Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Wes Stewart]

I've done a little playing around with this.  I made some measurements, using my 
"old" K3, of the HAC1 voltage (applied to the FET i-f amp) vs. the RFG value 
just to see if I could see the "correction" Lyle spoke of.  It's a 
semi-interesting plot that I tried to post on the K3 Yahoo group. Unfortunately, 
I have a hard time describing Yahoo groups without resorting to swear words, and 
I couldn't accomplish the task. Someday, if I have the K3S out of the station 
line up, I'll repeat the measurements.


Wes

On 12/14/2017 8:57 PM, Al Lorona wrote:

You said, "In my opinion based on inspection of the schematic, the issue 
resides in the fet
post-filter amplifier that is controlled by the "hardware" AGC (and manual "RF"
gain control)."

You were making a relationship between hardware AGC and the loose spec of the 
FET in question. By saying that, I understood you to mean that the hardware AGC 
signal was being interpreted differently by the problem K3 compared to a 
'normal' K3 because of this FET. At least this is what it seemed like. I will 
accept that I misunderstood you and that I have no idea what you were trying to 
say.

Al  W6LX


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Re: [Elecraft] K3 / RF gain - S meter issue

[Bruce Meier]

Dale,

 

Thanks for the suggestion.   I ran the test on both K3s and they are exactly
the same.   The range is from 240 (fully clockwise) to 02 (fully
counterclockwise)   If I turn the RF gain slow enough I can see both rigs
incrementing or decrementing (depending on turning direction) 1 count at a
time.

 

/Bruce

 

 

From: Dale Boresz [mailto:dmbor...@gmail.com] 
Sent: Friday, December 15, 2017 10:12 AM
To: Bruce Meier
Cc: Elecraft
Subject: Re: [Elecraft] K3 / RF gain - S meter issue

 

Hello Bruce,

 

Just to rule out any electrical or mechanical discontinuities in the RF gain
control itself, you can use the CONFIG > SW TEST > SCN ADC option to examine
the ADC reading as a function of rotation position for both RF gain pots and
both AF gain pots. In order to be able to see the "SW TEST" option, you will
first have enable  "TECH MODE"  by setting  "CONFIG > TECH MD to 'ON'

 

Once you've selected SW TEST > SCN ADC, slowly rotate your rf gain control
from one extreme to the other while watching the 'steps' in the VFO B
display, looking for any sudden step changes. The values I observe run
contiguously from 002 at full CCW to 239 or 240 at full CW. 

 

Good luck with your troubleshooting.

 

73, 

 

Dale - WA8SRA

 

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Re: [Elecraft] K3 / RF gain - S meter issue

[Dale Boresz]

Hello Bruce,

Just to rule out any electrical or mechanical discontinuities in the RF
gain control itself, you can use the CONFIG > SW TEST > SCN ADC option to
examine the ADC reading as a function of rotation position for both RF gain
pots and both AF gain pots. In order to be able to see the "SW TEST"
option, you will first have enable  "TECH MODE"  by setting  "CONFIG > TECH
MD to 'ON'

Once you've selected SW TEST > SCN ADC, slowly rotate your rf gain control
from one extreme to the other while watching the 'steps' in the VFO B
display, looking for any sudden step changes. The values I observe run
contiguously from 002 at full CCW to 239 or 240 at full CW.

Good luck with your troubleshooting.

73,

Dale - WA8SRA


On Wed, Dec 13, 2017 at 4:25 PM, Bruce Meier  wrote:

> Looking for suggestions here from someone that might have experienced this
> same issue - -
>
>
>
> I have (2) K3 units (not the S model) that are acting different when the RF
> gain adjustments are turned fully counter clockwise.
>
> Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
> clockwise position the S-Meter registers full scale (60db over S9) as
> expected.
>
> Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
> clockwise position the S-Meter registers only S8.
>
>  Facts:
>
> Ø  With the exception of the S-Meter readings with RF gain settings, both
> units are working fine
>
> Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
> least both the same.
>
> Ø  Both units are running the same version of microcode (5.54) (2.88)
> (2.88)
> (1.26)
>
> Ø  Both units seem to register very close actual RF gain of stations when
> connected when tested on the same antenna
>
> Ø  Both units have the new synthesizers.
>
> Ø  Both units have second RX
>
> Ø  In both cases (both units) I can hear the audio level decreasing
> linearly
> as expected as the RF gain is turned counter clockwise
>
> I have tried to initialize the K3 and reload the firmware resulting in no
> change to the RF gain / S-Meter readings.
>
>
>
> Elecraft Tech Support suggested:
>
> Ø  Calibrating the s-meter – did nothing
>
> Ø  Next suggestion – send the rig to California.
>
>
>
> Anyone have this issue and fixed it??
>
>
>
> 73,
>
> Bruce N1LN
>
>
>
> __
>
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Al Lorona]

You said, "In my opinion based on inspection of the schematic, the issue 
resides in the fet 
post-filter amplifier that is controlled by the "hardware" AGC (and manual "RF" 
gain control)."

