Re: I: [amsat-bb] Input impedance of DEMI2400-144RX?

[Glenn Little <glittle@xxxxxxxx>]

Not free but almost.  See 
http://www.its.caltech.edu/%7Emmic/puffindex/puffform.html

73
Glenn

At 06:15 PM 7/29/01 -0400, Anthony Monteiro wrote:
>Hi Domenico,
>Where can you download PUFF? I would love to have a copy.
>Thanks,
>Tony AA2TX
>---
>At 09:57 PM 7/28/01 +0200, i8cvs wrote:
>
>>  Hi  Scott,
>>
>>  If the input device of DEMI2400-144RX is a GaAsFET and if the input network
>>  has been adjusted for the lowest Noise Figure to 50 ohm input,than the
>>  reflection coefficient S11 allow you to get at best a return loss of
>>  3 to 4 dB or an input VSWR very high around 5 or 6.
>>
>>  Such high input VSWR is normal in a devices such a GaAsFET adjusted for the
>>  lowest Noise Figure.
>>
>>  If you look at the scattering parameters of a GaAsFET for minimum noise ad
>>  make an exercise using PUFF,Computer Aided Design for Microwave Integrated
>>  Circuits Version 2.0 you will get the answere to your question.
>>
>>  PUFF is widely used in Europe and originated as a teaching tool for
>>  Caltech's microwave circuits course by professors:
>>
>>  Scott W. Wedge
>>  Richard Compton
>>  David Rutledge
>>
>>  PUFF Distribution
>>  Electrical Engineering M/S 116-81
>>  California Institute of  Technology
>>  Pasadena, CA 91125
>>
>>  FAX to (818) 356-2137
>>  73 de i8CVS Domenico
>>
>>
>>  ----- Original Message -----
>>  From: Scott Townley <nx7u@arrl.net>
>>  To: <amsat-bb@AMSAT.Org>
>>  Sent: Monday, July 23, 2001 1:37 AM
>> > Subject: [amsat-bb] Input impedance of DEMI2400-144RX?
>> >
>> >
>> > Has anyone measured the input impedance/VSWR of the DEMI 2400-144RX
>> > downconverter?
>> > Trying to assess whether mine is nominal or not.
>> > So far have measured 20dB conversion gain but input VSWR is very high,
>> > which may mean nothing depending on the design philosophy.
>> > TIA,
>> > Scott Townley
>> > nx7u@arrl.net
>> > ----
>> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>>
>>
>>
>>
>>
>>
>>
>>
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>
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
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Glenn Little                         glittle@awod.com   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv@amsat.org   AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)                      ARRL  TAPR
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