KD1JV AT SPRINT- III

Steve Weber has been designing very small, light weight backpack rigs for his own pleasure for several years. Because others wanted to build versions of his design, Steve agreed to "kit" the transceivers. This is the third in a line of very portable amateur radio transceivers he has designed and built. The ATS-III covers four amateur radio bands, 80 through 20 meters and operates in the CW mode only. Click on the above picture to visit Steve's site.

I wanted to build the AT Sprint-II but didn't get it ordered before the kit sold out. I was determined to order the ATS-III as soon as Steve announced it for sale, which I did. The ATS-III is not for everyone because of its small size, the transceiver will fit into a normal size Altoids box. It is built using mostly SMD 805 size chip components. I had built a couple of other projects using these small parts so I wasn't too worried about giving this rig a try. Below you see the circuit boards as they come from Steve. The picture on the left is shown before the boards are separated. On the right you see them after separation and before the band module boards were trimmed.

I got started as suggested by Steve, mounting all the surface mounted IC chips. Here is my board with those components mounted.

Next came all of the capacitors. These parts are very small, about the size of short grain rice. The back of the board is shown on the right below.

My Weller solder station quit working so I'm off to Fry's to see if I can pick up a new pencil for it. More to follow. Well, that sure turned into a tough job. I got to Fry's on Friday after Thanksgiving it took me about 20 mins to get in the parking lot. I found the replacement pencil and started looking for the end of the check out line. Finally found it near the entrance, I asked someone in line how long they had been in line and they said "40 mins" and they were at least an hour from getting to the check out stand, I decided to try back later in the afternoon. Returned to Fry's in the afternoon and stood in the check line for about 5 mins.

I finished up the ATS-3, the front of the board is on the left and the back on the right, they have been cleaned of flux and ready for inspection.

 

Here is one of the band modules

The above view shows the ATS-3 with the plug ins for each band.

I now need to inspect the boards and start the checkout. I haven't decided on a case for the rig. Since I'm not concerned with weight I am thinking of using a TenTec TP-17. There will be plenty of room for a 9 volt battery and space for the plug ins. The problem with this style of case is figuring out how to make it "easy open".

I decided to put the rig into an Altoids box, although I might change it to the TenTec case later. I started by drilling the holes for the controls. Below are a couple of shots of the sanded case. I didn't notice the many little "dimples" in the box until I had the holes drilled and most of the paint removed. Oh well.

 

The finished rig is shown in the following two pictures. I used a BNC connector instead of the RCA jack provided in the kit. It adds quite a bit of weight to the rig, so those interested in keeping the weight down should use the RCA connector. I had to shorten the BNC pin so that it wouldn't short out on the circuit board, it's still pretty close!.

This has been a fun little rig to build. I didn't lose any of the very small parts, although I had a couple of close calls. Those little devils like to go flying if you put too much pressure on them. I was able to recover the two that went flying on me. I did have one mishap, Steve sent me a replacement for R22, which was a changed part from the original. It came tape to a piece of index card and when I took the scotch tape off the carrier it pulled the cover off the carrier and the resistor went flying into never-never-land, never to be seen again. I found a 270 ohm 1206 size resistor, there was just barely enough pad peeking out to solder to.

I haven't put the ATS3 on the air yet, although I've listen around on all four bands. I have to repair my QRP dummy load before I can do the final tweaking on the transmit side.

I finally fixed the dummy load and checed each of the bands before putting the ATS3 on the air. I am getting about 5 watts on each of the bands with 12 volts. Below is a picture of the rig on 40 meters putting out 5 watts. Guess I'll call it finished and move on to something new. I'll probably be starting on the 2N2-20 in the next week or two but first I'll finish up the Miniboots amplifier.