[amsat-bb] Re: GAAS FET Preamp Component Question

i8cvs domenico.i8cvs at tin.it
Mon Feb 27 03:25:43 PST 2012

Hi Gene, KB3ONA

As described into your Handbook at page 10.30 Chapter 10, the ferrite
bead is slipped over the drain lid of a GaAsFET to prevent a possible
autooscillation of your MGF-1402 and in your case a ferrite bead of
Fair-Rite no.43 material is expecially suitable for this purpose.

BTW any ferrite bead of 3 mm in diameter is suitable provided that the
ohmic resistance of material as measured with an ohmmeter across the
ends of the single hole is around 30 K

Take care when handling a GaAsFET as it is very sensitive to static
charges on your hands so that all working tools and as well your body
must be grounded in order do not destroy the device.

In addition if your solder iron is not a low voltage 12 volt AC statically
insulated from the AC line for solder GaAsFET's and active devices
it is recommended to solder the GaAsFET at the end of the job using the
solder iron sufficiently hoth but disconnected from the AC line supply.

Have fun.

73" de

i8CVS Domenico

----- Original Message -----
From: "Eugene Crist" <ejcristjr at gmail.com>
To: <amsat-bb at amsat.org>
Sent: Monday, February 27, 2012 3:41 AM
Subject: [amsat-bb] GAAS FET Preamp Component Question

> I'm planning to build the GAAS FET Preamp for 430 MHZ that's in the 2008
> ARRL Handbook on page 14.37. One of the components on the drain of Q1
> looks like a ferrite bead. I've never used these in construction before
and the
> parts list doesn't specify any particular value or rating.
> Does anyone know what value/rating should be used? Any info would be
> greatly appreciated.
> Thanks, Gene (KB3ONA)
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