Re: K4 Dynamic Range

Rob Sherwood
 

Since the ADC in the K4 is the same as everyone else (quote Wayne), excluding Flex (my comment), I would expect the dynamic range to be about 100 dB, maybe a few dB less, with similar sample variation as observed in the Icom radios.  The K3 is about 105 dB.  Who would ever notice that difference? 

 

On the other hand, a K3S blocks around 150 dB above the noise floor, while the Icom and Flex over-range the ADC in the mid 120s.  (The term blocking does not apply to a direct sampling radio.) 

 

The only time I have ever seen an Icom over-range was a 7300 on 10 meters with preamp 2 enabled, and a trucker drove by on 11 meters 700 feet from my 5-element mono-band Yagi which was pointed towards the highway.  There is a slight (?) possibility the trucker was running more than 5 watts!

 

Note: I live in the country in Colorado, not on the east coast or in EU on 40 meters with big BC signals above 7200 kHz.

 

Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Drew Vonada-Smith K3PA
Sent: Friday, May 17, 2019 9:57 AM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K4 Dynamic Range

 

Of course, the radio looks great with the minimal information currently known.  One thing that gives me pause is the option to add a superhet RX for the highest dynamic range.  If this was felt to be a useful option, the question is, what is the dynamic range for the direct sample mode?  And how much better is it with the superhet RX option?

Direct sampling is technically interesting and offers advantages, but if the dynamic range is not at least as good as the K3 in this mode, I'm not interested.  Note: I use SO2R, so this strict a view will not be as important to many.

If (I say if because we don't know) what Elecraft has done is create a direct sampling radio to compete with "gee whiz!" market perception of Icom/Flex while having an essentially separate RX option to keep the radio high on the Sherwood charts, then they may have done us and themselves a disservice in trying to be all things to all people.

73,

Drew K3PA

 


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