QRZ! Ham Radio 5/QRZ Ham Radio Callsign Database - Volume 5.iso/digests/homebrew/940326.txt

Internet Message Format | 1994-11-13 | 24KB

Date: Sat,  5 Nov 94 04:30:37 PST
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Homebrew Digest V94 #326
To: Ham-Homebrew


Ham-Homebrew Digest         Sat,  5 Nov 94       Volume 94 : Issue  326

Today's Topics:
                       Communications Quarterly
                            FM Crystal Set
                            Intermod Help!
                PCB Board from laser print?? (3 msgs)
Periodic Announcement - ARRL Email Information Server ([e-mail])
                            Quad Op Amp ??
            VCO in Key Components of Mod RCVR Design (QST)
                      Video Id'er .  need info.
             Where can I find a grid dip meter? (2 msgs)
                       Where does the power go

Send Replies or notes for publication to: <[e-mail]>
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Problems you can't solve otherwise to [e-mail].

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: Wed, 2 Nov 1994 19:17:50 GMT
From: [e-mail] (Minor_Cross)
Subject: Communications Quarterly

Ralf Gregory ([e-mail]) wrote:
: I recently found "Communications Quaterly" referenced in an
: technical article.
: What type of journal is it ? Where can I get it and what is the
: price?

Communications Quarterly is a publication of CQ Communications, Inc.
  76 North Broadway     Hicksville, NY  11801

Subscriptions are $29.95 per year, two yrs for $56.95 (USA)

73
Minor
--
  -------------------------------------------------     __
     Insert Standard Disclaimer notice here:           / /\
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Minor Cross   KD7YJ                           __     /_/ /\ \
                                             /_/\  __\ \ \_\ \
Integrated Circuits Business Division - CVO  \ \ \/ /\\ \ \/ /
1050 NE Circle Blvd                           \ \ \/  \\ \  /
Corvallis, OR  USA  97330-4299                 \ \  /\ \\ \ \
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Telephone: [phone] FAX:[phone]     \ \ \_\/ \ \ \
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e-mail: [e-mail]                           \_\/

------------------------------

Date: Sat,  5 Nov 94 03:12:00 -0400
From: [e-mail] (Hua Chu)
Subject: FM Crystal Set

MA>Message-ID: <[e-mail]>
MA>Newsgroups: rec.radio.amateur.homebrew
MA>Organization: ucsd usenet gateway

MA>Ian Mitchell asked how the crystal set works in digest #323.


Could you please tell me how I can get this digest? To what address do I
subscribe? Thanks for helping out a novice.

-H.C.

---
 * OLX 2.1 * Every time I lose weight, it finds me again!

------------------------------

Date: Thu,  3 Nov 1994 18:05:00 GMT
From: [e-mail] (Tom Alldread)
Subject: Intermod Help!

LB>I am running a Kenwood th-28a HT with a J-Pole antenna.  My problem
LB>is that  there is a cellular tower close to my current residence and
LB>my receiver is  picking up extreme intermod.  I am looking for any
LB>"cheap" or should I say  "homebrew" way of filtering out the
LB>intermod... Any help would be appreciated.

Greetings Loren:

    Fair Radio Sales in Lima, Ohio 419-223-2196 used to handle a
military surplus dual cavity bandpass filter F-194U that tuned 142-163
MHz. They also had models F-192U and F193U filters that could be
modified to cover the 2 M band. They were priced at less than $30 US
plus shipping. I do not know if they still have these filters available.

73

Very Best Regards,
T.M. Alldread        INTERNET: [e-mail]

---
* CmpQwk #UNREG* UNREGISTERED EVALUATION COPY

------------------------------

Date: Thu, 3 Nov 1994 12:43:06 +0000
From: [e-mail] (Ian G3SEK)
Subject: PCB Board from laser print??

In article: <[e-mail]>  [e-mail] (Sean
Norris) writes:
>
> I'm working on a project that requires me to make a PC board and I want
> it to be as hassle free as possible. I have seen many ads about some
> special paper which you can print with a laser printer, iron it onto the
> PC board, peel it off and then etch. Has anyone used this technique? If
> so, it it reliable? My project is all surface mount and at very high
> frequencies so the traces must be small and sharp.
> If anyone has any experience/tips/brands/etc. I would appreciate it very
> much if you could E-mail me.
In article: <[e-mail]>  [e-mail] (Sean
Norris) writes:
>
> I'm working on a project that requires me to make a PC board and I want
> it to be as hassle free as possible. I have seen many ads about some
> special paper which you can print with a laser printer, iron it onto the
> PC board, peel it off and then etch. Has anyone used this technique? If
> so, it it reliable? My project is all surface mount and at very high
> frequencies so the traces must be small and sharp.
> If anyone has any experience/tips/brands/etc. I would appreciate it very
> much if you could E-mail me.

