[TenTec] SDR-1000 MDS

[Bill Tippett]

         Just a quick note to clarify this.  Lee W9OY
first mentioned MDS of -160 dBm (measured with the new
Janus soundcard not yet in production).  From the Janus
webpage I referenced previously:

"Noise Floor = -160dBm (in an 11Hz FFT bandwidth)"

The parentheses are important because we must
normalize noise bandwidths to 500 Hz to compare to
traditional 500 Hz BW MDS around -140 dBm (e.g.
Orion & IC-7800, preamp on, are in this ballpark).

         To normalize BWs, we use: 10 log (BW1/BW2).
To normalize the 11 Hz MDS above to 500 Hz, we add
10 log (500/11) or 16.6 dB.  Thus the comparable MDS
is -160 dBm + 16.6dB = -143.4 dBm, which is in the
same ballpark as existing rigs.  -160 dBm was only
a measurement of the ADC itself and there could be
other adjustments before we see a published MDS for
the overall receiver.

         Bottom line, I don't believe MDS will
be significantly different from existing rigs.  IMD
will likely be much better but BDR may be a little
worse (my guess).

                                 73,  Bill  W4ZV