Electronic Design and Family Site

               GoLiaTH

the Green Lakes Trail Hiker

    I own an ATS3-B designed by Steve Weber, KD1JV.  This radio is a multi-band (80M to 15M) QRP CW Transceiver that can fit in an Altoids tin and operate from a 9V battery.  I almost solely use it to operate ARRL Field Day but occasionally take it on vacation with me so I can operate special events (like SKCC Weekend Sprints).  It's easy to transport and operate and performs surprisingly well.

BUT...

    My ATS3-B is over 10 years old, not packaged particularly rugged or waterproof, uses obsolete parts, and uses firmware I can't modify.  If this rig ever dies, there's a huge possibility that I may not be able to repair it.  Thus was born the desire to design and build its replacement myself.  That way, if I ever need to repair it, I will have spare parts already (I store multiples of any unique parts in case of future failure), I will have the capability of programming the firmware into a controller of my choosing, and I can modify/upgrade it myself should I desire added features.

 

The name for this radio comes from my favorite hiking and operating spot, Green Lakes State Park near Syracuse, NY.

 

    Since I had a well operating unit already, I used that as the baseline for my design.  I borrowed heavily from the original  ATS3-B design, making changes to add (or remove) features, replace obsolete parts, and work with my more preferred parts.  Some of the largest changes involved using an Si5351 oscillator IC instead of the older and less capable AD9834 DDS IC.  Since the Si5351 is much more processor intensive, I also replaced the original processor with an Arduino Nano.  I also added on-board SWR measurement and a full-time battery voltage monitor. 

    The original design was simply a set of boards that could fit into an Altoids tin.  Tiny, but not very rugged.  My iteration was designed with a specific waterproof chassis in mind to (hopefully) improve ruggedness and water-resistance of the radio.  The clear top of the chassis allowed me to easily use a full-time display rather than the CW annunciator KD1JV used on the original without compromising the water-resistance of the cover.  I also wanted a rotating tuning control rather than use pushbuttons to tune the radio.

 

The Schematic of the "Analog" board is below, if you wish to download it, Click Here:

 

 

The schematic of the Digital board is below, or you can download it Here.
Finally, the schematic of the filters is below and can be downloaded here.  I had extra space on the filter PCB so I included an alignment jig.  You plug a filter board into the jig, attach a NanoVNA to J6 & J7, set the jumper for either 50 ohms to test transmit Low-Pass filters, or 1500 ohms, the input impedance of the first SA612 mixer, and test the filter response.  You simply switch the direction in which you insert the filter board to test either the Tx LPF or Rx BPF.

The second prototype of PCBs arrived yesterday, so I'm only publishing the schematic until I know whether these PCBs function well or not.  If so, I'll publish the PCB Layouts too.  Then once the project is built into its chassis, I'll publish the entire BOM and build article.

 

Keep checking back here to see my progress!