QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/files/qrp/archives/current.txt/text0003.txt

Text File | 1994-11-27 | 12.5 KB | 266 lines

I have seen this described before by the fellow who described it in one
of the arrl antenna compendiums. The sleeve method works for a t tuner
although it can get very, very warm when running somehting more than qrp!
The design looks intriguing but EXPENSIVE even with flea market prices
for roller inductors.........how to keep them in synch?
I have been interested in building one......has anybody actually done this?
Performance and technical building tips appreciated.

****************************************************************************
Dr. Rick Zabrodski BSc, MD, CCFP(E)       *            VE6GK "glider king"
EMAIL:  [e-mail]          *            "M.D. on weekdays"
Packet: VE6GK@VE6YYC.#cgy.ab.can.na       *          "Solar powered aviator
Phone: [phone]   Fax: [phone]     *               on weekends!"
****************************************************************************
                                    _____
                                      |
          \__________________________/ \__________________________/
                                     \_/


On Sat, 2 Jul 1994 [e-mail] wrote:

> On 07-01-94  [e-mail] wrote to  [e-mail]:
>
>  > P.S. Can anyone recommend the best articles / texts on general, very
>  > basic antenna tuner circuits?  I would like to know about the basic 5
>  > or 6 designs, and elementary theory of operation.  I have the ARRL
>  > Antenna book, which is not what I want.
>
> QRP Classics gives us "A Simple Resonant ATU" (I made a cobbled-up balanced
> version), and "A QRP Transmatch for Balanced Lines" (a variant of one of my
> favorite designs)
>
> My favorite:  Feb. 1990 QST, page 28ff details "A *Balanced* Balanced Antenna
> Tuner".
>
> Basic premise:  Most commercial tuners put a 4:1 toroid
> transmission-line transformer on the output and call that suitable for
> balanced lines.  This is nuts, because they don't perform under
> reactive, unmatched conditions (the usual situation in tuned lines) and
> aren't balanced to give equal *current* in both legs under all
> circumstances. You need equal *currents*, not *voltages*, in a balanced
> line to keep it from radiating.
>
> Solution:  put your balun on the INPUT -- a choke balun of coiled coax
> is cheap, ugly, but very effective.  Can also use ferrite sleeve balun,
> like the W2AU. And, use a balanced L network, where you split the
> series elements in both legs of the balanced line.
>
> My version:
>
>                        ____UUUUUUU_______________<
>                       / Roller inductor 1  |
>                      /                     |
>     Coax choke balun<             Var. cap.=      Bal. ant.
>   20' RG58           \                     |
>     on 5" form        \_ __UUUUUUU_________|____ <
>                         Roller inductor 2
>                         (mechanically linked to #1)
>
> Little RF in shack since I put this in!
>
> Your balun could also be a ferrite sleeve balun, or a 1:1 CONVENTIONAL
> transformer of adequate power rating.
>
> * John Seboldt...Mpls, MN...As a ham, K0JD...as a human...well,... *
> |                     [e-mail]                         |
> *      J.S. Bach of Borg:  "Your style will be assimilated."       *
>
>  -> Alice4Mac 2.3 E QWK Eval:05Mar94
>

From [e-mail]  Mon Jul  4 15:06:17 1994
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    id AA773340205 Mon, 04 Jul 94 09:43:25 PST
Date: Mon, 04 Jul 94 09:43:25 PST
From: [e-mail]
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To: [e-mail]
Subject: Lucking out at the surplus store
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I happened to be rooting through the back room at RP Electronics
in Vancouver Saturday, and happened across some wonderful
goodies...

They had a box of bags of parts (OEM quantities), most of which
were things I couldn't use in such quantities, like 10 uF
electrolytics. No .1 or .01 uF bypass capacitors. What I *did*
find, though, was a box full of zener and other diodes, 7808
voltage regulators, IF can transformers (yellow, green and white
cores), miscellaneous TO-92 transistors, and what may be some
varactor diodes. Another box was full of crystals - about a dozen
each of 2.16MHz, 2.25MHz, and a handful of other values. I also
found a bag of *two hundred* 3.6864MHz crystals. Thirteen bucks
for the whole works.

Needless to say, I dug out all my W7ZOI references on crystal
filter construction that night...time to warm up the frequency
counter!

BTW - a question for our U.K. friends - are there any events
happening in the U.K. the first week of September that a visiting
ham would want to know about? I'll be based in the south east,
but wouldn't mind an excuse to travel.

73 from Burnaby,
laura VE7LDH who needs to get her paperwork to SSL *fast*

From [e-mail]  Mon Jul  4 15:41:41 1994
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From: [e-mail] (Mike Czuhajewski)
To: [e-mail]
Subject: QRP library comments
Date: Mon, 04 Jul 94 15:21:17 EST5EDT
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Some additional comments on some of the books on the recent QRPers
library list put out by Jim Johns, KA0IQT--

>Ferromagnetic Core Design & Application Handbook, M. F. Doug DeMaw,
>Prentice Hall 1981, 256 pages Hard Cover. Core and inductor data,
>information and applications.

