[Elecraft] KX3 "Full" SDR

[Bruce Beford]

> For those, the noise from a Flex at 100w, at -77 dBc (which is -27 
> dBm), can be quite substantial. Recall that S9 is approx -72 dBm. A 
> Flex is transmitting wideband S9+45 noise.

OK, I'm not a Flex user. But, I don't agree with your math. I am not trying
to defend the transmitted phase noise performance of the Flex products,
but... Your math is flawed.

Assume 100w transmitter is delivering +50 dBm to an antenna. (100W is 50 dB
greater than 1 milliwatt) Also assume you are at a receiving station, and
hearing this station at S9+30 dB, on a receiver calibrated to 6dB/S unit,
S9=50uV at 50 Ohms, or -73dBm for S9. Your receiving the fundamental signal
at -43dBm (S9+30dB). With the transmitted phase noise 77dBbelow the carrier,
it would be received at -120dBm, or about S2.

Granted, it would be 10 dB stronger (abt S3.5), if you were receiving the
fundamental transmission at S9+40dB, etc. But... the Flex is not "
transmitting wideband S9+45 noise."

Let's not blow this out of proportion.

Bruce N1RX