[Elecraft] K3 dbV in 2.38

[Jack Smith]

I've independently measured the linear range of the DBV function as just 
over 60 dB, which is quite impressive. You can see the plot at
http://www.cliftonlaboratories.com/elecraft_k3_noise_blanker_and_crystal_dsp_filtering.htm.

That page also provides measured filter response curves using the K3's 
DBV function.

DBV is a very useful tool and a tip of the hat to the lads at Elecraft 
for including it. (lasses as well as lads, if appropriate.)

Jack K8ZOA
www.cliftonlaboratories.com



Eric Swartz WA6HHQ - Elecraft wrote:
> Hi Brian,
>
> The dBV and AFV functions were designed primarily for use with steady 
> state lab signals to test receiver sensitivity etc. We added these two 
> displays to speed our final test of the K3 in production, and as an 
> aid to do this in the field with simple tools like our XG2 test 
> oscillator. They were not intended for dynamic signal, off the air 
> measurements.
>
> 73, Eric  WA6HHQ
> ---
>
> _..._
>
>
>
> alsopb wrote:
>> Apparently I need some help in trying to use this dBV capability with 
>> on the
>> air signals.
>>
>> For example, using it as an AGC off "relative" S-meter with digital 
>> readout
>> to run some antenna pattern checks for skewness etc.
>>
>> I've used it just fine in "lab type" measurements with a constant signal
>> source.
>>
>> First question.  What is meant by stable value of AFV?
>>
>> Here's what I see for a bunch of AFV edited values one after another 
>> with no
>> change in K3 settings.
>> 1579,1688,1598,1624,1696,1613, 2168,1758,1425.
>> The range is 6db. 
>> Is the reference value of AFV used in the dbV calculation the last 
>> one taken
>> at the instant one leaves the menu entry?  Yes, it doesn't really 
>> matter if
>> that values is used forever.
>>
>> Suppose one then takes a series of dbV measurements,  is the 
>> reference AFV
>> ever changed during the set of readings?
>>
>> The integration times available are 500 and 1000 ms.  It would seem that
>> longer integration times are required for off air type measurements.
>>
>> Is there any integration time in the measured voltage used in the dBV
>> calculation?  Or is it nearly an instantaneous value?  For off the 
>> air type
>> measurements, it would seem that a suitably long value is needed.
>>
>> 73 de Brian/K3KO
>>   
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