You were making a relationship between hardware AGC and the loose spec of the 
FET in question. By saying that, I understood you to mean that the hardware AGC 
signal was being interpreted differently by the problem K3 compared to a 
'normal' K3 because of this FET. At least this is what it seemed like. I will 
accept that I misunderstood you and that I have no idea what you were trying to 
say.

Al  W6LX
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Wes Stewart]

I don't think I said that.  I imagine the onset of hardware AGC is determined 
elsewhere.  What I am saying is that the dB/V gain change is non-linear and 
different from device to device.  I assumed, mistakenly it appears, that the 
bias voltage to the device was tailored via a lookup table to create a linear 
dB/V (if you can call dB linear) scale factor. Lyle's description, if I 
understand it correctly, says that they measure the gain control characteristic, 
but leave it be and correct the numbers via a table.


A much better choice here (IMHO of course) would have been something like an 
Analog Devices AD600 (See "A High-Performance AGC/IF Subsystem" by Bill Carver 
in QST, May 1996.)


Another place where the designers' QRP DNA got in the way of robust design was 
the choice of the second mixer.  The oft repeated claim that hardware AGC is 
protecting the DSP may be true, but the second mixer overload characteristics 
are even worse.


Wes  N7WS



On 12/14/2017 6:01 PM, Al Lorona wrote:

Wes stated that there's a component in the AGC circuit that changes the onset 
of hardware AGC due to component tolerances. I suggested putting that theory to 
the test by actually measuring it.

Al  W6LX


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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Bill Johnson]

Isn't that answered by Lyle's point #10?

73,
Bill
K9YEQ

-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Al Lorona
Sent: Thursday, December 14, 2017 7:02 PM
To: donw...@embarqmail.com; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

Wes stated that there's a component in the AGC circuit that changes the onset 
of hardware AGC due to component tolerances. I suggested putting that theory to 
the test by actually measuring it.

Al  W6LX
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Al Lorona]

Wes stated that there's a component in the AGC circuit that changes the onset 
of hardware AGC due to component tolerances. I suggested putting that theory to 
the test by actually measuring it.

Al  W6LX
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Lyle Johnson]

There are several things going on here.

1) The "hardware AGC" is derived at the 15 kHz IF and is designed to 
prevent overdrive to the DSP's IF Analog-to-Digital Converter (ADC).  It 
also serves to prevent the 15 kHz IF amplifier from being driven into 
non-linear operation.


2) The "hardware AGC" voltage is fed to the 8.215 MHz IF amplifier.  By 
placing the gain control here, it also helps to prevent overload of the 
2nd Mixer (8.215 MHz -> 15 kHz).


3) The "RF Gain" control voltage is fed to the same point at the 8.215 
MHz IF stage.


4) The RF ATTenuator (0 or 10 dB in the K3, more choices in the K3S) and 
PREamp (one choice in the K3, up to two choices in the K3S) are applied 
in the radio prior to the first mixer or crystal filter.  They thus have 
an impact on the "hardware" AGC."


All of the above is independent of the DSP subsystem.

5) The "RF Gan Cal" works by injecting known voltages to the 8.215 MHz 
IF amplifier control point and measuring the subsequent change in gain.  
The DSP measures this and creates a table.  Due to dynamic range 
limitations of the measuring system, the calibration procedure requires 
two signals levels to be injected. In the case of the higher level 
signal not being available, the factory default values are used.  Due to 
variations in the gain control led stage, there may be the change in S 
Meter indication that some of you have observed at high signal (or 
severely reduced RF Gain control) conditions.


In general, if you are going to do the RF Gain calibration, you really 
should use both signal levels.  The XG3 specifically provides the 
required levels.


6) The DSP regularly measures the control voltage to the 8.215 MHz IF 
amplifier. The RF Gain Cal information is used by the DSP when it then 
calculates the signal level in the IF passband.  It is not part of the 
signal control loop; it is strictly a measure and report function.


7) The DSP takes into account the PRE and ATT status provided by the MCU 
in the S Meter ABS mode; it ignores such information in the S Meter NOR 
mode.


8) The S Meter calculation is prior to the DSP's AGC algorithms so the S 
Meter is not affected by THR, SLP or other AGC-related settings.


9) The DSP presents the results of the S Meter calculation to the 
radio's MCU via a DAC voltage that is only routed to the MCU -- it has 
no other function in the radio.


10) The S Meter OFS and SCL values are used by the MCU (not the DSP) to 
manage the S Meter display of the DSP's DAC voltage on the K3's LCD.


Enjoy!

73,

Lyle KK7P
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Don Wilhelm]

Al,

My understanding of the hardware AGC is that it is fixed and is not 
dependent on the menu AGC parameters.  The AGC THR and SLP are strictly 
DSP parameters.


The Hardware AGC is there only to protect the ADC from overload due to 
strong signals.


There may some variation in the exact level that the Hardware AGC kicks 
in form K3 to K3 due to component tolerances.


