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1994-06-04
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Date: Sun, 13 Feb 94 04:30:28 PST
From: Ham-Homebrew Mailing List and Newsgroup <ham-homebrew@ucsd.edu>
Errors-To: Ham-Homebrew-Errors@UCSD.Edu
Reply-To: Ham-Homebrew@UCSD.Edu
Precedence: Bulk
Subject: Ham-Homebrew Digest V94 #28
To: Ham-Homebrew
Ham-Homebrew Digest Sun, 13 Feb 94 Volume 94 : Issue 28
Today's Topics:
100hz tone board (2 msgs)
Aluminium
Power supply design questions (sort of long) (2 msgs)
Securing VXO coils, what glue?
spot my transistor.
Send Replies or notes for publication to: <Ham-Homebrew@UCSD.Edu>
Send subscription requests to: <Ham-Homebrew-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
Archives of past issues of the Ham-Homebrew Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew".
We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
----------------------------------------------------------------------
Date: 11 Feb 1994 20:49:43 GMT
From: elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!howland.reston.ans.net!sol.ctr.columbia.edu!news.columbia.edu!bonjour.cc.columbia.edu!mac20@ames.arpa
Subject: 100hz tone board
To: ham-homebrew@ucsd.edu
Acutally i missed the beginning of this thread but concerning PL Tones,
is there a simple chip or method that will decode PLs? I know there's
the chip for DTMF from SSI but i'm wondering if there is something for
sub-audiable also.
Mike KF2NV
------------------------------
Date: Thu, 10 Feb 1994 19:30:13 GMT
From: mvb.saic.com!unogate!news.service.uci.edu!usc!sdd.hp.com!col.hp.com!news.dtc.hp.com!hplextra!hpcss01!markb@network.ucsd.edu
Subject: 100hz tone board
To: ham-homebrew@ucsd.edu
check the back of QST, there are a couple of manufactures of nice little
boards (about $50 I think), you can build a simple 100Hz osc and inject
that into your input audio, it is hard to build one that doesn't drift
though, a Wein Bridge osc is OK but the XTAL controlled boards are better,
I'd buy one, then you can change the freq if you need to, the have little
jumpers or switches to set the correct PL,
the 100Hz needs to be abouut +/- 1 Hz, people on the air can help you
set the deviation level.
good luck
------------------------------
Date: Fri, 11 Feb 1994 19:22:50 GMT
From: agate!howland.reston.ans.net!europa.eng.gtefsd.com!paladin.american.edu!constellation!osuunx.ucc.okstate.edu!olesun!gcouger@ames.arpa
Subject: Aluminium
To: ham-homebrew@ucsd.edu
In article <tgmCL01Dq.Ito@netcom.com>,
Thomas G. McWilliams <tgm@netcom.com> wrote:
>Jim Buchanan (c22jrb@kopt0002.DElcoelect.COM) wrote:
>: I'm looking for a mail-order source for aluminium
>: sheets to be used in making panels and cases for
>: homebrew eqpt. All local sources I can find have
>: minimum orders geared towards manufacturing firms.
Junk yards often have surplus aluminium and odd size
peices. Watch for hardened Al sheet it breaks insted
of bending. It can be annealed by heat.
Also try to find out who the local sources are selling
to. And buy their scrap.
Gordon AB5Dg
------------------------------
Date: 11 Feb 1994 20:02:37 GMT
From: agate!msuinfo!cravitma@ames.arpa
Subject: Power supply design questions (sort of long)
To: ham-homebrew@ucsd.edu
I am trying to design a regulated 12V power supply (to power my HT at
home) and need advice on the following (since it's been a long time
since I have designed P.S's and am going from memory). Here is the
circuit I have so far:
+----Fuse-+-Switch--+
| | |X+--------+ +---Diode---+
Plug --| MOV |F| Bridge | |
| | |M| +Rectifier+---+--+-+-Regulator-++--->
| | |R+---|----+ | | | |
+---------+---------+ | C1 = = C2 | = C3
| | | | |
+-------------+--+-------+------+--->
The secondary of the transformer is going to be around 14V 1.5 A, and
the regulator will be a 7812.
My questions are:
1) Have I overlooked anything electrical-wise or safety-wise
in the circuit? As I said, it's been a couple of years since I
designed a P.S. and I was going from memory here.
2) What are the values of C1, C2 and C3? (Capacitor type,
capacitance and voltage ratings)
3) Can the 7812 handle 1.5 - 2 A of current? If not, is there
another fixed 12V regulator I can use (I don't want to use an
adjustable regulator for reasons of cost and simplicity of
circuit design)
If anyone can provide comments, suggestions, criticisms, pointers to
references, etc, I would greatly appreciate it.
/Matthew N9VWG
--
Matthew Cravit, N9VWG | All opinions expressed here are
Michigan State University | my own. I don't speak for Michigan
East Lansing, MI 48825 | State, and they don't speak for me
E-Mail: cravitma@cps.msu.edu | (thank goodness).
------------------------------
Date: Sat, 12 Feb 1994 17:13:54 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!emory!kd4nc!ke4zv!gary@network.ucsd.edu
Subject: Power supply design questions (sort of long)
To: ham-homebrew@ucsd.edu
In article <2jgo8t$17cu@msuinfo.cl.msu.edu> cravitma@cps.msu.edu (Matthew B Cravit) writes:
>
> 3) Can the 7812 handle 1.5 - 2 A of current? If not, is there
> another fixed 12V regulator I can use (I don't want to use an
> adjustable regulator for reasons of cost and simplicity of
> circuit design)
The standard 7812 can't handle that much current, it's rated at 1.5A
max, but there are "high current" versions that can handle up to 5 amps.
They're usually the ones in the TO-3 cases and have the 'K' suffix on
their part numbers.
Gary
--
Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary
534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | |
------------------------------
Date: Wed, 9 Feb 1994 05:20:00 GMT
From: netcomsv!netcom.com!tgm@decwrl.dec.com
Subject: Securing VXO coils, what glue?
To: ham-homebrew@ucsd.edu
asirene@ntuvax.ntu.ac.sg wrote:
: I am winding some coils for a VXO and want to know if
: the "glue-gun" melted plastic is suitable for securing the coil
: or if it is too lossy?
The classic solution is Q-dope made by dissolving polystyrene
in a solvent. Polystyrene is plentiful but I can't remember
the proper solvent. I made a gooey useless mess once when I
used a less than optimal solvent. Acetone should work.
Thomas
------------------------------
Date: Wed, 9 Feb 1994 05:12:51 GMT
From: netcomsv!netcom.com!tgm@decwrl.dec.com
Subject: spot my transistor.
To: ham-homebrew@ucsd.edu
antonio gatta (st92ba44@dunx1.ocs.drexel.edu) wrote:
: the most convenient place for me to get such pieces is at a local
: radio shack. ..the catalog has alot of transistors...all marked either NPN
: or PNP. i haven't spotted a HEP 232 (?). which one do i need? it gives
: no voltage specs or anything. can i use just any old NPN? any help would
: be appreciated. thanks.
The HEP line was made by Motorola and I believe HEP means "Hobbyist
and Experimenters Parts". My NTE book says it is equivalent to an
NTE 121 a PNP power transistor in a TO-3 case, 30v c-e, 100 watts.
It is also germanium. The closest radio shack equivalent would
be a part # 276-2043. You might have to twiddle with the biasing slightly
because the RS part is silicon. Generally transistors for this sort
of application are pretty non-critical as long as you have the
approximate power dissipation and collector voltage.
Thomas -- KI4N
------------------------------
End of Ham-Homebrew Digest V94 #28
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