Please post any good ideas to this newsgroup - we'd all like to know!

One potential problem with laser printers is that they don't
necessarily print with full geometric accuracy. For example, my old
LJII clone is OK across the page but has errors of up to 5% along
the length. This makes it very difficult to get the board mounting holes
on the right centers, and the pins of VLSI ICs can drift out of alignment.
Fortunately I know where the accurate zones are, so it's adequate for
small boards.

Moral: print out a 1"x1" grid and check it all over the page.


--
 73 from Ian G3SEK               |  Editor,  _The_VHF/UHF_DX_Book_
 Abingdon, England               |
 [e-mail]       | "In Practice" columnist for RadCom (RSGB)

------------------------------

Date: Thu, 3 Nov 1994 18:56:17 GMT
From: [e-mail] (Tom Bruhns)
Subject: PCB Board from laser print??

Ian G3SEK ([e-mail]) wrote:

(re: using a laser printer in making homebrew pc boards...)
: Please post any good ideas to this newsgroup - we'd all like to know!

Well, this isn't exactly what the original poster had in mind, but it works
well for me.  I make single and double sided boards, mostly surface mount
now.  Most of the parts I use are SOIC outlines with 50 mil lead spacing,
1206 and 0805 resistors and ceramic caps, tantalums, inductors, and things
like that.  Occasionally I'll do a fine-pitch part, though when doing that,
I don't rely on just the laser printer.

My process is photographic.  But it's pretty simple; from bare board to
etched blank is about 1.5 hours, including coating the board with
photoresist and drying it.  No darkroom is required, just dim lighting.
You can get pre-coated boards, too, to avoid dealing with the photoresist
lacquer and save the coating and drying time, about 45 minutes.

I can provide more details on the resist and its application, but will
emphasize exposure here:

I print a 1:1 flipped image of the design I want, with black where I want
copper on the board:  a "positive" image.  My photoresist is "positive"
type.  I print the image on a good quality tracing vellum.  It's
translucent, and by printing the image flipped, the toner goes against the
board and keeps the light diffusion in the paper from messing up the image.
The exposure is about 12 minutes under a sunlamp at about 15 inches, in a
simple print frame made of a large sheet of 1/4" plate glass and an
equal-size piece of foam rubber--it's about 15" square.  Just a simple
piece of plywood under it all to keep it flat.  The weight of the glass
against the board and paper, with the foam on the bottom of the board,
keeps the paper against the board.  After exposure, develop (in a dilute
sodium hydroxide solution) for about 2 to 3 minutes--in dim light it's easy
to see the development.  Rinse, scrub gently with a moist sponge with a bit
of cleanser (e.g., "Comet") on it.  Float on top of a tray of ferric
chloride to etch.

I have no trouble putting 8 mil traces/8 mil spaces on a board this way,
so I can do a single trace between SOIC pins.  I have done some
5mil/5mil stuff, but I print that 4:1 and have a litho shop make a 1:1
transparency for me for about $10.  A 600dpi laser printer might make 5/5
boards possible the "simple way."  My strange etch method has a reason:
as the etching takes place, convection currents are set up.  Gentle
though they are, they make the etching a bit faster and leave very clean
edges that are more vertical than if I just put the board on the bottom
of the tray.  You can float a board through the wonder of surface
tension.  I was surprised to see how well it worked when I first tried
it.  -- I got a lot of ferric chloride a long time ago, and though it's
not the ideal etchant, I'll use it till it's gone.  I'll probably switch
to cupric chloride when that happens.

For double-sided boards, I make two transparencies with alignment marks,
and tape them along one edge.  I then tape the board to one of the
transpariencies (which are quite a bit oversize) along two edges and lay
the other transparency over the top of the board.  That side is the
first to be exposed; the board is flipped and exposed to the
transparency it's taped to next.  You can do better with alignment if
you have a strip of material the thickness of the board that you can
align the transparencies to, using perhaps pins through
precision-punched holes like is done for things like archetectural
drawings that span several layers that must be kept in alignment.  But
using the simple tape-together method, I've used 30 mil pads on vias
successfully, and with surface mount, there's never a need for anything but
vias.  Careful layout keeps those to a minimum.

