[Elecraft] K-2 vs SDR-1000

[Eric Swartz - WA6HHQ, Elecraft]

Hi Bill,

The ARRL has not published lab tests on the SDR-1000 to my knowledge, 
but I do have one here in the lab.

Its an interesting approach for a 100% computer based rig and in general 
its RX performance is not too bad, but is is well below the K2 for IMD 
dynamic range and Blocking dynamic range.

It relies on the sound card in the PC to do all of its filtering, which 
makes it's performance quite variable depending on what quality sound 
card is in use and how it is set up by the user. In any case though, the 
current PC sound cards do not have enough A/D input range to get the 
same dynamic range performance as rigs (like the K2, Orion. etc) that 
use narrow crystal filtering at their first IF.

It also uses a direct DDS based local oscillator (without a following 
PLL to clean it up) for its VFO, which will have numerous significant 
off freq spurious responses in the -80 to -90 dB range that will mix off 
frequency signals onto your listening frequency. These spurious receive 
components absolutely can not be canceled out by the DSP once they 
occur. They look identical to legitimate on-frequency RX signals to the 
DSP. As a comparison, the K2 and other top performing rigs have local 
oscillator noise (with no spurs) at -125 to -130 dBc range five to ten 
kHz from the carrier. A big difference.

Even more important, the direct DDS approach creates the same DDS off 
freq. spurs on transmit. Not a great idea then running 1KW etc.

73, Eric   WA6HHQ



Bill_Harris wrote:
> Have there been any lab tests published comparing the SDR-1000 against the K-2?
> 
> Carry on
> 
> Bill_Harris 
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