[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"<bemeier at bellsouth.net>
> To:<elecraft at 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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