I have a real attraction to small rigs and Steve Weber's little ATS series and especially the ATS-3. It is a fantastic rig. It is lightweight in size but heavyweight in performance. One aspect to this hobby is seeing how light you can make a rig for the trail, yet still have it be functional. The Spartan Sprints are the perfect practice for experimentation. I have been tinkering with this rig for over a year now and still have a ways to go, but this is my attempt to document what I have done to date.

My first plans were to use the ubiquitous Altoids tin. There are several ways to prep the tins but the one that I found easiest is to burn the paint off with a torch. This makes a nice patina finish on the metal, sort of an antique look. Another enclosure is the sardine tin. It is lighter than the Altoids tin, but smelly for my tastes. Hi. Lately I have been using a plywood/balsa box that is just as light as the sardine can and surprisingly sturdy.

The box is 1/32” plywood for the top and 1/8” balsa wood for the sides and bottom. Carpenters glue and cyanoacrylate (superglue) was used for construction.<!--[if !vml]--><!--[endif]-->

As you can see, this is a weight of 3.0 ounces with 2 of the band modules.

Other areas of weight savings are the battery and key and headphones. To be competitive in the sprints you must use a Lithium Polymer battery and make your own key. The LiPo batteries take some special handling and you must use care in charging them. Please read the instructions before using them. These LiPo batteries are in many cell phones sold today and the R/C hobby uses them extensively. They come in many capacities so judicious selection, can help in weight reduction. AeroMicro is one supplier of batteries and chargers. (No connection with them, just a satisfied customer.)

Your key can be anything from two wires to something more elaborate. I am using two switches (similar to the switches in the ATS-2) glued together with a short pigtail cable to a stereo plug. My key is on top of the box in the picture. If I could master a cootie (side swiper) key I could use just one switch.

As far as headphones go, get several and weigh them, then use the lightest pair. My current favorites are Sennheiser MX-550's. You could even cut off one of the pair to make a mono earphone.

There are several other ideas such as plastic screws, carbon fiber enclosure, solder all external connections to eliminate jacks and plugs, even removing some components from the main board that aren't strictly needed for cw operation. I won't be doing the more extreme modifications, as I never know how long a rig will stay in the fold and want to preserve resale value.

By the time this is published, 2.5 ounces (0.156 lb) should have been broken in the December Spartan Sprint. I look forward to hearing other lightweight rigs and operators in the future. So get your rigs on a diet and get on the air on the first Mondays of the month. Even if you don't want to do the weight competition, get on the air with any rig – it is a blast!

UPDATE – 12 December 2005

Well after a little tinkering the weight is down to a mere 2.4 ounces (0.150 pounds) for 2 bands. I ran this rig in the December 2005 Spartan Sprint.

UPDATE - 20 Mar 2006

Weight down to 0.135 (two bands). I have removed the key that is pictured above and replaced it with a more friendly, one handed operation key. Hope it will make keying easier. :)

This is the rig with battery and earbud (singular). You can see the key connector below the 'up' button along the bottom of the rig.

Here is the connector for the key. The key is built into the bottom cover, secured with a little epoxy.

The bottom cover removed and turned 90 degrees and plugged in, ready to go. With a new battery (not shown),  the weight will be no more than 0.135 pounds for 2 bands for the April 2006 Spartan Sprint. Hope to catch you on the air.

UPDATE - 16 August 2006

Here are the latest pics. Imagine this case with very lightweight plastic for coverings (think monokote). 1 band weight 0.100 pounds, 2 bands 0.113 pounds. Note this is a different main board than the one shown above. That one now has a new home! This is my original ATS3 rig.