[Elecraft] K3 and phase noise

[Eric Swartz - WA6HHQ, Elecraft]

Hi Bill,

The reference on-channel signal for past ARRL BDR testing has typically 
been set between -110 and -80 dBm, well above the MDS. te interfering 
signal generator is increased until this signal drops by a dB due to 
compression. This on frequency signal dominates the in-band RMS audio 
voltage. The noise floor needs to raise a lot before it dominates that 
signal.

Also, even on the Orion, their BDR is well above their phase noise at 
any spacing.

For the Orion II, the ARRL numbers are:

               2kHz   20kHz
Phase Noise    -129  -125
BDR             136   136
Neither of their BDRs were noise limited.

For the particular K3 I tested the phase noise on below, I measured a 
typical BDR of 140-141dB at spacings 5 kHz and wider and about 138dB at 
2 kHz.

On another note, as I mentioned in my email, the ARRL has refined a 
number of their test methods. They are now making the dynamic range 
measurements by measuring the on frequency IMD spur or blocked signal 
using a narrow band spectrum analyzer. This separates the blocking or 
IMD measurement from  reciprocal mixing, which they will do as an 
additional test. See page 71 of the May 2006 QST for details.

73, Eric   WA6HHQ
-----

Bill Tippett wrote:
> WA6HHQ:
>
> Rig     1kHz    2   10   20   50   100   1M
> K3      -110  -119 -136 -140 -143 -144  -150
>
>         I'm now wondering how you measured 143 dB BDR at 2 kHz in the 
> presence of 119 dB Phase
> Noise?  Shouldn't the measurement have been
> "phase noise limited"?
>
>                                 73,  Bill  W4ZV
>