[Elecraft] K3 or SDR-5000?

[Bill W5WVO]

Richard Smith wrote:

> There is an earlier thread about K3 vs. Flex-5000A in the Elecraft reflector 
> archives from October 2007.  Search "5000A" and you should find them.  They 
> are worth reading, as they go into some depth about
> the issues, questions and misconceptions that keep coming up.

Agreed. I went and looked them up in my own archive from October, and found an 
excellent post by Bill Tippett, W4ZV, on the relative dynamic range 
performance of the two systems (10/6/2007).

One thing that must be pointed out, however: When W4ZV posted in early 
October, the FLEX-5000A was quoted as having an IMD3 at 2 kHz of 96 dB. 
According to the current FLEX website, they are now claiming a 14 MHz IMD3 at 
2 kHz spacing of >100 dB using ARRL measurement methods. This puts it 6 dB (or 
more) better than the K3 at 2 kHz spacing, assuming identical measurement 
methods. I think it's arguable whether even a 6 dB difference in IMD3 is 
meaningful when both are well above 90 dB, but there it is. Comments on this 
thought would be interesting.

However, FLEX does not mention anywhere on their website what their BDR is, 
and I would have to assume that is because their performance on this metric 
isn't a world-beater. W4ZV's October post quoted a flat BDR spec of 123 dB, 
which is nearly 20 dB worse than the K3's 5 kHz spec. I would think that for 
blocking DR in a very strong signal environment like many contests, that 20 dB 
could be more significant than a 6 dB difference in IMD3.

Only side-by-side comparison on the bench and in a real-world operating 
environment can say for sure, and I'm looking forward to that.

Bill / W5WVO
K3 in Febrary 2008