AT Sprint 2 Transceiver - Built by AL7FS

Jim Larsen - AL7FS AK/QRP #003





A few years ago, I tried building the Norcal SMK-1 SMD kit. It was a simple kit and got me started. I had always wanted to see if I could handle building a more complex Surface Mount Device (SMD) kit. KD1JV, Steve Weber, provided the perfect opportunity with his limited run AT Sprint 2 (ATS-2) Transceiver Kit. I just had to try it. Will it be fun or frustrating? It was fun!!

I have been involved with QRP since about 1970. Having built many of the kits that have been available over the years including the Elecraft K2 transceiver, I just felt I could handle this SMD type of kit. Knowing this I dived into the KD1JV ATS-2..

The Simple Tools

In order to work with Surface Mount parts I knew that I would need to have at least some of the right tools. These parts are very small and can flick away into the ether, never to be seen again. First off was a cake pan; I bought a new, shiny one. Also, I needed a few small little trays that would fit into the cake pan with my project. I found some nice white plastic ones that show up the tiny parts quite nicely. As luck would have it, my Weller WCTCPT soldering pencil had a nice sharp, small tip on it and should work for this type work. I wear bifocals on my bifocals so that I can see the parts. Others use a large lighted magnifier. Others use a headset. You will have to find what works for you.

Past articles have demonstrated how to make a SMD Doofus to hold the parts in place while one does the soldering. There are several ways to do this. A good reference on this is found at (http://www.qsl.net/n5ib/surface_mount/ ). Of course I had to build my own and with the help of KL7CC, Jim Wiley, our version looked a bit different from the ones in the reference. Of course you don't need the fancy toothpick device on the end. Just bend down the coat hanger and file the tip the way you like. File down two or three for different uses such as one with a notch for doing diodes.



The pan and trays and board and doofus fit into the scheme like this:


Now that I had the simple tools, it was time to get to work. Being ever so careful with the tiny parts, I began to dig into the kit. Take a look at what you are dealing with for parts size.

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Getting into the Project

As I began I was struck by how small these parts were. They were not all the big 1206 size parts. There were going to be some of the 0805 sizes, too. Thankfully, there were none of the 0603 sizes although by the end of the kit, I think I could have handled a few of them. Practice does help.

Place the part, put the doofus on top, use the solder provided or the smallest you can possibly buy, and go for it. It is actually pretty painless. When I built the SMK-1 kit, I first tinned a tiny bit of solder on one of the pads. I tried this again for this kit and did not like the results, at least for me. This method seemed to make the parts move off center and look bad. My three fishing-weight doofus held the part firmly enough that I could just go for it with my 700 degree soldering tip. This is what it looked like doing the small capacitors.



You probably notice that the ICs are already done. That was a bit of a challenge but if you have solder braid on hand, then go for it. If the solder bridges between pins, and it probably will, on the tiniest of ICs, then just lay on the braid and lift off a bit of the excess. Works very well. I had no trouble with most of the ICs...just the one IC that was really close spaced (up and left of the toothpick) and even then I only bridged one set of pins.

The project proceeded piece by piece. I tried to stay focused on each part and not feel overwhelmed by the tasks ahead. One at a time does the trick.


Finally, the main board was done. It looked pretty nice and I was excited to move on to the small boards for each band. Now came the time of the toroid winding but all the parts were full size now.


Winding toroids is not really a big deal although when there are as many as this radio had, I must confess my fingers got a bit sore. The 80 meter toroids just about killed me. It felt like 300 turns but of course it wasn't that many. Remember, every time the wire goes through the donut it counts as one turn. Instructions were well done in the manual and if you do a Google search on "how to wind toroids" you will find plenty of information.


The 20 meter board was soon done and it sure looked nice beside the main board.

The rig will operate on four bands from 80 through 20 meters and the band modules plug into the back of the board.


And when they are all done they look like this.



The boards were soon mounted in the AT Sprint 2 case; I had some trouble with mine. The mounting holes were drilled such that the jacks for the headphones and the paddle did not stick out far enough through the case. I tried to adjust but messed it up even worse. Steve, KD1JV, was kind enough to give me his prototype case and it fit perfectly. In fact, I like the prototype case better than the final kit case. The silk screening is just a bit different and for my tastes, I like it much better.

The radio puts out just a bit under two watts with the internal AAA batteries. I already worked KI0II in Colorado with this rig on my normal HF antenna. With 12 volts the radio puts out a solid four watts or more on all bands.

After the rig was completed and the first contact was in the log, I felt I needed a nice little case to carry the radio and boards. Using a very inexpensive Walmart school pencil box, I was able to put the main radio and boards neatly into the available space. There is room for all extra band modules, a spare set of batteries and on the right near the antenna jack there is room for the adaptors ( to go from RCA to other type plugs). I even had room for my Sony headphones. There are foam inserts that hold the modules, batteries and radio in place while traveling. I also plan to carry a light-weight paddle, maybe a light straight key and the antenna in a Ziploc bag.





This was a fun kit. I don't hike in the field much so this radio may end up in the hands of someone in the Lower 48 states (Sold to Alan, N3BJ, Bent Mountain, VA). It will be better appreciated that way. It would even make a great radio for just sitting at a picnic table at a park and making a few QSOs. The specifications taken from the KD1JV website are as follows: .. (http://kd1jv.qrpradio.com/)

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