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What's
Happening:
Recent Stuff:
5/31/10
I received an email from Marcus Hansen, VE7CA that he has a new domain for his web site. Marcus is the designer of the acclaimed homebrew HBR2000 160 - 10 meter transceiver. You can access Markus' web site from the Links section (quick jump from the menu to the left).
4/17/10
I'v added a link to Todd, VE7VPO's QRP/SWL Homebuilder site. I've watched Todd's site develop over the years, and it is a great site for tutorial articles and experimentation. You can access Todd's web site from the Links section (quick jump from the menu to the left).
2/9/10
I just added a new link to Hans, SA7AUY's web site. If you are a Heathkit fan, you've got to see his photos of ham equipment and test gear. I told Hans that he has inspired me to take some photos of my boatanchors and put them on my site.
2/2/10
I've changed the look of the site quite a bit and removed some outdated content.
12/16/09
I added some new files to the
Tempo 2020 page restoration page in the Technical Solutions
section of the site. Included are a PDF file of the procedure to
remove and replace Preselector sprockets and chains with new
parts obtained from a vendor, and a zip file of 19 photos of the
process. Also, see some general info on the 2020 (made by Uniden,
sold by Henry Radio) in the 8/18/09 log entry.
8/18/09
I updated some stuff here on the
home page, mainly in the "Ongoing Projects" section. I've also
added some modifications to the 40 Meter Superhet receiver on its
page.
For months, I have been busy working on a couple of Tempo 2020
transceivers ("BoatAnchors" - they may not be the oldest of
vintage rigs, but they certainly pass the weight criterion of the
nickname.) I kept a detailed log of every step in the work, as I
unfortunately can't trust my memory. As of the end of July 2009 I
finished the work and tested them on the air during the IARU
contest on 20 meters. I was able to work Ontario, Canada and
Aruba within a 5 minute period of on-the-air operation. I had to
use my crummy homebrew G5RV that has one end sloping down to
about 7'...tree limbs keep falling on it and messing it up. The
2020 is a very interesting rig, one that somehow escaped my
notice back in its production run. Some highlights of the Tempo 2020: built in AC
and DC power supplies; two 6146Bs in the final, with Zener regulation of the screen voltage; individual LSB, USB and CW crystal filters; 100 kHz-range
VFO, with switched heterodyned and PLLed band segment ranges;
conservative plate voltage at 600V; and a separate CW carrier
oscillator. I've developed some repair instructions for a couple
of frequent issues with these rigs - replacing the sprockets for
the preselector and bandswitch drive trains, and replacement of
the PA compartment bandswitch shaft coupler. Both of these are
something of a challenge. In doing the final checkout of the
rigs, I used my homebrew Log Power Meter and -20dBm test source
to check out the receiver and calibrate the S-meter readings.
Click on the Tempo 2020 restoration item on the menu item for
Technical Solutions for more details.
Here are some projects that I have
completed:
A
Log Power Meter, designed by Wes Hayward,
W7ZOI and Bob Larkin, W7PUA (June 2001 QST; article available
as a Members Only download). See my step-by-step photos
and description here.
This device allows direct measurement
of signals of over 20 mW (+13 dBm) to less than 0.1 nW (-70
dBm). It
consists of an inexpensive Analog Devices logarithmic amplifier
IC, a common 78L05 voltage regulator, an LM358 op amp, a few
common resistors and capacitors, two RF connectors, a SPST
switch, a $12.99 Radio Shack panel meter, and a die-cast or
standard Radio Shack aluminum box as the enclosure. A DVM may
be connected through a feed-through capacitor when greater
resolution is required. Using this device, stage gains can be
directly measured in homebrew transmitters and receivers in the
development phase. Also, by attaching a signal generator and a
return loss bridge (a simple homebrew passive device), RF
filters can be measured for insertion loss and even filter
adjustment can be done. An auxiliary 40-dB power tap attenuator
described in the article extends the measurement level to +50
dBm, which is 100 Watts. Wes suggested that this would be a
very valuable instrument for me to use in homebrewing and
experimentation prior to building his spectrum analyzer. Wes
has updated information on his web
site.
A Step
Attenuator is one of the most useful test units you can have in
the shack. Combined with a signal generator and a Log Power
Meter or oscilloscope, you can make very accurate readings of
things like stage gain in a receiver or transmitter. I built
mine just a bit different than some others that I've seen.
