Re: TV preamp FET choice (follow up with more impedance stuff)

From: Ken Smith (kensmith_at_green.rahul.net)
Date: 08/31/04 

Date: Tue, 31 Aug 2004 01:52:40 +0000 (UTC)

In article <ch0k1c$1npv$1@news.iquest.net>,
John S. Dyson <toor@iquest.net> wrote:
[...]
>I strongly suggest looking at devices with input impedance that is fairly
>close to 50 (or 75) ohms.

If you can't find 50 or 75 ohms, try for twice that and parallel two of
them.

[...]
>For low noise RF applications, you probably want to try to find components
>whose input impedance is within 2:1 or 4:1 of the source impedance.

Better yet, look for one where the maker elected to put the noise at
the impedance level you need on the first page of the data ***.
Component companies always (mostly) try to make their part look the best.
As a result, they put the characteristics that are good on page one. 

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