------------------------------

Date: 4 Nov 1994 14:08:24 -0800
From: [e-mail] (Ed Burress)
Subject: PCB Board from laser print??

In article <[e-mail]> [e-mail] (James D. Cronin) writes:
>             (stuff deleted)
>I've done toner transfer with regular paper and there are problems with
>the toner not sticking.  There is paper with a water soluble coating that
>is said to work well.
>
>Anybody know what the paper is coated with?
>
>73...Jim  N2VNO
>
>>Thanks,
>>Sean
>>
>
>

I have found that paper made for thermal wax transfer works well.
It has a clay coating which loosens up when placed in warm water.
I am soaking yet another batch for a Kenwood computer interface ala
QST Feb. '93 as we speak (read).  The particular paper I use is for
the Tektronix Phaser 200/220 series printers, since I work for them as
a Media Engineer.  I suspect that there are quite a few papers which
have a clay coating on the surface available at local paper supply
stores.  Many of these will be for thermal wax transfer, or ink jet type.

As an alternative, I have heard of people having good success by coating
the paper with a diluted solution of elmers glue and allowing it to dry
before printing on it.  I have not tried this, and don't really plan to
perform potentially terminal experiments on my laser printer.  Good luck.

Ed Burress
KC7GFX

------------------------------

Date: Wed,  2 Nov 1994 21:00:02 MST
From: [e-mail] (Michael Tracy)
Subject: Periodic Announcement - ARRL Email Information Server ([e-mail])

Periodic Announcement - ARRL Email Information Server ([e-mail])

The services that the ARRL provides via the internet include the
Email Information Server and the Technical Information Service.
The Information Server is an automated mail server that gives you
access to many of information files relating to various facets of
Amateur Radio.  You can retrieve any or all of these files by
sending an email message to [e-mail] here at ARRL HQ.
Each file you request is then mailed to you automatically.

To use it, mail messages to:

   [e-mail]

Each line of the message body should contain a command as shown below.
The subject of your message is not processed and may be omitted.  You
may place as many commands in a message as you want.  The files you
request will be sent to you in separate messages.  Only ASCII text
files are supported.

Valid INFO commands:

reply <address>  (may be needed - see below for explanation)
help
index
send FILENAME   (example: send prospect.txt)
quit

In the above message example, "help" retrieves a brief set of
instructions for info, "index" retrieves a list of available files
and "send prospect.txt" retrieves a text file containing information
on becoming a radio amateur.

Note to users with FTP capability:  All of these files are also
available by anonymous ftp to oak.oakland.edu in the
pub/hamradio/arrl/infoserver area.  Retrieve the file index.txt
in the /league sub-directory for a complete listing of available
files.

If you want to retrieve several text files with one message, use a
separate line for each "send filename" request.

Your From: field or Reply-to: field in your header should contain a
valid Internet address, including full domain name.  If your From:
field does not contain a valid Internet address, the answer will not
reach you.  If this is the case, then use the reply command as shown
above.  When needed, this command should always be the first command
in your message.

IMPORTANT: Please use the quit command in your message.  This will
           prevent processing errors from message signatures.

PLEASE NOTE!:  This is an automated system not capable of handling
written requests.  Any questions on the info-server or the content
of any of its files should be directed to [e-mail].

ALSO NOTE!: Do *NOT* reply to messages sent from [e-mail] - the
reply address is redirected to keep bounced messages from endlessly
looping.  Write a new message to [e-mail] instead.

The Technical Information Service gives League members on the
internet better access to the knowledgeable technical staff here
at ARRL HQ.  Questions relating to Amateur Radio and related
technical topics are welcome.  To use this service, send a normal
e-mail message to [e-mail] with your question spelled out in
plain english.  For best service, be as specific as possible and
keep your line length in messages to a maximum of 80 characters.
Due to personnel limitations, priority will be given to questions
from League members.

Best Regards,

Michael Tracy, KC1SX, ARRL Technical Information Services Coordinator
(e-mail [e-mail])


Sample of files available from INFO: (There are lots more!)