Check it
out.
40 Meter
Superhet with Digital Readout I built this
receiver for my grandson, who has an interest in all things electronic. Here's the
link to the
project.
The ELSIE L-C Meter.
the ELSIE LC meter is an accurate, simple device for measuring inductance and capacitance. The ELSIE was designed by Joe Everhart, N2CX and Steve
Weber, KD1JV. At one time it was kitted by the American QRP
Club, but it's no longer in production. Although it can
certainly be built using one of the free-form methods,
including Ugly and Manhattan construction, I made a board in EAGLE Cad. Instead of the possibly more
familiar PIC microcontrollers, the ELSIE uses Steve's favorite,
the Atmel family of microcontrollers. So, along with the ELSIE, I had to build
a device programmer and locate software to "flash" the chip, an
AT90S2313. My ELSIE is finished and working fine. I
recently replaced the key capacitor that ELSIE uses for
internal calibration with a 1% one (was 2%), and it's even more
accurate. I use it a LOT. Here's the finished
ELSIE.
A
30 meter transceiver for Straight Key
Night.I built this rig for operation on Straight Key Night a few years ago. Click on the link and see the work
as it progressed through the building period. This rig uses a modified Vectronics
VXO transmitter unit, and the receiver section from the SW-40+ designed by K1SWL and described in the Elmer 101 web project.
A
-20dBm 20 meter test source, designed by Jim
Kortge, K8IQY. I'm not providing any build photos, etc., on
this one, because it did it just like Jim did, down to the 1/4"
copper shielding tape. Check it out on the k8iqy.com web site.
UPDATE - To extend the range for MDS determination and S-meter
calibration, I built a stand-alone 40 dB attenuator to use with
the test source and step
attenuator.
"The
Challenger 40", a homebrewed 40 meter
transmitter based on the Wes Hayward,
W7ZOI-designed transmitter in Chapter 1 of "Experimental
Methods in RF Design".
A Sealed Lead Acid Battery Charger
of a rather unique design, by Bob, AA4PB. Hmmm...it just struck
me that "Pb" is the periodic table abbreviation for Lead. The
article appeared in the May 2001 issue of QST. Unlike simpler chargers, AA4PB's design does not maintain a fixed-voltage, trickle current float on the batteries. It applies charging cycles only when the voltage is below a level set by a voltage comparator. LEDs indicate when the charging cycle is on (green) or off (red). Even in a fully discharged state, the battery is brought up to full voltage by cycling the charge current. It works very
well, and it's a nice project. I keep my stock of 7 AH gel
cells charged with it. Check out my finished build
photos.
A
home-brewed circuit board version of the Precision VXO and Crystal
Test Fixture designed by Jim Kortge, K8IQY. If you
homebrew superhets or SSB transmitters with crystal filters,
you really need one of these test sets, or one of the other
designs out there, for obtaining crystal parameters. Jim's
design provides very comprehensive
testing.
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Here are
some projects that I have in
progress:
I'm working on an HF CW/SSB transceiver based on Experimental Methods on RF Design
elements. First off the drawing board was a cascode-JFET IF
strip, with IF-derived AGC. I originally did the board (see the
board layout in link) using Eagle CAD Lite, but I put that
aside when Wes, W7ZOI made some changes. I ordered a new board
designed by Roger Hayward, KA7EXM, the Hybride Cascode IF system. It is not only an improved
design, it is quite a bit smaller than my homebrew board. The
receiver front end, the VFO and the transmitter and PA all come
from examples and projects in EMRFD.
A 20 meter SSB
transceiver based on Ron Taylor, G4GXO's Belthorn
SSB IF Module, with input from Pete Juliano, N6QW (formerly
W6JFR) and Zack Lau, W1VT. With this particular SSB-only rig I
plan to shoot for about 40 watts PEP output. I have mobile and portable operation
in mind for this unit. I also intend to use this rig as a 20m IF rig to use with my Ten-Tec 6m transverter.
One of the nice things about the Belthorn SSB IF
module is that allows for lots of possibilities, while maintaining
a solid basic transceiver design at the heart of the rig. The SSB IF module uses SBL-1 diode ring mixers and an LM1350 IF stage.
Pete has built a
Belthorn-based transceiver for 20 meters, along with several
other rigs of various designs.
