Topband: dynamic range

[Sinisa Hristov]

Jim Jarvis wrote:

> 1)  What's s9? I've got references indicating 50uV or 100uV.


It's 50 uV into 50 Ohm load.
Unloaded generator has 100 uV.


>         100uV plus 60dB is....gee...100V! A very large signal, indeed.

100uV plus 60dB is 100 mV.


>         A mere 30dB down from 100uV brings you to .1uV

It takes 60 dB from 100 uV to 0.1 uV.


> 2)  Who among us has a receiver which is calibrated in dBm?

I dream about it :-)


>         Who among us trusts the logarithmic calibration of their
>         wiffy-unit meter, really?  And over how many decades of
>         its range? (regardless of indicated units.)

My MkV can be reasonably trusted on 14 MHz from S8 to S9+50 dB
with preamp on and attenuator off.


> 5)  Interesting if the new Tentec claims -140dBc/Hz noise output.
>         Add 10dB for an amp..still impressive

Preamplifier has nothing to do with phase-noise specification.


73,

Sinisa  YT1NT, VA3TTN