More Re: [TenTec] Orion redefines the meaning of ... AGC OFF

[Michael Tope]

Actually what Sinisa is suggesting is not just mental monkey
spanking, it is a very good test. If you don't hear an increase
in background noise when you connect your antenna, your
receiver quite likely has a noise figure which is too high
for the band conditions and antenna your are using. If that
is the case, you may never hear the very weak signals that
are above the band noise, but below the receiver's thermal
noise. Using this test also saves you from wasting time trying
to get a 1dB noise figure from a 1.8 MHz receiver  which will
be connected to transmit antenna in an urban environment
where the band noise could be 30 or 40dB higher than
the thermal noise coming from a resistor at 100 Kelvin
(e.g. 1dB NF).

BTW, in industry, noise figure is almost always measured
using a broadband noise source. CW signals are seldom
used.

73 de Mike, W4EF..................


----- Original Message -----
From: "Rick Westerman" <Rick at dj0ip.de>
To: <tentec at contesting.com>
Sent: Sunday, February 08, 2004 12:26 PM
Subject: RE: More Re: [TenTec] Orion redefines the meaning of ... AGC OFF


>
> Hey Sinisa, what in the world are you trying to prove now?
>
> "Can I recommend a more repeatable noise figure test,
> which even doesn't require any signal on the band?"
>
> What is your point?  Who among us is interested in tests which do
> not require a signal on the band.  I assume we are all in this
> game to hear signals on the band.  What you are suggesting is
> nothing more than mental masturbation.  Sorry for the French but
> that's the only words I can find for this situation!
>
> Sorry Sinisa, this time I just can't see your point!
>
> 73
> Rick
>
>
>
>