The fact that the manual RF gain operates at the Hardware AGC point may 
be sufficient explanation that the RF Gain Control when at full 
counterclockwise position does not drive the S-meter to full scale 
(again due to component tolerances).


The real question in my mind is whether the K3 S-meter responds properly 
at its calibration points of S-9 and S-9+30.  And those points are 
correct with the RF Gain at full clockwise rotation.  Those calibration 
points are determined in the DSP section, and not in the hardware part 
of the K3.


73,
Don W3FPR

On 12/14/2017 6:40 PM, Al Lorona wrote:

This would be easy to test. Normally, 'hardware AGC' kicks in at an input 
signal level of -46 dBm or so. This point is essentially independent of the AGC 
THR and SLP settings. See if your K3 varies from this data point anomalously.

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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Al Lorona]

This would be easy to test. Normally, 'hardware AGC' kicks in at an input 
signal level of -46 dBm or so. This point is essentially independent of the AGC 
THR and SLP settings. See if your K3 varies from this data point anomalously.

Al  W6LX



__
In my opinion based on inspection of the schematic, the issue resides in the 
fet 
post-filter amplifier that is controlled by the "hardware" AGC (and manual "RF" 
gain control)  The specs on this device are very loose, IIRC, Gm can vary 2:1.  
Thus the response of this fet to AGC/RF gain varies from radio to radio 

Wes  N7WS
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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Wes Stewart]

Personally, I wouldn't go so far as to say the radio performs correctly. Without 
writing a long history, let's just say that I discovered this RF gain issue 8 or 
9 years ago.  I demonstrated it to an Elecraft engineer in my shack who had 
brought along his fully up to date K3 which we compared.  They were widely 
different.  Subsequently, I did a lot of beta testing of firmware that I believe 
spawned the RF gain calibration program.


In my opinion based on inspection of the schematic, the issue resides in the fet 
post-filter amplifier that is controlled by the "hardware" AGC (and manual "RF" 
gain control)  The specs on this device are very loose, IIRC, Gm can vary 2:1.  
Thus the response of this fet to AGC/RF gain varies from radio to radio, and as 
seen in another post, between the main RX and second RX in the same radio.  As I 
understand it, and I would love for someone at Elecraft to correct me if I'm 
wrong, the RF gain calibration program measures the radio gain control 
characteristics and generates a lookup table of correction factors to apply to 
linearize the control.


If I'm correct, I always been troubled by questions about the speed of this 
process.  Being an analog guy I understand resistor-diode networks used for 
similar purposes that operate essentially instantaneously.   The digital process 
not so much.


Wes  N7WS



On 12/14/2017 9:16 AM, Dan Atchison via Elecraft wrote:

I have a similar - but different! - issue on one of my Elecraft's.

I own both a K3 and a K3s.  Both are configured equally with the K3 having 
been upgraded to the highest level to achieve near K3s equivalency.


My K3s RF Gain control works exactly as expected, i.e. as the control is 
rotated counter-clockwise the "S-Meter" increases to a point at almost full 
scale.


On the K3, however, as the RF Gain control is rotated counter-clockwise and 
the "S-Meter" increases to about the "40-over" point at the control's 10 
o'clock position the "S-Meter" then inexplicably drops to the "S9" position 
where it remains for the remainder of the RF gain control counter-clockwise 
rotation. This shouldn't be but like N1LN's issue, the radio does otherwise 
perform correctly.  I have done everything that N1LN has done including the RF 
Gain calibration using a signal generator.


Very strange, indeed.

Dan -- N3ND

*

Date: Wed, 13 Dec 2017 16:25:20 -0500
From: "Bruce Meier"<beme...@bellsouth.net>
To:<elecraft@mailman.qth.net>
Subject: [Elecraft] K3 / RF gain - S meter issue


Looking for suggestions here from someone that might have experienced this
same issue - -



I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

?  Unit one ? s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

?  Unit two ? s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

 Facts:

?  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

?  Both units have ?almost? all mods installed.  If not all, they are at
least both the same.

?  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

?  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

?  Both units have the new synthesizers.

?  Both units have second RX

?  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.



Elecraft Tech Support suggested:

?  Calibrating the s-meter ? did nothing

?  Next suggestion ? send the rig to California.



Anyone have this issue and fixed it??



73,

Bruce N1LN



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[Elecraft] K3 / RF gain - S meter issue - Similar issue

[Dan Atchison via Elecraft]

More info.

Thanks to Brian, K3KO, some hints were given to check my particular 
issue.  Thanks also to Bob, K4TAX.


Since I have no intention of opening my radio (as the radio does work 
fine), I have discovered something of interest and a potential cause for 
the symptom I'm seeing.


As I apply a high signal level into the radio, I reach a point where the 
S-Meter behaves exactly like rotating the RF Gain control 
counter-clockwise (the reading drops).  This is easily duplicated.


