http://elecraft.85.s1.nabble.com/Elecraft-K4-now-in-Rob-Sherwood-s-RX-performance-table-tp7669789p7669795.html
The two other responses do somewhat beg the question about what happens to the K3s used market and pricing. Not a lot of K3s for sale unlike the trickle to flood of k3.
At one point, I thought people were hanging on to their K3s waiting for a K4 upgrade which might well still be valid but I also wonder if people will simply stay with the K3s as the performance is clearly great and forgo the flexibility an SDR rig brings.
> On May 28, 2021, at 10:32 AM, Henry Pollock - K4TMC <
[hidden email]> wrote:
>
> I Love my K3+(new syn)!
>
> 73,
> Henry - K4TMC
> (K3 #98)
>
>> On Fri, May 28, 2021 at 1:22 PM BRUCE WW8II <
[hidden email]> wrote:
>>
>> I LOVE my K3s
>>
>> Bruce
>> WW8II
>>
>>> On Fri, May 28, 2021 at 12:31 PM Wayne Burdick <
[hidden email]> wrote:
>>>
>>> Sherwood has posted his measurements of the K4D's receiver performance in
>>> his table:
>>>
>>>
http://www.sherweng.com/table.html>>>
>>> We're quite pleased with his test results, which confirm that the K4/K4D
>>> is near the top of its class (direct-sampling SDRs). A K4HD would provide
>>> somewhat higher dynamic range for those stations in extreme signal
>>> environments, but the vast majority of operators will find that the
>> K4/K4D
>>> more than meets their needs.
>>>
>>> I'd like to highlight a few important items in Rob's chart.
>>>
>>> First, the K4D has a high 2 and 20 kHz dynamic range value of 101 dB.
>>> Because it's a direct-sampling radio, this figure will hold at nearly all
>>> offsets from strong signals. Second is the block dynamic range number
>> (128
>>> dB), higher than almost every other "pure" SDR measured. Finally, there's
>>> the LO noise (local oscillator; 148 to 155 dB) -- again, very favorable
>>> compared to all competing SDRs. This is an important number correlated
>> with
>>> reciprocal mixing dynamic range (RMDR).
>>>
>>> Taken together these demonstrate that the K4D will offer excellent
>>> performance in crowded band conditions.
>>>
>>> Inevitably a question will arise regarding the chart position of the K4D
>>> relative to a couple of our other transceivers: the K3S and KX3. There's
>> a
>>> bit of "apples to oranges" in both comparisons.
>>>
>>> The K3S uses a superhet receiver architecture. The K4HD will provide a
>>> receive setting that emulates this superhet performance when and if it's
>>> needed. But the "pure" (direct sampling) method used by the K4 (all
>> models)
>>> has many advantages. One is the elimination of artifacts associated with
>>> crystal filters. Another is that, as a pure SDR, the K4 has a far more
>>> flexible architecture. We'll be able to provide updates to the receive
>> and
>>> transmit digital signal chains that cannot be added to a superhet like
>> the
>>> K3S or its competitors.
>>>
>>> The KX3 is another Elecraft radio high on Sherwood's chart. Its
>>> performance is excellent, especially at its price point. But its numbers
>>> relative to the K4 are somewhat misleading, as hinted at by Rob's
>>> footnotes. The KX3 uses a quadrature downsampling architecture, which
>>> digitally samples at baseband audio rather than at RF. This is ideal for
>> a
>>> radio like the KX3 that has to have very low current drain for portable
>>> operations. The K4 uses a direct-samping architecture that requires a
>>> higher power digital signal chain, resulting in important benefits over
>>> quadrature downsampling including much higher and more consistent
>> opposite
>>> sideband image suppression and 2nd-order intermod rejection. So the two
>> are
>>> really designed for different applications.
>>>
>>> Overall, this first independent test of the K4 validates the performance
>>> of our SDR architecture. Feel free to send us any further performance
>>> questions.
>>>
>>> 73,
>>> Wayne
>>> N6KR
>>>
>>>
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