I'm working on a multiband push-pull power amplifier to give a boost to low power transmitters. The basic design is the WA2EBY amplifier from QST
and the Handbook, but I've decided on an alternative to the
bandswitched filter board. I'm using a design based on the
CDG2000 by G3OCQ, modified for Omron G5V-1 relays that I was
able to get for $.99 each from the Electronic Goldmine, and
I've added 30 meters. I worked out the values for the filter
components for 30 meters following the standard CDG2000
topology using the excellent (and free) RFSim99
program. Rather than attaching the switch wafer to the filter
board as in the basic WA2EBY design, using the eight SPDT
relays allows for convenient placement of the bandswitch
anywhere on the front panel of the amplifier enclosure. I'll be
using some planned rigs with various low outlet levels, so attenuators
will be used with the amp. I've got the relays and silver mica
caps mounted on the filter board. Output power will be limited
to the capability of the relays.
The KD1JV-designed MS-DDS-60 DDS VFO
controller. Used in conjunction with my
AD9850-based DDS Daughter Card, the combined unit will be
capable of direct digital synthesis of frequencies up to 30 MHz
(an AD9854 Daughter card goes up to 60 MHz). Steve, KD1JV's
controller, a kit (which is no longer in production), adds
several important control features, including logic output for
band-switching of filters, etc., and stored frequencies, CW
enhancements, and others. My most likely application for this
may be as a high-resolution signal generator; I've done so much
design, planning and parts-gathering for the transceivers I'm working on that I think it's better to go with HFO
crystal-mixed LO's on those.
In addition I've got many (too
many?) projects that receive attention from time to time. These
are just a few: I started on the 2N2/40 in 2005 or 2006, I
think, and as of August 2009, I have added the switching
section and RX RF amp to the board layout. Now the VFO doesn't
feel so lonely sitting there in the middle of the board by
itself. Also, I have a single band amplifier board etched,
based on a W1FB design from the January '96 CQ magazine.
I built it mainly to experiment with various drivers and PA transistors. I have some
some inexpensive 2SC5739 transistors, some IRF510 MOSFETs and some Mitsubishi RF MOSFETs to see what I can get out of them on 40 meters at 13.6
volts. I'm also revitalizing my formerly-old standby HW-101. I've got a Zener diode string and shunt transistor screen regulator designed by Allison, KB1GMX, going in that rig as soon as I get it otherwise fully functional again. I checked out the design using SIMetrix SPICE, and it looks like it's a go. (Thanks to my friend Harold, KE6TI for introducing me to this very fine free SPICE modeling program.)
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Making
Twelfth-wave Matching Sections for Coaxial Feed
Lines
Coaxial
feedlines can be easily matched to each other; for example you
can use low-loss 75 ohm RG-6U to feed a dipole, and then bring
50 ohm RG-58U into the transmitter, matched at 1:1 SWR. Based
on an article on Darrel Emerson, AA7FV’s website at
http://ourworld.compuserve.com/homepages/demerson/twelfth.htm,
I have developed a method for making connectors to join the
coaxial matching sections for the two main feed lines, and I
have created a spreadsheet for performing the calculations for
the length of the two matching sections required. Here's the
solution.
Download an Excel spreadsheet to calculate 12th-wave
matching sections here
on this
website.
Making Printed Circuit
Boards
Here's the process I
use to make printed circuit
boards.
Restoration
work on the Tempo 2020
transceiver.
I've been
working on restoring a couple of Tempo 2020 '70s vintage transceivers.
Here
are some procedures (in downloadable PDF format) that I've
developed for a couple of particulary difficult
issues.
The DOS under
Windows XP
problem:
If you are
having problem running legacy DOS programs in Windows XP or Vista,
here's a solution: DOSBox, a free and still under development
virtual x86 environment that runs on top of Windows XP
(DosBox.sourceforge.net). Many DOS programs that ran in a DOS
window under previous versions of Windows run full screen in
XP, and there is no way to do a screen capture or printscreen.
DOSBox provides its own environment such that the programs run
in the DOSBox window. The screen resolution is best if you set
it at 800 x 600. Note that since DOSBox is a virtual
environment, it runs with a defined memory space, so you may
have to temporarily close down other running XP applications.
Note: I used version 0.63 when I was evaluating DOSBox.
