what I'm looking for. The acid test for me would be whether I can fairly and honorably claim a QRP award without further ado.  The "measurements" from the display would have varied between 3 and 4.4 watts, depending on the band, doing straightforward extrapolations from the captured visuals.

I suppose I could borrow someone's meter, but if it was "close enough" that I know I was under 5, I'm already "good to go" as I have managed over 100.
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Reggie-k6xr

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My 6500 and SSDR indicates 80 watts on some bands and 85 watts on others. Using an inline wattmeter, the wattmeter indicates 100+ watts on all bands. I do not know why SSDR indicates so much lower
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Walt - KZ1F

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I believe both I and Al, nn4zz, have expressed the idea that FRS bag the faux meter face for a simple numeric, 11-16pt size for SWR, rf out, audio, incoming signal. It's easier to program, more accurate, less real estate on the monitor, and more informative.

Speaking of faux meters, I believe the ts-990 has what, from a distance, looks like a legacy meter. Very impressive graphics rendition. Some months back Steve was in a conversation with some others about making a graphical rendition of a real world object. What impressed me most was I didn't think that many people, esp their ages, ever took Latin.

While the Flex meters clearly aren't legacy analog meter graphics the appear to be 1st generation digital meters.


For myself and, I guess, Al, S 6, 98, 1.8:1 are way better and ya can't beat the size. This is what I did in XPSSDR. But then my graphic artwork leaves much to be desired. According to N1BED, my mailbox Icon looked like a "kid with a crayon" drew it. That was in the email companion to pmnos back in the 80's.

Just reflecting on a previous 'idea'.
(Edited)
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Al / NN4ZZ

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Hi Walt,
Actually Howard (among others) gets the credit for the numeric displays.  I just did the mockups.  My original idea was to improve the legibility by choosing a better color scheme and fewer bars.   (the current blue on black is not so good).    White on Black is much easier to read.  And the mockup provides some potential digital readout options for those that prefer numbers.  Here are some of the examples.




The power meter suggestions include altering the scales based on the power setting.  That probably wouldn't improve the accuracy but would make it easier to read.



More details here:

https://community.flexradio.com/flexradio/topics/idea_to_improve_the_swr_and_power_scale_readability



Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW......... V 1.5.1.70
SSDR / DAX...... V 1.5.1.152
CAT................... V 1.5.1.0
Win10
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Walt - KZ1F

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I thought I improved on it by bagging the graphics.. People may or may not agree.
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Larry Loen WO7R

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NN4ZZ, I like your suggestion, but why not go a step further and have them auto-scale?  It shouldn't be possible for anyone to get fooled because the meters have numbers on them.  We could even subtly change the font color on the numbers and/or the bars to make it just that bit more obvious.  Varying between 100, 10, and 1 as you suggest would do the job for all purposes.  Scale size would be picked based on whether the value was currently under 120, under 12, and under 1.2.  The only "hard" part would be to make it somewhat "sticky" so that if power was varying right on the threshhold it wouldn't keep flopping between scales.  It would stick with the larger scale until the power was below it with some consistency (like, say, for a half second or so).

Walt, KZ1F, there is still something to be said for your suggestion.  Maybe overlay the power level on the display, right on top of the graphics?
(Edited)
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KY6LA - Howard, Elmer

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You an find a DIGITAL FORWARD POWER METER AT


Flexmeter was written by w3xy. WWW.Denzone.com


d


It has readable colors (black on white) and gives you real numbers instead of barely visible meaningless lines.

Running it against external digital watt meters I found it slightly high but you can borrow a wattmeter to use as a calibration srandard and then use this one
(Edited)
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Walt - KZ1F

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Howard, look at it. That is a huge amount of screen real estate when all the human brain needs is a number.

Agreed, it looks pretty. Personally, I want the number. For pretty, I'll go to the gym.
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pa0bie

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The FLEXmeter does not see my FLEX.  What can I do wrong ?
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Walt - KZ1F

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In my prior comment I did not mean to imply getting a graphical program to look that good doesn't take a lot of time and skill. It does.
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KY6LA - Howard, Elmer

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Pa0bie. Suggest you contact the author W3 XY for assistance.
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pa0bie

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Thanks Howard.

I have just did that.

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KY6LA - Howard, Elmer

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If I recall correctly this is the one that reads the internal numbers in the 6000. It reads temp correctly now.

Size. I have 3 X 27" monitors. I only took a screen shot of it in the middle of SSDR to provide a demo of how it looks. IT IS ALSO RESIZABLE. I like black on white. Much easier to see than blue on black which are invisible to me.

I use it much more to set the AGC-T levels rather than by ear. If the average AGCis say -15 dBmFS on an empty part of the band.then I adjust the AGC-T to -18 dBmFS. Very easy and really useful

I am sure Flex could actually make the Power /SWR/S reading in SSDR useful by including a digital number somewhere in SSDR In the interim the Flexmeter is a good tool.
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Rick Hadley - W0FG

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Thanks for that link.  I just downloaded and installed it.  It does take up a lot of screen real estate, but it just happens to be exactly the size to fill in a space on my 3rd monitor that runs my CW Skimmer, HRD Rotator, DDUtil, & FRStack panels.  Makes for a really nice looking screen and it's nice to have all those parameters easily visible.
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DrTeeth

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Larry, the other issue with the current meter is that the scale gets more difficult to read where one would want the most readability (towards the left) IMHO. Currently useless for those that would like to try QRP, even if the accuracy were up to lab specs. I also get the impression that the readability took a turn for the worst recently. I cannot believe that somebody took a look at the current meter and thought that it looked okay in its current form.
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Peter K1PGV, Elmer

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Now, first: FWIW, I agree.  The power meter in SSDR is, ah, less than optimal. Let's say that to be nice.

