Update! Buildathon Completed - Pictures Available

This just in . . . the MARS SDR Buildathon was run successfully at the appointed place and time. A great and educational time was had by all participants. Three builders completed their radios. Several builders were jinxed by an early error in the documentation where your color-blind documentor specified the wrong color codes (in words - the pictures, the color codes and the BOM values of the resistors were correct). This lead those builders to sort their resistors out by stage, but using the wrong values. One stated it succinctly:
"Being colorblind, I read the color codes written in the BOM out to my wife and she found the matching resistors and put them on my stage-by-stage component organizer for me!"
Elmers had quite a time figuring out why the Local Oscillator stage was in some cases drawing way too much current and in others drawing way too little. In retrospective, it should have been obvious; as one club member who is very experienced In these matters stated, "Its a resistor problem!".

Take a look at the photos of the festivities to include the MARS club's "HAMS & EGGS" regular Saturday morning breakfast meet prior to the event


Metrocrest Amateur Radio Society (MARS) will conduct a Software Defined Radio "Buildathon" on 11 July 2009 at Carrollton Public Library, Hebron Branch 4220 North Jose Lane Carrollton, Texas (map).

The event will allow registered participants to construct and operate a fully operational Software Defined Radio Receiver fora segment of the 20m Band. The construction will be via a "Softrock SR_Lite II" kit (costing $13.00, postpaid). The construction is documented in the "Heathkit" style and proceeds through several stages, each with its set of stage-end tests to verify the build is correct.

During the Buildathon, several club members who have successfully completed the build of this kit will be on hand to act as "Elmers", guiding and assisting the builders and providing special test equipment for the various tests that are conducted during the build. There will be special stations to provide hands-on assistance to builders in the techniques of SMT soldering and toroid coil winding.

Registering for the Buildathon

Participation in the Buildathon is open to all members of MARS. In addition, members of neighboring ham clubs are invited to participate. To participate, the club member must printout and complete the Buildathon Registration Form and return it, no later than the Club Meeting on 14 May 2009, along with a check for $13.00 to cover the cost of the kit, to:

			< < registration is closed for the July Event > >

(you can order directly from the designer at his Softrock web site)

Preparing for the Actual Event

Detailed Preparation Instructions

This event is an ambitious undertaking and demands the upmost in smart organization and preparation. We have prepared a set of "Getting Ready for the Event" instructions that the registered builders can and should read and comply with in order to be well-prepared for the event and help make the most of the time and resources allocated. If you are a registered builder, please download, read, and comply with these instructions.

Builder Notes - How to Build the Stages

The builder must have his builders notes ( the stage-by-stage "Heathkit" instructions) printed out and available at their builder station. You cannot build the kit without them

Organizing the Passive Components

One of the first things you will do in getting ready for the event will be to inventory and organize the components. We have provided a set of Bill of Materials Component Organizer Sheets, specifically laid out to help you organize the passive components by stage of the build. The result would resemble the picture below:

Components as Organized on the Sheets

Builder's "Buildathon Go Box" Checklist

Use this checklist to make certain you have everything done and ready to go on the day of the event in your "Buildathon Go-Box".

Power, Stereo audio
Stage-by-Stage Instructions Printout
Wound Inductors(Optional)
Kit, with Components Organized(We do not have spare kits!
DMM(labeled with your call)
Solder Station(labeled with your call)
3rd Hand/Vise(labeled with your call)
Light and Magnification(labeled with your call)
Cookie sheet(labeled with your call)
Power Strip(labeled with your call)
Grounding wire/clip
PC(Optional)(labeled with your call)
Safety Glasses


PC and Software

Since the radio is a Software Defined Radio, the builder will need a PC or Laptop, using freely available SDR software, in order to actually operate the comleted radio. You may bring your laptop, if you have one. However, you can still comlete the build and test your radio, using the Elmers' laptop at the "Final Test" Station.


In order for the builder to maximize the use of the time available for the Buildathon, the table below outlines the types items that are necessary for the builder to have on hand at his/her builder station during the event. It is not intended to direct specific items, however, to the extent that the builder can bring these or similar items to the event, this helps the club keep the costof the event down. No participant will be turned away if they really want to do the build, but cannot afford the needed infrastructure itrems.

Be sure to label your tools and equipment. In a multi-builder environment, stuff gets mixed up pretty quickly.