The next version, Version 0.65 gave me problems in running the
programs. This was corrected in Version
0.70. Update: I downloaded Version 0.78 in March 2010, and it works with Vista.
I was
pleased to be able to provide WES Hayward, W7ZOI and Kirt
Blattenberger of RF Cafe with this solution to their
long-standing problem, that of getting certain of their older
DOS software to run effectively under Windows
XP.
See Wes's
web site and RF Cafe (link
below) below for a detailed explanation with examples on how
DOSBox is used with legacy programs under
XP.
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Here are some
must-visit links to very fine technical information, used with
permission:
Wes Hayward, W7ZOI is the author of
many published articles and books on electrical engineering and
amateur radio. His designs have inspired thousands of hams over
the years to build their own equipment. His book, "Experimental
Methods in RF Design", published by the ARRL, is truly one of
the most influential works for amateur
radio. Visit Wes' web site for updated info on his projects.
Markus
Hansen, VE7CA documents his outstanding homebrew
creation, the HBR2000 160 to 10 meter
transceiver on his pages. Markus's remarkable design was published in
the March 2006 issue of QST, and his further work continues
with the rig, with details on his site. It is a beacon in the
night to those of us who design and build our own equipment
without the benefit of a degree in
engineering.
Ian Purdie,
VK2TIP's excellent tutorials
on basic electronics and circuit
design.
One of the most interesting sites I've followed for several years is Todd Gale, VE7BPO's QRP/SWL Homebuilder site. Todd has a lot of tutorial and construction articles with a focus on experimentation. Click on this link for some great info and ideas.
For some
top-notch information on portable HF antenna design and many other homebrew
topics visit the
web site of Phil Salas, AD5X.
If you
haven't yet built a QRP rig for 30 meters, check out Jim
Kortge, K8IQY's "Manhattan Madness" project page and the
2N2/30.
It's
evolutionary!
Learn how
to build top-notch enclosures for your QRP rigs
using ABS plastic at Bill Jones, KD7S's
Site.
Morse keys
and homebrewing...nice, if you have a shop full of power tools
and are an accomplished machinist, right? Well, take a look at
Richard Meiss, WB9BLU's work, and recalibrate your thinking!
This site gives a detailed
explanation, with photos, on building your own first-rate
straight key. Here is a gallery
of some of Richard's finest work, and here he provides some insight
into his process and thinking, as well as more examples.
Richard's keys were on display at Four Days in May at the Dayton Hamfest in
2007.
RF Cafe is a unique portal for RF
and microwave engineering resources. There you will find a vast
collection of original content with definitions, equations,
references and conversions that cover electrical, mechanical,
physical, chemical and mathematical fields. Many interactive
calculators are available for everything from filters to
voltage dividers. In addition, you will find extensive links to
other websites for vendor parts, application notes, test notes,
amateur radio information, technical magazines and books,
patent and communications standards, and much more. Kirt
Blattenberger does a fantastic job in maintaining this site. If
you are designing a receiving system, check out his RF Cascade
Workbook for Excel, and try out RF Workbench. Kirt has posted
some updated (December, 2005) information regarding how to use
the latter while running under Windows
XP.
Rich
Herzer, AF2CW's site. Rich
recently contacted me regarding the new Straight Key Century
Club details, and I got his permission to link to his site.
Seems like everybody has a "Mega-Links" site on their page, but
Rich has one that has my favorite topics...CW and Classic
Radios, along with links to other popular Links sites, such as
AC6V.
Lloyd
Butler, VK5BR's web site
contains a wealth of articles on theory and technical practices
that he has written for the Australian journal "Amateur Radio",
as well as several interesting technical projects and
experiments. Be sure to check out his heterodyne sweep
generator and other homebrew test equipment...no
microcontrollers
required!.
Hans
Gatu, SA7AUY's great Heathkit site. Hans has some of the best Heathkit photos I've seen on the web. One of his other interests is photography, and it really shows in his high-resolution photos of his equipment. Here's an example: If you are considering buying a DX-35 for getting on AM, and you want to see what one looks like in perfect condition, look at the photos of Hans' DX-35. Hans also has a nice set of Heath catalog covers through the years. This is a "must see" site for Heathkit aficianados.
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This web
site was sparsely created using NoteTab Light, and is now
maintained using PSPad (and FileZilla for FTP.)
Web site links are with the expressed permission of the
owners.
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