[Elecraft] FTDX5000 Design Flaw

[Paul Christensen]

I just spent some time reviewing phase noise data for competing 
transceivers.  The P/N plot at 1 kHz(Fc) and beyond of the FTdx5000 as show 
in the December, QST product review looks no worse than the IC-7700, 
IC-7600, Flex 5000A, Orion II, and Yaesu FTdx9000 series.  So, any design 
limitation evident in the Yaesu FTdx5000 is something that needs to be 
addressed by most manufacturers.  Arguably, the mediocre P/N result is 
really a design limitation, rather than a design flaw.  I would think that 
if the problem was pervasive, it would show at contest stations like K3LR, 
where IC-7700/7800 transceivers are used.

But to your point, the K3 does excel in this metric and the competition 
should do a better job with its future designs as well as placing more 
importance on Tx IMD optimization.  Yaesu's success in their implementation 
of Class A amp design is clearly evident -- but it's an inefficient way to 
get to those Tx IMD numbers.

Paul, W9AC