[Elecraft] KX2 added to Sherwood's list

[Igor Sokolov]

The problem described below also exists in KX3,

That is why I always  adjust bandwidth to 50,150,250, 350 etc Hz.


73, Igor UA9CDC


01.08.2017 16:25, John Reilly пишет:
>
> Here are the odd details on the KX2 filter leakage.  If the filter 
> bandwidth is 500, 400, 300, 200 or 100 Hz, filter leakage makes the 
> measurement at 2 kHz impossible.  On the other hand, if the filter 
> bandwidth is 550, 450, 350, 250, 150 or 50 Hz, then the measurement 
> can be made.  The League chose to publish a 2-kHz dynamic range in QST 
> even though the measurement cannot be made on the high side with the 
> standardized 500-Hz filter bandwidth (or any even bandwidth value). 
> Note:  Both the League and I only publish the LOWER of the two 
> measurements.  Let’s say the low side dynamic range of some radio is 
> 95 dB and the high side is 90 dB. Both the League and I publish the 
> lower worse-case 90 dB number. In the case of the KX2, I couldn’t pick 
> the lower of the two readings since no measurement is possible when 
> using the standard 500-Hz filter.
>
> Since the 2-kHz dynamic range value could not be made with the 
> standard filter bandwidth at 2 kHz, but could be made at a 3-kHz 
> signal spacing, I published that data.  It may be of interest that the 
> 2-kHz dynamic range number with the non-standard 450-Hz bandwidth was 
> only 1 dB worse than the 3-kHz value.  The point of listing the 3-kHz 
> value, or any other radio with a non-2 kHz listing is to point out the 
> radio has a limitation in its filter performance.
>
> My long form report on the KX2, available in PDF format, goes into 
> detail about this issue, and has data on the two radios I tested, 
> listed by serial number.
>
> At this point, Elecraft does not know why the KX2 behaves this way, or 
> whether there is a possible firmware fix.
>
> Rob Sherwood
> NC0B
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