Note - If you are not yet an Amateur Radio operator retrieve the
file prospect (send prospect) for information on how to easily get
started in this fun hobby.

FILENAME         SIZE DESCRIPTION
 ---------------- ---- --------------------
PROSPECT.TXT       2k How to get your Amateur Radio license
EXAMS.TXT         52k Current exam schedule info - updated bi-weekly
EXAMINFO.TXT       9k Examinations - what to bring - requirements
USERS.TXT          6k List of HQ Email addresses
ARRLCAT.TXT       39k Catalog of ARRL Publications - commercial content
JOIN.TXT           2k How become an ARRL member
SERVICES.TXT       5k A condensed list of ARRL membership services
TOUR.TXT          28k An electronic tour of ARRL Headquarters
DIR.HQ             5k Visiting ARRL HQ - directions and tour information
HFBANDS            7k Breakdown of users of HF spectrum
Q-SIGS             1k ARRL list of Amateur Radio Q-signals
W1AW.SKD           2k W1AW schedule of transmissions and operation
PRODREV1.TXT      12k Which rig is best? Part 1 - QST Lab Notes
PRODREV2.TXT      22k Which rig is best? Part 2 - QST Lab Notes
!LIST.TXT          6k QST Bibliographies List
RFIGEN.TXT        37k How to solve an EMI/RFI problem - QST Lab Notes
RFISOURC.TXT      13k Where to buy filters - EMI-proof telephones etc.
ADDRESS.TXT       16k Lots and lots of ham/electronic company addresses
KITS.TXT           6k List of companies that sell kits
BBS.TXT           12k List of ham-radio land-line bulletin boards
FAQ1.TXT          25k Introduction to the FAQ and Amateur Radio
FAQ2.TXT          45k Amateur Radio Orgs, Services and Info Sources
FAQ3.TXT          32k Amateur Radio Advanced and Technical Questions

 -------------------------------------------------------------------
American Radio Relay League, Inc.     Tel: [phone]
225 Main Street                       Fax: [phone]
Newington, CT 06111                   Email: [e-mail]
 -------------------------------------------------------------------

------------------------------

Date: Fri, 4 Nov 1994 17:40:16 GMT
From: [e-mail] (David Walker)
Subject: Quad Op Amp ??

>Will the LM2900 work the same as the LM3900??

Yes, they are almost exactly the same; the 2900 has a wider temp. range, but
electrically they are essentially identical

>What other ideas ??

Sorry, I'm not familiar with the circuit so I can't help there. Good luck!

David WB4DJZ

------------------------------

Date: Thu, 3 Nov 1994 20:08:22 GMT
From: [e-mail] (Dave Newkirk (WJ1Z))
Subject: VCO in Key Components of Mod RCVR Design (QST)

Bill Kirkland ([e-mail]) wrote:

: Does anyone have any information on the design of the VCO diagrammed
: in the second part of the series "Key Components of Modern Receiver
: Design"? I am particularly interested in how the 9.2nH coil is tapped and
: any information on the source biasing scheme for the FET oscillator.

One thing's for sure: We relayed that inductor label incorrectly; the
correct value is 92 nH.

How about asking the author? The article's Endnote 10 (on page 31 of June
1994 *QST*) includes the phone [phone]) and fax [phone]) numbers
for Compact Software, of which author Ulrich Rohde is president.

David Newkirk, WJ1Z     [e-mail]

------------------------------

Date: 3 Nov 1994 22:51:58 -0800
From: [e-mail] (Dave Austin)
Subject: Video Id'er .  need info.

Am looking into getting one of those video id boards.  Was wondering
if it can put out black and white .  Looks like it just does white.
I wanted to make a id that you can kind of see through.  But would
need both b and w.   Easy to modify one.  The Elktronics is the only
one I know about.  Has anyone fooled with this?
TNX
Dave

------------------------------

Date: Fri, 4 Nov 1994 15:55:50 GMT
From: [e-mail] (Paul H. Bock)
Subject: Where can I find a grid dip meter?

[e-mail] (Al Richer) writes:

>Hello!

>After a hiatus of more years than I care to think about, I have returned to
>ham radio and construction of ham goodies. Unfortunately, I no longer own
>a grid-dip meter, and I can't seem to find one of the damned things anywhere.
>It's makin' it real hard to align converters....

>Can anyone tell me where I can purchase one of hese devices, or better yet,
>can someone point me toward a set of plans for same? I would prefer to build
>it myself, being the cheap swine that I am.....<grin>...

