Fw: Re: Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line
Sandy and Kees Talen
[email protected]
2002年12月13日 09:48:07 -0600
People always ask me why I'm concerned about a few dB attenuation
because 3dB is only half an S-unit and no one will ever be able to
tell the difference. That's true relative to the S-units, but may make
the
difference between copy and poor copy. For -3dB, what the receiver
sees is a 30% less signal voltage at the antenna terminals. To put it
into perspective, the typical 100W Tx with a 1KW linear only
produces a difference of 1.67 S-units.
Let's look at it from the other end. If someone has a "30 over S9" signal
and he's running 1KW, he could reduce his power to ONLY 1W and
still be "S9". Also using a linear to go from 100W to 1KW will
improve your signal 10dB or the same guy using the linear for
"30 over S9" would get "20 over S9" without the linear.
73 Kees K5BCQ