Brian noted that perhaps what I am seeing is being caused by the K3 
Automatic Front-End Protection modification which my radio had its 
modification years ago.  The mod protection works as designed while 
injecting a high signal level into the K3, and I do see where the preamp 
(if engaged) is disabled.  Furthermore, I see HI SIG displayed in the K3 
VFO-B area.


Interestingly, my symptom happens at the same "signal level" the S-Meter 
reacts to with preamp disengagement, but without an injected signal just 
by rotating counter-clockwise the RF Gain control.  I do not, however, 
see the HI SIG level notification during this test and it matters not if 
the preamp is engaged or disengaged.  That said, the resultant S-Meter 
reading that had been "dropped" does follow both attenuation and preamp 
values.


Brian might be on to something!

Again, no intention of pursuing further unless Elecraft can duplicate 
and create a mod.


73 and thanks for the BW,
Dan



*********


 [Elecraft] K3 / RF gain - S meter issue - Similar issue

*Bob McGraw K4TAX* rmcgraw at blomand.net 
<mailto:elecraft%40mailman.qth.net?Subject=Re%3A%20%5BElecraft%5D%20K3%20/%20RF%20gain%20-%20S%20meter%20issue%20-%20Similar%20issue=%3Cf76213ce-61de-69fb-f4c5-3b0dc10f7db8%40blomand.net%3E>




My concern would be "does the S meter indicate correctly?"

Thus with 50 uV applied to the antenna input it should read S-9, and
with 0.78 uV applied it should read S-3, and with 5000 uV applied it
should read S-9 +40 dB.    I've checked my K3S at these and other values
and I'm confident that the S meter is accurate. Hence, I'm confident I
can give accurate signal reports.  Thus unlike many radios and their S
meters, they are only good for a rather unscientific and largely
inaccurate signal report, somewhat like a SWAG.

73

Bob, K4TAX


On 12/14/2017 10:16 AM, Dan Atchison via Elecraft wrote:
/I have a similar - but different! - issue on one of my Elecraft's. />//>/I own both a K3 and a K3s.  Both are configured equally with the K3 />/having been upgraded to the highest level to achieve near K3s />/equivalency. />//>/My K3s RF Gain control works exactly as expected, i.e. as the control />/is rotated counter-clockwise the "S-Meter" increases to a point at />/almost full scale. />//>/On the K3, however, as the RF Gain control is rotated />/counter-clockwise and the "S-Meter" increases to about the "40-over" />/point at the control's 10 o'clock position the "S-Meter" then />/inexplicably drops to the "S9" position where it remains for the />/remainder of the RF gain control counter-clockwise rotation. This />/shouldn't be but like N1LN's issue, the radio does otherwise perform />/correctly.  I have done everything that N1LN has done including the RF />/Gain calibration using a signal generator. />//>/Very strange, indeed. />//>/Dan -- N3ND />//>/* />//>/Date: Wed, 13 Dec 2017 16:25:20 -0500 />/From: "Bruce Meier"<http://mailman.qth.net/mailman/listinfo/elecraft>> />/To:<http://mailman.qth.net/mailman/listinfo/elecraft>> />/Subject: [Elecraft] K3 / RF gain - S meter issue />//>//>/Looking for suggestions here from someone that might have experienced />/this />/same issue - - />//>//>//>/I have (2) K3 units (not the S model) that are acting different when />/the RF />/gain adjustments are turned fully counter clockwise. />//>/?  Unit one ? s/n 1062: When the RF gain is decreased to full counter />/clockwise position the S-Meter registers full scale (60db over S9) as />/expected. />//>/?  Unit two ? s/n 1193:  When the RF gain is decreased to full counter />/clockwise position the S-Meter registers only S8. />//>/  Facts: />//>/?  With the exception of the S-Meter readings with RF gain settings, both />/units are working fine />//>/?  Both units have ?almost? all mods installed.  If not all, they are at />/least both the same. />//>/?  Both units are running the same version of microcode (5.54) (2.88) />/(2.88) />/(1.26) />//>/?  Both units seem to register very close actual RF gain of stations when />/connected when tested on the same antenna /&

Re: [Elecraft] K3 / RF gain - S meter issue

[Bruce Meier]

Thanks for the responses – here are the answers to the questions and
suggestions and a new piece of DATA associated with selecting the SUB-RX.

 

1.   I checked the S-Meter configs for both of my K3s – they are exactly
the same.

a.   SMTR OF  016

b.  SMTR SC  016

c.   SMTR PK OFF

d.  SMTR MD ABS

 

2.   I then ran RF Gain calibration using “Factory default RF Gain
Calibration data” as I don’t have the necessary test equipment

a.   Ran for both main and sub-RX

 

Ø  No change to the symptom on the suspect K3

 

3.   Just for the heck of it – I reloaded the currently installed
firmware using the K3 Utility 1.15.12.7

a.   MCU: 05.54

b.  DSP (both main/sub): 2.88

c.   FPF: 01.26

 

Ø  NO CHANGE

 

4.   I then downloaded the most recent firmware – only change MCU is now
05.60

 

Ø  No change

 

5.   I then selected the SUB RX – not sure why just did it.

a.   When I turn the RF gain counter clockwise the S-Meter increases to
60db over S9

b.  When I turn the Sub RX off – the S-Meter only increases to S7

 

NOTE:  I never tried this before, but it appears to be an interesting piece
of data.  Does this now point toward the Main RX in some way?