>                        Al Richer

     And please *post* the info rather than e-mailing to Al; I'd like
the info also, and there are no doubt others as well.

     73,

       Paul, K4MSG

------------------------------

Date: 3 Nov 1994 08:47:54 -0500
From: [e-mail] (Al Richer)
Subject: Where can I find a grid dip meter?

Hello!

After a hiatus of more years than I care to think about, I have returned to
ham radio and construction of ham goodies. Unfortunately, I no longer own
a grid-dip meter, and I can't seem to find one of the damned things anywhere.
It's makin' it real hard to align converters....

Can anyone tell me where I can purchase one of hese devices, or better yet,
can someone point me toward a set of plans for same? I would prefer to build
it myself, being the cheap swine that I am.....<grin>...

                        Al Richer

------------------------------

Date: 4 Nov 1994 17:22:40 GMT
From: [e-mail]
Subject: Where does the power go

In article <[e-mail]>,
Gary Coffman <[e-mail]> wrote:
>In article <3998nm$[e-mail]> [e-mail] (Guy Fletcher) writes:
>>
>>This is a rather different way of looking at the question,
>>hence the new thread. Considered comments welcome.
>
>If I may summarize, real power always flows
>towards the load, any heating in the amplifier is the result of
>loss of efficiency due to a poor load impedance at the amplifier
>output terminals. All else is chimera.

Hi Gary, unfortunately I can't find and don't remember Guy Flet's different
way of looking at things article that you quoted.

When I was in college, I ran an ARC-5 transmitter on 40m. It had two 1625
tubes. I turned it on one day and didn't know that my antenna had fallen
in a storm shorting the coax at the feed point. I had no SWR meter.
I listened, heard no signals, and started sending CQ. The parasitic
suppressors started smoking and the plates turned red.

If my 75 ohm coax had been infinitely long, I would not have known any
difference. The transmitter would have seen the normal 75 ohm load and
it did actually see that 75 ohm load for an instant until the reflections
from the short got back to the transmitter. If the impedance looking back
into the transmitter were zero or infinite, the tubes would not have gotten
hot. Therefore, there must be a real resistive component that caused a real
I2R loss within the tubes solely because of the reflections.

It helps to first visualize a perfect half wave dipole, ie purely resistive
with no reflections, and then imagine an irate neighbor driving a nail
through your coax exactly one half wavelength from the transmitter. The
resulting reflections are partially re-reflected and partially absorbed by
a real resistive component and dissipated within the transmitter tubes.
Eventually, all the power not dissipated in the coax will be dissipated
by the only "load" left in the system.

--
73, Cecil, KG7BK, OOTC   (All my own personal fuzzy logic, not Intel's)

------------------------------

Date: 5 Nov 1994 07:12:13 GMT
From: [e-mail] (Todd Little)

References<3 <[e-mail]>, <[e-mail]>
Reply-To: [e-mail] (Todd Little)
Subject: Re: THE LITTLE RAZOR BLADE RADIO (UPDATE)


How do you find the sensitivity of your radio?  I built one and find that
it isn't very sensitive and can't get it to tune anything other than
the loudest local station.  I'm guessing that both problems may be
attributable to using a low impedance earphone (all I had handy).  My
assumption is that the low impedance earphone lowers the Q so much of
the circuit that it is so broadbanded as to receive just about anything.

Does anyone know of a good source for inexpensive high impedance earphones?
I need about 20 of them for the radio club at the local elementary school.
I'm going to have them build one of these radios as a first project.

73,
Todd
N9MWB

------------------------------

Date: Fri, 4 Nov 1994 07:50:15 +8
From: [e-mail] (David L. Bergart)

References<[e-mail]> <3, <[e-mail]>
Subject: Re: THE LITTLE RAZOR BLADE RADIO (UPDATE)

 >Sure you could make some lead sulfide by the method you describe... but,
 >would it be galena! Would it work as a detector ? ... did you try it ?

Yup, sure does. I must admit, though, that after I went to the trouble of
making galena, and gloating about what a good boy I was, I went back to using
store-bought diodes---much easier to use, and I am REAL lazy.

David


____D__a__v__i__d_____B__e__r__g__a__r__t___________________________________
                                              [e-mail]

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End of Ham-Homebrew Digest V94 #326
******************************