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History and Evolution
The "Tiny Tornado" is a tiny HF CW transceiver, with a standard two transistor transmitter. It's a Colpitts oscillator, left running, and a keyed power amplifier. There is no
external mixer used to feed the audio amplifier. Instead, the mixing is done at the final amplifier itself with the resulting audio taken off the emitter.
The mixer-oscillator has been around for a long
time. This concept was used in early tube designs.
This kit is based on a modified Pixie circuit with a much improved
layout and is complete with a detailed assembly manual
and operating instructions.
A total of 207 of the Tiny-Tornado kits were
produced.
TINY-TORNADO REV1a (PROTOTYPE) This board is based on a Pixie 2 style circuit which traces it's history
back to the Micro-80 transceiver by Oleg Borodin, RV3GM. This board is
based very closely on the board that was laid out by Doug Hendricks
for the original Pixie 2. There was a resistor left off the
original Pixie 2 board and this was essentially a fix. I had a
few of these boards printed so I could build myself a Pixie transceiver with a
really nice PCB. These
are photographs of the prototype boards that I had printed. Three (3) of these
kits were produced.
"Tiny-Tornado
Prototype Rev. 1a #1" PCB (Top)
"Tiny-Tornado
Prototype Rev. 1a #1" PCB (Bottom)
TINY-TORNADO REV1b
At the SAME time I did the REV1a
boards, I also had three of these REV1b boards printed.
Honestly, I made so many changes to the layout and additional of so
many "mods" I didn't know for sure if these would work until
I built one. This transceiver was called the "QRPp-I Transceiver". It later became
known as the "QRPp-I Mini-Transceiver" and then on to become
the "Tiny-Tornado" as we know it today. This was an improved layout
design. This also included a provision on the board for a TX/RX
offset which could be used as a type of RIT/XIT. The board measures only 30mm x
43mm!
Three (3) of these kits produced.
TINY-TORNADO REV1b (QRPp-I Transceiver™)
TINY-TORNADO REV2a
The origin of the name "Tiny-Tornado"
is a bit strange. Besides amateur radio, another one of my hobbies is
storm chasing / spotting. I had a dream one night of of being at a
hamfest during a thunderstorm and selling a tiny transceiver kit out of the
back of my truck. The tiny transceiver kit was called the
"Tiny-Tornado". After that, I decided I should produce a few
more kits and sell them. The REV2a was the first of these that actually
had the name "Tiny-Tornado" printed on the PCB.
This version also had improved layout and
spacing over the previous versions. This is also the version where the ground plane was
added which was a significant difference and improvement over previous
designs.
Twelve (12) of these kits produced.
TINY-TORNADO REV2a PCB
TINY-TORNADO
REV2a (TT-40™)
(Click Photos for Larger Image)
TINY-TORNADO REV2b Improved layout and
spacing. Also, an improved output filter was added as well as a
simple audio filter and a reverse polarity protection diode. This is
also the first time the kit was offered for 20, 30, 40, and 80 meter
bands. However, these REV2b boards were only sent to those who
ordered a single 40 meter kit because of two missing holes required for
the other bands. See the REV2c version. The board measures only 30mm x
43mm! This was also the first of my
transceiver kits to have "CQ" in Morse Code printed on the PCB. Nine (9) of
these kits produced.
TINY-TORNADO REV2c
The REV2b and REV2c boards
were very similar and even included some new features such as reverse
polarity protection, an improved output filter, and the ability
to add an external audio preamplifier stage or filter before the audio
amplifier. Some parts may vary from those shown in these photos.
Bands other than 40 meters
require additional capacitors in parallel to achieve the appropriate
values. Two additional holes were added to this version of the
board. That is the only change from the REV2b PCB. The board measures only 30mm x
43mm!
Fifty-four (54) of these kits
were produced.
TINY-TORNADO REV2c PCB
In the above
photo, the ground plane on the
back of the board shows through as the darker area. Notice the board is
a double-sided plated-through hole design. 
TINY-TORNADO REV2a (TT-40™)
(Ground plane on the back side of the board!)
TINY-TORNADO REV2d Very similar to the REV2c
boards with the addition of another pair of holes to experiment with
converting the LM386 into an active audio filter. The board measures only 30mm x
43mm! One Hundred Twenty-Six (126) of
these kits were produced. February
through March 2003 - Another Thirty (30) Tiny-Tornado REV2d boards were
printed and sold. This time, there was no complete kit available... but
the Tiny-Tornado lives on! 
TINY-TORNADO REV2d (TT-xx™)
(Shown without the Low Pass Filter and XTAL installed. The quarter is not
included with the kit and is shown here for a size comparison.)
TINY-TORNADO REV2e March
2003 - A total of Six (6) Rev2e boards were printed. The only change was
the ground plane was moved to the top of the board. It it unknown at
this time if more will be produced.
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