Items marked with a star are "builder's preferred", i.e., builders consider these the ideal tool for the requirement





Cookie Sheet
  • Uncoated Cookie SheetNOT non-stick
  • $1.00 Dollar General Store (next to Harbor Freight) work surface: important for ESD protection and protection against lost components.
  • Baking Pan - 18" x 26"
  • $8.77 Sams Club #127108The cheaper one works, but is a little cramped sor space. (Sams also has a half-sized 18x13 for $5.12)
    ESD Solder Station $19.99 Frys #4825190 Velleman VTSS5U
    DMM $4.99 Harbor Freight 92020-1VGA

    Check for on-sale
    3rd Hand Capability

    • 3rd Hand
    $5.99 Harbor Freight
    (3rd hand with magnification and light. Not too sturdy, however.)
    • Panavise, Jr.,
    $24.95 Frys 1917851 (This is the ideal 3rd hand tool - very stable. If your budget can afford it, get it!)
    • Mini Vise
    $3.49 Velleman VTTV3,
    (another possibility for 3rd hand capability. Would be my last choice.)

    • Lighted, Magnifier Headband
    $9.99 Harbor Freight 95890-5VGA One way for lighting AND magnification
    • Desktop lighted magnifier
    $5.99 Harbor Freight 96358-1VGA Another way for lighting and magnification
    • Desktop Magnifying Lamp
    $17.99 Harbor Freight 97448-2VGA Builders prefer this one over all others. Also available at Frys for a couple bucks more.
    • Desktop Magnifying Lamp
    $19.99 Office Max #21661881, Catalina Full Spectrum Flip Task Lamp
    Eye Loupe SET $2.97 Harbor Freight 47995-2VGA For super fine inspection (up to 10X) of tiny components, completed work
    Tweezers $4.99 Harbor Freight
    A set of tweezers
    Diagonal Cutters $6.59 Radio Shack 64-2951

    Kronus 4.5” diag cutters
    Wire Strippers 5.99 Radio Shack 64-2979 Kronus™ Adjustable Wire Stripper
    Diag Cutter/Stripper Combo $5.99 Combo: Harbor Freight, #97871-2VGA Combo dikes and wire stripper. If you do not already haveseparate cutter and stripper, this is the one to get.
    9V Battery Anywhere

    9V Snap Lead 4/$1.00 Tanners Club has a few spares
    3.5 mm Stereo cable & plug (or panel jack) $1.49 (or $0.69) Tanners Builder’s choice: cable and plug or panel jack. Club has a few spares of each
    PC w/SDR Software (Optional) n/a Builder Builder’s laptop PC loaded with Rocky or Winrad SDR Software. There will be one of these at the "Final Test" Elmer station.
    Multiple Outlet Power Strip $3.99 Builder; Harbor Freight 91334-3VGA Due to the number of builders, a 4 (or more) outlet power strip is essential.
    Grounding wire ~$1.00 Builder (make one from a three-prong plug and a single wire to bring the ground connection out to an alligator clip to clip to the cookie sheet) If you are not using a anti-static mat, this is highly recommended as an ESD safety measure.
    Safety Glasses$0.99Harbor Freight ITEM 99762-0VGABetter to be safe than sorry. Hot solder blobs can wreak havoc in your eyes.

    Minimalist Builder Station

    This is a minimalist builder station that you can put together for under $50.00 (assuming you start with nothing) Minimilist Builder Station

    The kit

    The kit comes in a small ziplock bag and provides everything except the external connectors and 9V battery. The connectors are:

    • A builder-furnished 1/8 " stereo plug and cable (or, alternatively, a 1/8 " stereo jack), available from Tanners. This connects the radio to your PC's Soundcard Line-in. (The club has several of these available, as well)
    • A builder-furnished 9V battery snap connector. The club has several snap connectors availanle, as well)
    • A club-furnished short length of RG174 coax to connect to the radio's antenna terminals (builder may elect to provide an appropriate antenna jack to solder to the other end of the coax)
    • 0.015" eutectic solder. The club can furnish this (we'll have a pound of it available for the event)

    The Finished Product

    The topside view

    View of Completed Top

    The underside view

    View of Completed Bottom
    DMM Listing 3rd Hand Listing Combination Diag Cutter/Wire Stripper listing Tweezer Set Listing Set of Eye Loupes - Listing Velleman Solder Station Listing
    Power Supply Components Local Oscillator Components Divider (no passive components to organize) Band Pass Filter Components Operational Amplifier Components Mixer Components