 

 

73,

Bruce – N1LN

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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Bob McGraw K4TAX]

My concern would be "does the S meter indicate correctly?"

Thus with 50 uV applied to the antenna input it should read S-9, and 
with 0.78 uV applied it should read S-3, and with 5000 uV applied it 
should read S-9 +40 dB.    I've checked my K3S at these and other values 
and I'm confident that the S meter is accurate. Hence, I'm confident I 
can give accurate signal reports.  Thus unlike many radios and their S 
meters, they are only good for a rather unscientific and largely 
inaccurate signal report, somewhat like a SWAG.


73

Bob, K4TAX


On 12/14/2017 10:16 AM, Dan Atchison via Elecraft wrote:

I have a similar - but different! - issue on one of my Elecraft's.

I own both a K3 and a K3s.  Both are configured equally with the K3 
having been upgraded to the highest level to achieve near K3s 
equivalency.


My K3s RF Gain control works exactly as expected, i.e. as the control 
is rotated counter-clockwise the "S-Meter" increases to a point at 
almost full scale.


On the K3, however, as the RF Gain control is rotated 
counter-clockwise and the "S-Meter" increases to about the "40-over" 
point at the control's 10 o'clock position the "S-Meter" then 
inexplicably drops to the "S9" position where it remains for the 
remainder of the RF gain control counter-clockwise rotation. This 
shouldn't be but like N1LN's issue, the radio does otherwise perform 
correctly.  I have done everything that N1LN has done including the RF 
Gain calibration using a signal generator.


Very strange, indeed.

Dan -- N3ND

*

Date: Wed, 13 Dec 2017 16:25:20 -0500
From: "Bruce Meier"<beme...@bellsouth.net>
To:<elecraft@mailman.qth.net>
Subject: [Elecraft] K3 / RF gain - S meter issue


Looking for suggestions here from someone that might have experienced 
this

same issue - -



I have (2) K3 units (not the S model) that are acting different when 
the RF

gain adjustments are turned fully counter clockwise.

?  Unit one ? s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

?  Unit two ? s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

 Facts:

?  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

?  Both units have ?almost? all mods installed.  If not all, they are at
least both the same.

?  Both units are running the same version of microcode (5.54) (2.88) 
(2.88)

(1.26)

?  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

?  Both units have the new synthesizers.

?  Both units have second RX

?  In both cases (both units) I can hear the audio level decreasing 
linearly

as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.



Elecraft Tech Support suggested:

?  Calibrating the s-meter ? did nothing

?  Next suggestion ? send the rig to California.



Anyone have this issue and fixed it??



73,

Bruce N1LN



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Re: [Elecraft] K3 / RF gain - S meter issue - Similar issue

[Dan Atchison via Elecraft]

I have a similar - but different! - issue on one of my Elecraft's.

I own both a K3 and a K3s.  Both are configured equally with the K3 
having been upgraded to the highest level to achieve near K3s equivalency.


My K3s RF Gain control works exactly as expected, i.e. as the control is 
rotated counter-clockwise the "S-Meter" increases to a point at almost 
full scale.


On the K3, however, as the RF Gain control is rotated counter-clockwise 
and the "S-Meter" increases to about the "40-over" point at the 
control's 10 o'clock position the "S-Meter" then inexplicably drops to 
the "S9" position where it remains for the remainder of the RF gain 
control counter-clockwise rotation.  This shouldn't be but like N1LN's 
issue, the radio does otherwise perform correctly.  I have done 
everything that N1LN has done including the RF Gain calibration using a 
signal generator.


Very strange, indeed.

Dan -- N3ND

*

Date: Wed, 13 Dec 2017 16:25:20 -0500
From: "Bruce Meier"<beme...@bellsouth.net>
To:<elecraft@mailman.qth.net>
Subject: [Elecraft] K3 / RF gain - S meter issue


Looking for suggestions here from someone that might have experienced this
same issue - -

 


I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

?  Unit one ? s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

?  Unit two ? s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

 Facts:

?  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

?  Both units have ?almost? all mods installed.  If not all, they are at
least both the same.

?  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

?  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

?  Both units have the new synthesizers.

?  Both units have second RX

?  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.

 


Elecraft Tech Support suggested:

?  Calibrating the s-meter ? did nothing

?  Next suggestion ? send the rig to California.

 


Anyone have this issue and fixed it??

 


73,

Bruce N1LN

 


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Re: [Elecraft] K3 / RF gain - S meter issue

[carlo bianconi]

Hi Bruce,

try to reload the factory data calibration before doing the calibration 
with a generator.


Usually it works.

