S Meter Reading after Service

Burt Fisher

Why would anyone not be friends over a disagreement about which rig is better? I could see it if you insulted them personally but if someone said my rig was a piece of ****, so what. If they said I was an a-hole for selecting a Flex different story.

KY6LA_Howard

@Joseph.  What do you not understand about

1.  The FrozenThermometer Paradox

2.   S0=-127dBm

yes you were teaching the incorrect information about S meters to your students

but heck lots of stuff I taught students has later been revised new knowledge. .  

[Deleted User]

Then they were not really friends

Mike-VA3MW

Another way to put it.  The 'other' radios can't read low enough into the noise floor.  They are not calibrated.

James Whiteway

Bert, each example he gives with the Flex differs because different slice bandwidths he has set on each band as well as modes. He starts with SAM at its widest setting. So, it's not a balanced comparison. James WD5GWY

Joseph Rodick

Burt;  Last year I lost a friend of over 40 years do to him having an Elecraft K3.   With his insistence, we compared rigs, side by side.  It quickly came apparent that the flex was the rig of choice and he just could not deal with it.   My other friend had an Icom 7610.  So after viewing your Youtube link, YES, I would choose Flex over Elecraft in a heartbeat.  I could go into reason after reason why the Flex side by side was the rig of choice, but this forum is not for that and I would never want to dismay a fellow ham on their rig.  The S meter reading is something I am truly trying to understand.  Thank you for your input and God Bless.

Michael N3LI

Hi Joe. It's just an improvement that takes a bit of getting used to. When I first fired up my 6300, I was also struck by what seemed like a whacky S-Meter.

But after a few questions and some digging into how this radio works, I figured it was a much more sound way to do this signal level thing.

You're going to love this radio. Right now I'm listening to some CW where I'm hearing an Op that is down in the noise around -120 dbm. All the more impressive considering I'm about 3/4 of the way toward profound deafness. 

Don't let the axe grinders wear ya down Joe. Every time someone posts a perfectly norma question about the S-meter and SWR, they come out  to  confuse the issue.


Re the radio comparisons - our club has a 7610 and a K3S. Neither of them compare favorably to my 6600.

The only place where they are better is the Flex radios have issues with Windows 10. But then what doesn't? A forced Windows update and reboot just took my APRS station and iGate down. I'd take it off the internet, but that kinda defeats the purpose of an iGate.

Joseph Rodick

Thank you for your post,   Like I previously posted, I lost two long term friends just because of my 6400M.  In both cases, I did not want to do a side by side only because I feared what would and did happen.  I am slowly learning from past posts and do have a better understanding now on how Flex measures S/DB.  I thank the community for their input.  It has been a learning experience.  Maybe just maybe, you can teach an old dog. lol. God Bless

Mike-VA3MW

Joseph

Wow, we are sorry to hear that about your friends, especially in a hobby such as this.  I guess it is the same as arguing over Trucks or Cars or... anything.    Good friends are a hard find.  

The S Meter discussion is a very good one and some people provided some very positive perspectives and even I learned a few new tricks.

73

Joseph Rodick

Michael;  Thank you for your post, however, I lost a long term friend just because his Elecraft K3 did not come close to measuring up to my 6400M.  After reading all the posts and doing a little research on my own, I have determined that Flex is correct.  Sometimes passion gets the better of us.  I saw first hand how passion can hurt and ruin a relationship.   I personally did not think his K3 was bad, but in a number of areas, side by side, my 6400M won and his passion then anger got the better of him.    There are a lot of good radio's out there, and everyday hams make a decision based on past experience, features, and budget.  I remember when I thought my HW101 was the best of the best.  Bottom line, I posted my comment based on my past experience and knowledge and I have learned that I was wrong in a number of areas.  Learning is good.  God Bless

Lawrence Gray

Funny thing--when I used a calibrated signal generator with output -76 dB, my 6500 read S8.5,  With the output at -109 dB, it read S3--seems to work fine?

Larry, W1IZZ

Mike-VA3MW

So.. in the world of all of us trying to be nice, I have removed a few posts that didn't really contribute and I was worried about how it would go.  

If you have a concern, you can reach out to me personally.  

73

Alan

Joseph, you wrote, "I used to teach electronics, and in the past, I taught my students to short out the input to zero out the meter or scope"

Yes, but the device being "shorted" had/has internal resistance/impedance (R/Z).  When you shorted the terminals, you created an internal series current flow path through the device, through the internal R/Z, through the shorted terminals, back to the device.  There was a un-measurable voltage drop across the series internal R/Z.

Much of the S-meter discussion is above my knowledge level, but perhaps the internal resistance/impendence is an analogy to what the others are saying about how Flex measures S level.   In your shorted terminal example above, you cannot measure the voltage drop across the internal (Rs) of the device, but you know it is there.  You could measure the voltage drop across the shorted terminals (VL =0V).  Measuring 0V at the terminals does not measure the voltage source (Vs) because it leaves out the voltage drop of the internal R/Z  (Rs).



