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2000, Red Hot Radio – Unauthorized Copying or Publication Prohibited
10uF & 100uF Capacitors
Next, locate the 10uF and 100uF capacitors, items 8 &
9. Solder them in place on the PCB paying careful
attention to the polarization. The black end of the
capacitor is negative (-) and should be at the opposite
end from the + symbol on the PCB legend.
TX Output Transformer (T1)
The output transformer is bifilar wound on the toroid. It
is quite easily done. Take the toroid and the two pieces
of red and green wire.
parallel and wind 6 turns on the toroid, counting one turn
each time you go through the toroid. When you finish,
prepare the ends of the wire by trimming them about 1
inch long at first. Then burn the insulation off to the
edge of the core, use a piece of sandpaper to get all of
the insulation off and make sure that you have bright
copper wire showing. Tin each of the four leads. Now,
trim each of the leads so that they are ¼" long. Solder
the toroid on the pads, making sure that you solder the
red leads to pads 1 & 2 and the green leads to pads 3 &
4. You must do this correctly.
Crystals
The crystals are through hole parts. Place them in the
position indicated and solder them in. The cases must
be grounded and we have provided a place to do this.
Find a cutoff resistor lead (sorry, but there are no leaded
resistors here, but you should have one around). Solder
it in the hole next to the crystal. Bend the lead over the
crystal and solder it to the case of the crystal. Do this
quickly so as to not kill the crystal!!
Pots
Next, solder in the pots. Make sure that they are fully
seated to the board. This is important when you mount
your SMK-1 in its case (You did order the case and
connectors from the NJ QRP Club didn't you??).
Finally, solder in the two trim caps. They are the little
square orange devices from Bag #2. When you solder
them in, make sure that you orient them exactly as
shown on the silkscreen of the board.
Wiring Up
Wiring the connectors is simple.
stranded hookup wire and connect the speaker jack, key
jack, power jack and antenna jack of your choice to the
back of the board.
Hold the two pieces of wire
Use small gauge
Testing
Now it is time to test your efforts. Attach a dummy load.
Then apply 12 volts. Check for smoke, and hopefully
there won't be any!! Replace the dummy load with an
antenna. We will start with the receiver section. Plug in
a set of headphones. Peak TC1 first to make sure that
you have 2 peaks. Go for highest noise level or signal.
Next peak TC2 for loudest signal.
transmitter, and that is the easy part. Plug in a key, and
transmit. Monitor on another receiver to make sure that
you are putting out power.
If you have problems, go to qrp-l, and post your problem.
There are literally thousands of fellow qrpers there who
will be more than happy to help with your problem.
Operation
Test units of the SMK-1 have tuned from about 7.035 to
7.039.7 on the receiver, and 7.0375 to 7.039 on the
transmitter. Thus the transmitter is the limiting factor on
making contacts. Use a transceiver to verify which side
of your signal that you want to tune the receiver to. You
will soon learn that a dc receiver has two sidebands, and
that you want to be on the correct one to make contacts.
Verify the correct sideband on a transceiver, and then
note which way that you tune the receiver in relation to
the tone, (whether it goes up or down in pitch as you
tune). Don't worry, you will soon get the hang of it. If
you have questions, again, get on qrp-l, someone will be
there to assist you.
Again, the purpose of this kit was to assist you in
learning how to work with surface mount parts.
believe that it succeeds, and for a very modest cost.
The transceiver does work, and it is capable of making
contacts. It is not an ICOM 706 by any means though.
We will be coming out with a full featured single band
surface mount kit later, this kit is just for training and we
hope that you have enjoyed it.
5
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