73, Carlo

Carlo Bianconi Telecomunicazioni Official Elecraft Dealer Via O.Trebbi 8/B 
40127 Bologna - Italy Ph. 0515878825 mail carlobianc...@iol.it 
www.carlobianconi.com

Il 14/12/2017 14:38, Roger D Johnson ha scritto:
Is the S meter supposed to read 60 over 9 when the RF gain is turned 
all the way down?


Mine reads 30db!

73, Roger



On 12/13/2017 9:10 PM, Wes Stewart wrote:
I would first perform the RF Gain calibration using the K3 Utility. 
The calibration program measures gain characteristics and applies 
software correction.


Then run the S-meter calibration.

Wes  N7WS

On 12/13/2017 2:25 PM, Bruce Meier wrote:
Looking for suggestions here from someone that might have 
experienced this

same issue - -


I have (2) K3 units (not the S model) that are acting different when 
the RF

gain adjustments are turned fully counter clockwise.

Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

  Facts:

Ø  With the exception of the S-Meter readings with RF gain settings, 
both

units are working fine

Ø  Both units have ‘almost’ all mods installed.  If not all, they 
are at

least both the same.

Ø  Both units are running the same version of microcode (5.54) 
(2.88) (2.88)

(1.26)

Ø  Both units seem to register very close actual RF gain of stations 
when

connected when tested on the same antenna

Ø  Both units have the new synthesizers.

Ø  Both units have second RX

Ø  In both cases (both units) I can hear the audio level decreasing 
linearly

as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting 
in no

change to the RF gain / S-Meter readings.


Elecraft Tech Support suggested:

Ø  Calibrating the s-meter – did nothing

Ø  Next suggestion – send the rig to California.


Anyone have this issue and fixed it??


73,

Bruce N1LN


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Re: [Elecraft] K3 / RF gain - S meter issue

[Wes Stewart]

Both of mine do.

On 12/14/2017 6:38 AM, Roger D Johnson wrote:
Is the S meter supposed to read 60 over 9 when the RF gain is turned all the 
way down?


Mine reads 30db!

73, Roger



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Re: [Elecraft] K3 / RF gain - S meter issue

[Roger D Johnson]

Is the S meter supposed to read 60 over 9 when the RF gain is turned all the way 
down?


Mine reads 30db!

73, Roger



On 12/13/2017 9:10 PM, Wes Stewart wrote:
I would first perform the RF Gain calibration using the K3 Utility. The 
calibration program measures gain characteristics and applies software 
correction.


Then run the S-meter calibration.

Wes  N7WS

On 12/13/2017 2:25 PM, Bruce Meier wrote:

Looking for suggestions here from someone that might have experienced this
same issue - -


I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

  Facts:

Ø  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
least both the same.

Ø  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

Ø  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

Ø  Both units have the new synthesizers.

Ø  Both units have second RX

Ø  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.


Elecraft Tech Support suggested:

Ø  Calibrating the s-meter – did nothing

Ø  Next suggestion – send the rig to California.


Anyone have this issue and fixed it??


73,

Bruce N1LN


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Re: [Elecraft] K3 / RF gain - S meter issue

[Wes Stewart]

I would first perform the RF Gain calibration using the K3 Utility.  The 
calibration program measures gain characteristics and applies software correction.


Then run the S-meter calibration.

Wes  N7WS

On 12/13/2017 2:25 PM, Bruce Meier wrote:

Looking for suggestions here from someone that might have experienced this
same issue - -

  


I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

  Facts:

Ø  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
least both the same.

Ø  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

Ø  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

Ø  Both units have the new synthesizers.

Ø  Both units have second RX

Ø  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.

  


Elecraft Tech Support suggested:

Ø  Calibrating the s-meter – did nothing

Ø  Next suggestion – send the rig to California.

  


Anyone have this issue and fixed it??

  


73,

Bruce N1LN


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Re: [Elecraft] K3 / RF gain - S meter issue

[Nr4c]

Check Config:S-Meter Mode on both K3s. 

Sent from my iPhone
...nr4c. bill


> On Dec 13, 2017, at 6:11 PM, K9MA  wrote:
> 
> Are both units running exactly the same configuration, at least as far as S 
> meter and AGC parameters?
> 
> 73,
> Scott K9MA
> 
> 
>> On 12/13/2017 15:25, Bruce Meier wrote:
>> Looking for suggestions here from someone that might have experienced this
>> same issue - -
>> 
>>  
>> I have (2) K3 units (not the S model) that are acting different when the RF
>> gain adjustments are turned fully counter clockwise.
>> 
>> Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
>> clockwise position the S-Meter registers full scale (60db over S9) as
>> expected.
>> 
>> Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
>> clockwise position the S-Meter registers only S8.
>> 
>>  Facts:
>> 
>> Ø  With the exception of the S-Meter readings with RF gain settings, both
>> units are working fine
>> 
>> Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
>> least both the same.
>> 
>> Ø  Both units are running the same version of microcode (5.54) (2.88) (2.88)
>> (1.26)
>> 
>> Ø  Both units seem to register very close actual RF gain of stations when
>> connected when tested on the same antenna
>> 
>> Ø  Both units have the new synthesizers.
>> 
>> Ø  Both units have second RX
>> 
>> Ø  In both cases (both units) I can hear the audio level decreasing linearly
>> as expected as the RF gain is turned counter clockwise
>> 
>> I have tried to initialize the K3 and reload the firmware resulting in no
>> change to the RF gain / S-Meter readings.
>> 
>>  
>> Elecraft Tech Support suggested:
>> 
>> Ø  Calibrating the s-meter – did nothing
>> 
>> Ø  Next suggestion – send the rig to California.
>> 
>>  
>> Anyone have this issue and fixed it??
>> 
>>  
>> 73,
>> 
>> Bruce N1LN
>> 
>>  
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
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>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k...@sdellington.us
> 
> 
> -- 
> Scott  K9MA
> 
> k...@sdellington.us
> 
> __
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Re: [Elecraft] K3 / RF gain - S meter issue