Alan

Alan

BTW, This is the circuit used to derive the maximum power transfer between two circuits.  Calculus is used to take the second derivative of the current as a function of RL when maximizing Power (P=I*2R).

Same as the idea of matching the antenna Z to the Rig Z for maximum power transfer.

Alan

Lawrence Gray

Fine Job--needs to be done more often.  Negative comments such as calling people trolls or other pejoratives, have no place here and serve no purpose.

Each person is just trying to learn and some folks are more technical than others.  This was an interesting, if a little repetitive, discussion, providing good information to folks who may not understand the overall concepts discussed.

Mike VE3CKO

Trolls need to be called out for what they are. They add no value, they repeat and repeat and jump at opportunities to create division. A more politically correct phrase would be "Negative Nancies" but please continue to call them what they are. If it hurts their feelings, they can leave and troll some place else.

John KB4DU

OK So I'll go first.

Freq           0              +32   

14.140    -113dBm    138dBm

7.190    -112dBm    -132dBm    -125dBm on RXA (open)

3.900    -114dBm    -130dBm    -125dBm on RXA (Open)

Readings all taken with a 50 Ohm load on ANT1, preamp zero (no Att) and preamp +32.  I compared readings on RXA (Open), and they were the same on 20M, but different (more noise) on 40 and 80. Don't know why.

Pretty close to the charted expectations. I am in a high noise environment (next to an Army post), so not really ideal for precise testing.

Brian Denley KB1VBF

Mode and bandwidth?

Brian Denley KB1VBF

Mode and bandwidth?

Pat N6PAT

It's very sad that so many threads end up this way. I've emailed both Gerald and Dan in the past about the rude behavior and name calling that happens in this forum.

A big help would be the addition of an ignore button. I'm surprised there isn't one.

John KB4DU

cw and 500 Hz as on the previous post.

Brian Denley KB1VBF

The Japanese radio smoke little effort for accuracy.  

Brian Denley KB1VBF

**** didn’t see that until late.  I will take my reading tomorrow.

Brian KB1VBF

Joseph Rodick

I was sickened over the loss.   I knew the passion both had for their radio's and really did not want to make a side by side comparison do to past antenna and radio decisions.    I only brought it up do to one of the posts mentioning and promoting Elecraft.   I have always felt that my opinion and thoughts are subject to change without notice.  I have learned a lot from this post and feel it has been a benefit to most dealing with the S meter readings.  I thank you for removing some of the negative posts.   I question Michael,  when you personally give a signal report, do you give the straight S meter reading or do you subtract the noise?  

Joseph Rodick

Alan, Thank you for your input, great post, God Bless.

Lawrence Gray

For what it might be worth:

6500 running v3.1.7, 50 ohm dummy load on ANT1--all others open, DSP functions off, Preamp 0 :

Band   Mode  BW          Signal
20 M   USB    2.1 kHz    -114 dBm
20 M   CW      100 Hz    -129 dBm
40 M   LSB     2.1 kHz   -114 dBm
40 M   CW      100 Hz    -129 dBm
80 M   LSB     2.1 kHz    -114 dBm
80 M   CW      100 Hz    -129 dBm

The readings bounce around +- 1 dBm,

Larry, W1IZZ

Michael N3LI

Looks like that is working pretty much correctly. There is a proper way to measure the noise floor on a Flex, and there it is. Go as narrow as you can. The only inaccuracies I've had are eyeballing where the peaks of the static are. Some SDR software has peak measuring. But I certainly wouldn't want it on a request list for SSDR

Michael N3LI

Too many Michaels in this thread! Anyhow, when I give out a signal report, I simply eyeball the S meter and give whatever shows up on the right side. I also hand out the dbm, and give a sound quality report. Which I find that having a Flex, I get a lot of requests for quality reports.

Except when contesting, and then everyone gets a 5 of 9 or 5nn.

Then I ask them to repeat everything...... 8^)

Lawrence Gray

Yes, I'm aware of the measurement technique.  I used 100 and 2.1 for illustration of the effect of bandwidth on the noise measurement.  Sherwood uses a CW bandwidth of 500 for his published noise floor measurements.  At a CW BW of 500, my 6500 reads -121 dBm (20M with conditions as as above), which is 3 dBm lower than Sherwood measures.  Seems reasonable, since we are checking the radio with itself and the "meter" is averaging the noise in some manner.

Too bad the source code for the Woodbox S meter+ is not available.  Probably could add a feature to display legacy "S" meter readings for anyone who wanted it.

Anyway, it is always fun to have an excuse to deep dive into an issue.  A great discussion, other than the elementary school name calling stuff.

Burt Fisher

Most here are way more talented than I, I am not like the guy with the sword. I am the one with a gun, no match for the talent here. But I represent Joe Ham, who wants an S-0 when there is no signal. The attitude shown by some here of superiority could make Flex a niche player.
https://www.youtube.com/watch?v=kQKrmDLvijo