[Elecraft] P3 lvl cal?

[Alan Bloom]

Hi Matt,

If they matched it would be a coincidence.  For example, if the P3 is 
set to 45 kHz span, then each frequency point on the P3 display is about 
100 Hz wide.  If the K3 bandwidth is 2.7 kHz, then on a wideband signal 
like band noise or SSB, 27 times (14 dB) as much signal is getting to 
the K3's S meter as gets to each frequency point of the P3.  So you'd 
expect the average signal level on the P3 to be about 14 dB (2 or 3 
S-units) lower.

To illustrate this without a P3, try this:  Set the K3 to the normal 2.7 
kHz bandwidth, tune in an SSB signal and note the S meter reading.  Now 
change the K3 bandwidth to 100 Hz and note the S meter reading.  It will 
be much lower.

Alan N1AL


On 4/14/2013 4:37 PM, Matt Zilmer wrote:
> Hi Alan,
>
> I would guess that running Peak on the P3 and having the S meter on
> the K3 set to PEAK ON should give roughly the same results.  Correct?
> Or does the same discrepancy you advised below exist?  Peak and PEAK
> ON similarity is what I'm seeing here on the K3 / P3.
>
> 73,
> matt W6NIA
>
> On Sun, 14 Apr 2013 16:19:17 -0700, you wrote:
>
>> Tom,
>>
>> There are several reasons why the signal level can be different on the
>> P3 and K3, as explained in the "How to Set Up and Interpret the P3
>> Display" section of the P3 Owner's Manual.  The main reason is that the
>> effective bandwidth of the P3 is narrower than the K3, so more of the
>> signal gets through to the K3 S meter than a single pixel on the P3
>> display.  For that reason, the signal or noise level on the P3 can
>> appear quite a bit lower than on the K3 S meter.
>>
>> Alan N1AL
>>
>>
>> On 4/14/2013 3:46 PM, cx7tt at 4email.net wrote:
>>> Hello All,
>>>
>>> Question about the Lvl cal operation of the P3. I have noticed a 2 S
>>> unit diff between the K3 and P3.  I used the XG-1 to make sure the K3
>>> was set properly. Using Lvl cal, I noted the default was -5.4 and my  P3
>>> was -9.6.  To get a K3 S meter reading of S4 to equal S4 on the P3, I
>>> had to increase the Transfer gain to -30.0!
>>>
>>> This seems excessive. Would appreciate some guidance on how to resolve
>>> this issue.
>>>
>>> 73
>>> Tom
>>> CX7TT
>>>
>>>
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