[K9MA]

Are both units running exactly the same configuration, at least as far 
as S meter and AGC parameters?


73,
Scott K9MA


On 12/13/2017 15:25, Bruce Meier wrote:

Looking for suggestions here from someone that might have experienced this
same issue - -

  


I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

  Facts:

Ø  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
least both the same.

Ø  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

Ø  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

Ø  Both units have the new synthesizers.

Ø  Both units have second RX

Ø  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.

  


Elecraft Tech Support suggested:

Ø  Calibrating the s-meter – did nothing

Ø  Next suggestion – send the rig to California.

  


Anyone have this issue and fixed it??

  


73,

Bruce N1LN

  


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--
Scott  K9MA

k...@sdellington.us

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[Elecraft] K3 / RF gain - S meter issue

[Bruce Meier]

Looking for suggestions here from someone that might have experienced this
same issue - - 

 

I have (2) K3 units (not the S model) that are acting different when the RF
gain adjustments are turned fully counter clockwise.

Ø  Unit one – s/n 1062: When the RF gain is decreased to full counter
clockwise position the S-Meter registers full scale (60db over S9) as
expected.

Ø  Unit two – s/n 1193:  When the RF gain is decreased to full counter
clockwise position the S-Meter registers only S8.

 Facts: 

Ø  With the exception of the S-Meter readings with RF gain settings, both
units are working fine

Ø  Both units have ‘almost’ all mods installed.  If not all, they are at
least both the same.

Ø  Both units are running the same version of microcode (5.54) (2.88) (2.88)
(1.26)

Ø  Both units seem to register very close actual RF gain of stations when
connected when tested on the same antenna

Ø  Both units have the new synthesizers.

Ø  Both units have second RX

Ø  In both cases (both units) I can hear the audio level decreasing linearly
as expected as the RF gain is turned counter clockwise

I have tried to initialize the K3 and reload the firmware resulting in no
change to the RF gain / S-Meter readings.

 

Elecraft Tech Support suggested:

Ø  Calibrating the s-meter – did nothing

Ø  Next suggestion – send the rig to California.

 

Anyone have this issue and fixed it??

 

73,

Bruce N1LN

 

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[Elecraft] K3 - RF Gain / S-Meter

[Dick Dickinson]

Yes.did it last night and now the 'sweet spot' is gone.  

 

73,

Dick - KA5KKT

 

>Have you done the "RF" (really i-f) gain calibration?  If not, any
wackiness you 

>see is unsurprising. 

 

>Wes Stewart

 

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Re: [Elecraft] K3 - RF Gain / S-Meter

[Wes Stewart]

Have you done the "RF" (really i-f) gain calibration?  If not, any wackiness you 
see is unsurprising.


On 9/24/2016 12:16 PM, Dick Dickinson wrote:

I have an early, but updated K3.  I used to be one who thought the K3 was
often uncomfortable to listen to.  In the recent past while I have reset my
AGC values AND started cutting back the RF Gain.  For me this has made all
the difference in listenability.  However I find something curious with the
action of the K3 S-Meter relative to the RF Gain setting.

My daytime 40 meter background noise level runs S-6 and sometimes S-7 with
the RF Gain full clockwise.  That's per the K3 S-Meter which is calibrated
with the XG1 on 40 meters.  When I turn the RF Gain counterclockwise (down)
the S-Meter reading of background noise drops down to about S-4/5 when the
knob is at about 1:30.  This seems to be a sweet spot from a couple of
points of view.  Obviously background noise coming through the speaker is
less.  Signals above the noise level continue to come through fine.  Turning
the RF Gain further counterclockwise causes the S-Meter reading to rise as
expected.  The sweet spot seems to may vary a little by band / background
noise level.

This action of the S-Meter relative to the RF Gain is different from what I
have experienced with previous radios.  I can understand the S-Meter not
'rising' while the RF Gain is turned down...until the RF Gain action begins
to exceed the full CW reading, but I don't understand it lowering the
S-Meter level while moving CCW...to a point and then rising.  In my
experience with analog radios don't recall encountering a dip in S-Meter
reading when the RF Gain is turned down.