       Comment--book now out of print for a while.  I saw a copy once
but did not want to pay the $26 for it--I thought it was too
expensive for the contents, priced more for the college textbook or
professional engineering crowd, not for the homebrewer or amateur.
(While it may have over 200 pages, it's not a large book--it was
something like 6 X 9".) Final price before it went out of print
several years later was somewhere over $50!  Doug DeMaw said in CQ
magazine a year or two ago that he had given permission to Amidon to
reprint it. In a private letter, he said he had not heard from them
since he gave permission.  I wrote to Amidon last year, asking about
it, but never received a reply so it may be gone for good, or waiting
for someone else to decide to republish it.

>History of QRP in the U.S. 1924-1960, Adrian Weiss W0RSP, Milliwatt
>Books 1987, 199 pages Soft Cover.  One man's view of the history of
>QRP.

     Comments--derived mainly from the pages of old QSTs, I believe,
this is a truly fascinating book on the subject.  Now if we could
just get Ade (or someone else) to write a history of QRP from 1960 to
present...  Availability unknown, but may still be available from
Ade.

>Introduction to Radio Frequency Design, Wes Hayward, Prentice-Hall
>1982, 383 pages Hard Cover.  Good technical text but with only a few
>practical circuits.

     Comments--for the technically inclined homebrewer, this is a
good book by one of the masters  (he also co-authored the QRPers
technical bible, Solid State Design for the Radio Amateur).  Current
availability unknown.  Probably priced for the textbook/professional
market.  This one is high on my list of "books that are good enough
to risk stealing from someones library."

>The Joy of QRP: Strategy for Success, Adrian Weiss, Milliwatt Books
>1984, 151 pages Soft Cover. Chatty overview of QRP, oriented more to
>operation than technical, but does include several projects.

     Comments:  Out of print for quite a few years--it took about 2
years for it to sell out, and is considered by many to be a classic.
Requests for a copy appear from time to time in the QRP journals and
on the packet radio BBS system.  Some QRPers who do have a copy keep
it under lock and key when other QRPers visit them, and only loan it
out if the recipient posts his home and car as collateral.  (Some of
the references to rigs are quite dated; most of the tube type rigs
mentioned are probably virtually unobtainable.  Most of the book is
filled with a great deal of good QRP info.) Note--Ade gets extra
points for correctly spelling my last name in both of his books.  Ade
himself recently put out a message on the QRP forum (June 1994)
saying that he has no objections to anyone copying it for a friend.

>QRP Classics, Bob Schetgen KU7G editor, ARRL 1990, 274 pages Soft
>Cover. Reprints of QRP articles from QST.  Good compendium.  Missing
>some  "classic" designs (The original W7EL design for one).

     Comments: As I recall, this received some mixed reviews in the
QRP press.  In the second printing, the W7EL rig was inserted with
surgical precision; they sliced out two articles and moved them to
the rear of the book, and the W7EL fit right in the open spot without
even disturbing the page numbering.

>The HW-8 Handbook 1st edition, compiled and edited by Michael Bryce
>WB8VGE, 1991, 56 pages Soft Cover. Contains tips and mods for the
>Heathkit HW-7, HW-8 and HW-9 QRP transceivers.  Reprinted several
>times, this classic is still in great demand.

     Comments:  The first two incarnations were known as the Hotwater
Handbook; originally done by W5QJM, updated by WB8VGE.  The third
incarnation was changed to "HW-8 Handbook" due to confusion over the
title "Hotwater Handbook;" many people thought it also referred to
the Heath "Hotwater" series, such as HW-101, HW-12/22/32, and many
others, all of which were often called "HotWater" rigs.  Third
incarnation sold out fairly fast, recently reprinted by WB8VGE.  Does
not contain any new info since the first printing, although some has
appeared in various places.

>RF Circuit Design, Chris Bowick, Howard Sams & Co. 1982, 176 pages
>Soft Cover. This book, once out of print, offers insight into RF
>design including the use of Smith Charts.  Not for the beginner it
>offers valuable information for the intermediate to advanced
>designer.

     Comments:  I reviewed this in the QRP Quarterly recently.
Definitely not for the beginner, definitely of interest to the more
technically inclined ham.  Once again available; two chapters were
excerpted in Ham Radio magazine quite a few years ago.

Another good book not on Jims list:  The Joy of Electronics by
Horowitz and Hill.  Priced somewhere in the $70 range, and well worth
it--heavy, lots of pages.  I have a copy on my desk at work, provided
by the company,  (Also available:  student workbook; I've seen it but
didn't have the chance to open it; in the $25 class, I think.)  Lots
of good info on a wide variety of electronics topics, usable by the
relative beginner as well as more advanced.  Not heavy into math.
Get the second printing if possible--updated from the first one.  Has
sold over 125,000 copies and widely held in high regard.  Readable,
easy to understand; includes examples of what NOT to do.

73 and Queue Our Pea DE WA8MCQ
--
Mike Czuhajewski, user of the UniBoard System @ wb3ffv.ampr.org
E-Mail: [e-mail]
The WB3FFV Amateur Radio BBS - Located in Baltimore, Maryland USA
Supporting the Amateur Radio Hobby, and TCP/IP InterNetworking

From [e-mail]  Mon Jul  4 15:41:43 1994
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Date: Mon, 4 Jul 94 14:40:57 -0500
From: [e-mail] (Chuck Adams)
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To: [e-mail]
Subject: Re:  St. Louis & Okla. QRP Club Address??
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OK QRP Group (OKlahoma)
Don Kelly, Editor
703 West 8th St.
Edmond, OK  73003

dit dit
Chuck Adams  K5FO  CP-60
[e-mail]