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R: Conductive Foam, was Re: How far should one separate a LNA and its associated down converter, and Why?



Hi

I have my tubes SSB old and honourable TX Geloso G4/225 that i bought
before to be married 36 years ago and i currently use it in 28-30 MHz to
drive a 435-436 MHz transverter for the uplink in U band.

Anyone like to contact me on AO40 tomorrow 8 april orbit 1119 between
MA 200 to MA 240 ?

TNX

73" de i8CVS Domenico

----- Original Message -----
From: Rick Vidmar - K9KK <k9kk@earthlink.net>
To: Dr. Jim Akers <jakers@ECE.MsState.EDU>; Bill Acito W1PA
<w1pa@hotmail.com>
Cc: i8cvs <domenico.i8cvs@tin.it>; AMSAT-BB <amsat-bb@AMSAT.Org>
Sent: Monday, April 07, 2003 8:28 PM
Subject: Re: [amsat-bb] Conductive Foam, was Re: How far should one separate
a LNA and its associated down converter, and Why?


> I HAVE MY 1ST CK722 ALSO---I USED IT AS AN AUDIO AMPLIFIER
> ON MY CRYSTAL RADIO SET ABOUT 51 YEARS AGO
>
> ----- Original Message -----
> From: "Dr. Jim Akers" <jakers@ECE.MsState.EDU>
> To: "Bill Acito W1PA" <w1pa@hotmail.com>
> Cc: "i8cvs" <domenico.i8cvs@tin.it>; "AMSAT-BB" <amsat-bb@AMSAT.Org>
> Sent: Monday, April 07, 2003 10:13 AM
> Subject: Re: [amsat-bb] Conductive Foam, was Re: How far should one
separate
> a LNA and its associated down converter, and Why?
>
>
> What?! A ham throws something out???  Really hard to believe ,Bill:)  I
> still have the first CK722 Transistor that I bought and that was when they
> first came out at about $15.00 a pop!! That should tell you something
> about my age:) My XYL gave up on me years ago and just lets me keep the
> stuff.
>
> 73...Jim...W5VZF.
>
>
>
>
> Dr. Jim Akers
> Dept. of Electrical
> and Computer Engineering
> Miss. State Univ.
>
>
> On Mon, 7 Apr 2003, Bill Acito W1PA wrote:
>
> > Thanks Domenico.
> >
> > I'm sitting here thinking of all the sheets of this stuff I have tossed
> > out after buying parts and such. Now I don't have any. Where can I buy
> > this stuff?
> >
> > Bill
> > w1pa
> >
> >
> > ----- Original Message -----
> > From: "i8cvs" <domenico.i8cvs@tin.it>
> > To: "Bill Acito W1PA" <w1pa@hotmail.com>; "AMSAT-BB"
> > <amsat-bb@amsat.org>
> > Sent: Monday, April 07, 2003 10:23 AM
> > Subject: R: [amsat-bb] Re: How far should one separate a LNA and its
> > associated down converter, and Why?
> >
> >
> > >
> > > ----- Original Message -----
> > > From: Bill Acito W1PA <w1pa@hotmail.com>
> > > To: <amsat-bb@AMSAT.Org>
> > > Sent: Monday, April 07, 2003 4:47 AM
> > > Subject: [amsat-bb] Re: How far should one separate a LNA and its
> > associated
> > > down converter, and Why?
> > >
> > >
> > > > > I also experienced 13ULNA preamp instability and solved it by
> > putting
> > > > a 1"
> > > > > square piece of black anti-static foam in the DEM enclosure.  It
> > was
> > > > about
> > > > a
> > > > > 1/4" thick.  My 13ULNA is connected to my downconverter through a
> > > > double
> > > > > male N barrel connector.
> > > > >
> > > >
> > > >
> > > > While I am digging up the QEX reference, can the same thing be
> > > > accomplished by putting additional shielding (a copper or brass
> > plate)
> > > > immediately over the ULNA board, in close proximity? I worry about
> > the
> > > > foam breaking down and shedding.
> > > >
> > > > Bill
> > > > w1pa
> > > >
> > >
> > > Bill,
> > >
> > > Additional shielding inside the box immediatley over the LNA board do
> > > not prevent the RF energy to transfere from one stage to the previous
> > > one inside the box.
> > >
> > > On the other hand the conductive black foam absorbes and dissipates
> > > the circulating RF  fields inside the box and it make very easy to cut
> > > regenerative feedback  between the input and output of low signal  and
> > > high gain amplifiers.
> > >
> > > Dont worry about the possibility of foam breaking down is you use a
> > > good quality elastic glue like BOSTICK for example.
> > >
> > > 73" de i8CVS Domenico
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!


> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>







----
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