Perhaps this is common in the K3, but it is new to me.  I find it easy to
tune to a dead spot on the band and find the null in the S-Meter level.  I
do really enjoy listening now in this sweet spot area and it seems I'm
listening to 12dB or so less noise.

Is this common for the K3 and is it somehow different from other / analog
rigs?


Dick - KA5KKT

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Re: [Elecraft] K3 - RF Gain / S-Meter

[Ron D'Eau Claire]

Interesting Dick. I can't duplicate that on mine. Once I reduce the RF gain
manually to the point where the AGC is holding the gain the S-meter starts
to rise smoothly to max at min RF gain as expected. 

Perhaps there's some combination of the setting of the AGC slope or perhaps
if you have an AGC HOLD delay set you're seeing the noise level drop as you
reduce your RF Gain before the hold delay expires. 

Whatever it is, it sounds like time to save that configuration, if you've
not done so already, Hi! 

73, Ron AC7AC

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Dick
Dickinson
Sent: Saturday, September 24, 2016 12:16 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] K3 - RF Gain / S-Meter

I have an early, but updated K3.  I used to be one who thought the K3 was
often uncomfortable to listen to.  In the recent past while I have reset my
AGC values AND started cutting back the RF Gain.  For me this has made all
the difference in listenability.  However I find something curious with the
action of the K3 S-Meter relative to the RF Gain setting.

My daytime 40 meter background noise level runs S-6 and sometimes S-7 with
the RF Gain full clockwise.  That's per the K3 S-Meter which is calibrated
with the XG1 on 40 meters.  When I turn the RF Gain counterclockwise (down)
the S-Meter reading of background noise drops down to about S-4/5 when the
knob is at about 1:30.  This seems to be a sweet spot from a couple of
points of view.  Obviously background noise coming through the speaker is
less.  Signals above the noise level continue to come through fine.  Turning
the RF Gain further counterclockwise causes the S-Meter reading to rise as
expected.  The sweet spot seems to may vary a little by band / background
noise level.

This action of the S-Meter relative to the RF Gain is different from what I
have experienced with previous radios.  I can understand the S-Meter not
'rising' while the RF Gain is turned down...until the RF Gain action begins
to exceed the full CW reading, but I don't understand it lowering the
S-Meter level while moving CCW...to a point and then rising.  In my
experience with analog radios don't recall encountering a dip in S-Meter
reading when the RF Gain is turned down.  

Perhaps this is common in the K3, but it is new to me.  I find it easy to
tune to a dead spot on the band and find the null in the S-Meter level.  I
do really enjoy listening now in this sweet spot area and it seems I'm
listening to 12dB or so less noise.

Is this common for the K3 and is it somehow different from other / analog
rigs?


Dick - KA5KKT

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Re: [Elecraft] K3 - RF Gain / S-Meter

[KD7PY]

I brought this up way back in 2011

see: 
http://elecraft.365791.n2.nabble.com/RF-gain-sweet-spot-td6604787.html#a6607729

Ed   KD7PY  ex K7WIA



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View this message in context: 
http://elecraft.365791.n2.nabble.com/K3-RF-Gain-S-Meter-tp7622837p7622839.html
Sent from the Elecraft mailing list archive at Nabble.com.
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[Elecraft] K3 - RF Gain / S-Meter

[Dick Dickinson]

I have an early, but updated K3.  I used to be one who thought the K3 was
often uncomfortable to listen to.  In the recent past while I have reset my
AGC values AND started cutting back the RF Gain.  For me this has made all
the difference in listenability.  However I find something curious with the
action of the K3 S-Meter relative to the RF Gain setting.

My daytime 40 meter background noise level runs S-6 and sometimes S-7 with
the RF Gain full clockwise.  That's per the K3 S-Meter which is calibrated
with the XG1 on 40 meters.  When I turn the RF Gain counterclockwise (down)
the S-Meter reading of background noise drops down to about S-4/5 when the
knob is at about 1:30.  This seems to be a sweet spot from a couple of
points of view.  Obviously background noise coming through the speaker is
less.  Signals above the noise level continue to come through fine.  Turning
the RF Gain further counterclockwise causes the S-Meter reading to rise as
expected.  The sweet spot seems to may vary a little by band / background
noise level.

This action of the S-Meter relative to the RF Gain is different from what I
have experienced with previous radios.  I can understand the S-Meter not
'rising' while the RF Gain is turned down...until the RF Gain action begins
to exceed the full CW reading, but I don't understand it lowering the
S-Meter level while moving CCW...to a point and then rising.  In my
experience with analog radios don't recall encountering a dip in S-Meter
reading when the RF Gain is turned down.  

Perhaps this is common in the K3, but it is new to me.  I find it easy to
tune to a dead spot on the band and find the null in the S-Meter level.  I
do really enjoy listening now in this sweet spot area and it seems I'm
listening to 12dB or so less noise.

Is this common for the K3 and is it somehow different from other / analog
rigs?


Dick - KA5KKT

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