[Elecraft] [K3] K3 S Meter

[Don Wilhelm]

Correction - Lyle's post was November 5.
73,
Don W3FPR

Don Wilhelm wrote:
> Bill,
>
> If the K3 S-meter is calibrated with the  preamp ON, and then ABS mode 
> is set on, the S-meter response for a 50 uV input will be S-7.
> If one is going to use S-meter ABS, then it is best to calibrate the 
> S-meter  for S-9with the preamp off.
>
> Yes, I know what "the manufacturer's instructions" say, but I know how 
> my K3 responds, and I also recall Lyle Johnson's response to this exact 
> situation in his posting of November 15, 2009 in which he said the 
> S-meter must be calibrated for the way you will use it.  He in fact 
> calibrates his with the PREAMP and ATTN both OFF and uses the S-meter in 
> ABS mode (just as I do).  When calibrated that way, it will not be 
> correct in NORMAL mode if the preamp is ON.
>
> In other words, the S-meter will respond correctly only under the 
> conditions for which you calibrated it.  You get to decide what your 
> normal operating situation will be - S-meter normal or absolute, preamp 
> on or off and attenuator on or off.  I prefer to use S-meter absolute so 
> S-9 indicates 50 uV at the antenna input regardless of whether the 
> preamp or attenuator is on or off.  Take your pick.
>
> Yes, I believe the manual could be more explicit.
> 73,
> Don W3FPR
>
> Bill W4ZV wrote:
>   
>> On Wed, Nov 18, 2009 at 12:09 AM, Philippe Trottet [via Elecraft] <
>> ml-node+4023431-500668120 at n2.nabble.com<ml-node%2B4023431-500668120 at n2.nabble.com>
>>   
>>     
>>> wrote:
>>>     
>>>       
>>   
>>     
>>> Dears
>>> I've seen on the manual S9 /50 microvolts is adjusted with Preamp ON .
>>> As a new Elecrafter I need some explanations, because with my previous
>>> rigs, I use to calibrate S9 without the preamp.
>>> Thanks
>>> Philippe A65BI
>>> K3 #3616
>>>
>>>     
>>>       
>> Bon jour Phillipe,
>>
>> The simple answer is "Always follow the manufacturer's directions".  A more
>> complex one is that the K3, being a DSP rig, compensates internally in
>> firmware for the fact that PREamp is ON during the calibration procedure.
>>
>> I also recommend using CONFIG: SMTR MD - ABS.  This will place the K3's
>> S-meter in ABSolute mode, so that the S-meter always reads the signal being
>> applied to the input terminals correctly, independently of whether PRE or
>> ATT are selected internally.  This is also different than most rigs but, if
>> you think about it, it is better since the S-meter always read the true
>> signal level at the input terminal, before any gain or attenuation is
>> applied inside.
>>
>> 73,  Bill  W4ZV
>>
>>   
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>>     
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