Topband: Waller Flag Question

[Tom W8JI]

> I would just like to understand what Tom is saying. I almost think he had
> noise figure confused with noise temperature at one point.
>
> Correction to my previous e-mail, first sentence in second paragraph.
> should have said "When I studied preamps and NF ~30 years ago, I thought
> the NF of the first active device (preamp) was the all-important thing".


With proper conversion, noise figure, MDS, and noise temperature are 
interchangeable in overall use or meaning.

People in this thread are working in noise figure and gain when considering 
preamplifiers, so I stayed there.

40 dB is a whole lot of gain in front of a normal receiver. To me, it looks 
like the 40 dB is unrealistic unless the receiver is lacking normal gain. In 
a common receiver, if 40dB gain is required, the antenna system is going to 
be more difficult to deal with than almost all can handle.

I'm only specifically speaking about the amount of gain. Don't read more 
into this than specifically what I am saying. (Which people have a tendency 
to do.)

73, Tom