[HomeBrew] Re: HomeBrew Digest, Vol 11, Issue 4

[Jim & Velma Woods]

----- Original Message -----
From: <homebrew-request at mailman.qth.net>
To: <homebrew at mailman.qth.net>
Sent: Wednesday, December 08, 2004 1:00 AM
Subject: HomeBrew Digest, Vol 11, Issue 4


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> Today's Topics:
>
>    1. Spray etcher (Loren Moline WA7SKT)
>    2. An RF Pre-amp design question (Philip Atchley)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 07 Dec 2004 09:25:08 -0800
> From: "Loren Moline WA7SKT" <lmoline at hotmail.com>
> Subject: [HomeBrew] Spray etcher
> To: homebrew at mailman.qth.net
> Message-ID: <BAY15-F20C397589DA86FE637335DAFB50 at phx.gbl>
> Content-Type: text/plain; format=flowed
>
> Could someone tell me where I can get a small chemical pump that will pump
> ferric chloride so I can make a spray etcher?
>
>
> Loren
>
>
>
> Loren Moline WA7SKT  CN86cx
> Member: ARRL, Pacific Northwest VHF Society #151
> 2 Meter EME initials = 52
> 2 Meter EME with 4 X K1FO - 12's, RG-218 7/8"  coax,  IC-820H, and 380W
from
> TE Systems 1452G
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 7 Dec 2004 20:55:28 -0000
> From: "Philip Atchley" <beaconeer at mercednet.com>
> Subject: [HomeBrew] An RF Pre-amp design question
> To: <homebrew at mailman.qth.net>
> Message-ID: <000f01c4dc9f$18933d70$95e206d8 at ko6bba1e64d2b6>
> Content-Type: text/plain; format=flowed; charset="Windows-1252";
> reply-type=original
>
> Hi,
>
> I have a Superior Instruments (??) Genometer (signal generator) model
> TV-50A that I've repaired and which works, but in reality is a rather
> poor test instrument for general radio work.  Not overly stable and
> the tuning knob being directly on a variable capacitor shaft with no
> vernier makes it nearly impossible to set "accurately" enough.
> Probably ok at IF and BCB frequencies, but that's about all.
>
> HOWEVER!  It DOES have a NICE RF deck containing a bandswitch and
> tunes 100KC to 60MC in 5 ranges (the 45-180MC range is really a third
> harmonic of range 5).  The coils each have a tap (for Hartley Osc)
> with the cold end grounded directly and the bandswitch selecting both
> coil and tap (naturally).  It uses a 12AT7 Oscillator tube.
>
> I've been wanting to build a NICE tunable RF preamp for the shortwave
> range (I have already built one for 17-530 KC) but have been putting
> it off due to not having all the parts and cabinet on hand (and a
> tight budget).
>
> THIS THING IS CRYING TO BECOME AN RF PRE-AMP 8^) Here are some
> thoughts I've had on the matter. In all cases the RF deck, tuning
> capacitor and cabinet would basically be used intact, removing the
> oscillator circuit and subbing a RF amplifier.
>
> 1.  First thought was a TUBE Pre-amp, perhaps a cascode one using
> something like a 6BQ7 tube that would fit in the present tube socket
> (but which I'd have to BUY).
>
> 2.  I've given up that idea and am considering a J310 High Impedance
> FET input stage followed by either a bipolar transistor emitter
> follower OR J-310 FET input stage followed by a MAR-6 mmic (of which
> I've been given a few).  In the latter case the FET would probably be
> wired as a "Source Follower" and provide the impedance matching to the
> relatively low input Z of the MAR (which has about 20dB gain and 3dB
> noise figure).
>
> 3.  The present dial calibration should remain sufficiently accurate
> (especially as the coils are adjustable) and the large cabinet with
> it's "bonus" holes would be useful for providing things like a
> receiver select switch, Attenuators, 100KC Xtal calibrator etc. With
> LOTS of room top spare I shouldn't have any problem providing
> sufficient internal shielding for stability etc.
>
> An additional advantage of the solid state version would be 12 Volt
> operation off the station battery bank instead of 110VAC.
>
> What are the "thoughts" of folks out there concerning this "project"?
> I'm sure it'll work electrically, but maybe some folks have better
> circuit suggestions.
>
> 73 de Phil,  KO6BB
> http://users.mercednet.com/beaconeer/
> Merced, Central California, 37.3N  120.48W  CM97sh
>
>
>
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> End of HomeBrew Digest, Vol 11, Issue 4
> ***************************************
>