But c'mon guys... we have software developers on here complaining that they don't have a display that they like.  I respectfully suggest it would quite literally take less time to code-up whatever you want to display than to write the post here complaining about what's being display currently by SSDR. A little DYI, boys... a little ham spirit!

That's what I did. It's like Burger King. A little code and you can "have it your way."

Peter
K1PGV
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Al / NN4ZZ

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Hi Walt,
Agree that since SSDR GUI is not something third parties can change, the only way to make it better within the GUI is for FRS to do it.  IMHO,  the add-ons are a good way to show what can be done but in the long run I'd prefer to see SSDR be as good as it can be and not have to run an extra program for something as basic as these meters.  

Just for reference, here are some stats on the idea for improving the SWR and Power meters
  • It has been on the idea list for 2 years
  • It currently has 28 votes
  • It is ranked #8 out of the 800+ ideas on the list so it's in the top 1% from the users perspective.
  • the status is "under consideration" and has been that way for a while.  (it would be nice to see it changed to "planned" )
GUI improvements are not show stoppers, so I'm not surprised this idea is still waiting to be addressed.  However it certainly keeps coming up and doesn't appear to be a complex change.  Maybe in the next year or so we will see it and some of the other GUI improvement ideas get done.  Here is a link to the idea in case anyone wants to add comments or votes. 

https://community.flexradio.com/flexradio/topics/idea_to_improve_the_swr_and_power_scale_readability
 
Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW......... V 1.5.1.70
SSDR / DAX...... V 1.5.1.152
CAT................... V 1.5.1.0
Win10
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DrTeeth

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Hi Al

>>GUI improvements are not show stoppers, so I'm not surprised this idea is still waiting to be addressed<<

I would rate them higher than that. As I said in an earler post, I cannot believe that somebody actually 'signed off' on some aspects of the UI

A rough edge here and a rough edge there has an additive effect and one wonders how things passed muster, especially as the bar is set so high with other aspects of SSDR. A UI that needs improving, over-sensitive sliders (that do not follow windows convention w.r.t. mouse wheel function), sliders that seem to get more difficult to control over time in that the 'active' area shrinks etc.

A drop of water dropping on ones head does not seem so bad, but after a while it does get under ones skin (https://en.wikipedia.org/wiki/Chinese_water_torture).

Some excellent graphic improvements have been posted here and it would be nice to see at least a few crumbs of UI enhancement thrown in the direction of those requesting them - yes power and SWR meters, I'm talking about you.
(Edited)
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Walt - KZ1F

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I think there are a couple of things going on here. First, I don't think the community is being real smart about the use of idea. I think, for instance, this topic has a lot of traction. Everybody should revisit that idea from 2 years ago or whenever and like it, assuming that's what most everyone decides they want (one voice). One can not like it twice so there is no cheating. If you already voted for it a second vote doesn't work...I tried. You know, how go a job did these folks do? Only one way to find out.

Then it needs to get brought to FRS attention. Oh, on the idea, I'd caution about being careful what you ask for. For instance the artwork you did Al, makes the same real estate even busier making the control that much harder to understand. As I referred to in my response to Peter, and I bet a real contester would acknowledge You don't want unnecessary head movement to know the state of the radio and transmission. Say, for instance, on the slice flag about 1/2 way down is the red slider for signal strength. if that was replaced with S6 or S1 just to the left of the frequency, that whole S meter control get go away, same info, more readable, less real estate. Yeah, ok, that is my idea which might not resonate with others but it's a thought I throw out. The meta message there is more infomation closer to the relevance of that information (proximity of reference) and less real estate. Same with the controls on the right
How much of that is required and how much is optional? So if we all (OK you all, whatever) have that discussion a deliberate vote, via like and let Steve/Gerald know that is what you want to see next...and don't shotgun it, pick one or two ideas and say you'd really like to see it next sprint.

Users should be realistic about what goes into a sprint. There is, in Agile, a release backlog. It is all the things Product decides they need or want. From that things get placed into any given Sprint backlog and rank ordered. Just because something is in the sprint backlog doesn't mean it makes it. So, if for any given sprint they only get one or two consensus ideas from the user community, they may actually show up.

Anyway, just my two cents. I think you ought to push for detachable panadapters. Three cents.
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Al / NN4ZZ

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Hi Walt,
We are getting a bit off topic, but here is the idea for detachable panadapters.

It has 56 votes and is actually the number 1 most wanted idea of the 800+ ideas.  It was submitted about 1 year ago.  

https://community.flexradio.com/flexradio/topics/enhancement_to_let_you_drag_a_panadapter_to_another...

FWIW, I think this one will be a much bigger deal to implement.   At least from my experience with a team that tackled the same type of re-factoring on a similarly complex application, it was more than we expected.

IMHO, many of the other GUI improvement ideas are much simpler to implement and could be delivered in a lot less time than this one.  So I do understand the evaluation FRS has to consider on any of these "buff and polish" type improvements.   And they also have to consider how they compare to the big ticket items like noise mitigation, WAN remote, SO2R integration, Maestro, etc.

Hopefully we will see some of them delivered eventually.  And maybe some will come along in the remaining 1.X and new V 2.X releases.   With the demise of the detailed road maps, we just have to wait and see what comes. 

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW......... V 1.5.1.70
SSDR / DAX...... V 1.5.1.152
CAT................... V 1.5.1.0
Win10
 
  
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Walt - KZ1F

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My experience is different. I'll let it go at that.