----- Original Message -----
From: "james moritz" <[email protected]>
To: <[email protected]>
Sent: 17 January 2005 13:45
Subject: LF: RE: Re: Re: SWR-off topic
There are a bewildering array of modifications to the Smith chart, including
expanded regions of low or high SWR, an inverted form with unity SWR at the
outer edge of the chart (very odd scales on that one!) and versions for
negative resistance (apparently useful for tunnel diode designs).
Ah Jim, you have to remember maybe before and certainly after 1940 the
common line amplifier in telephone trunk networks was a "Negative Resistance
amplifier" . These were certainly used a lot in by GPO Telephones the UK and
almost certainly by the Bell System. This is even before tunnel diodes were
discovered/invented in the later 1950s. . A lot of the technicians and
engineers would have got their training as radio and radar mechs in the
forces.
Cheers de Alan G3NYK
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