Project Status: March 1, 2017

[NZ0I]

To those new to the group, here's the status of various aspects of the Receiver Development Platform:

1. SCHEMATICS

The latest schematic diagram is Rev B.22, and it contains 10 sheets containing various "modules" of the complete project design. Only the first seven sheets have reached a moderate level of maturity, having been modeled, and to some extent built and tested in the first round of experimental PCBs. None of the transmitter design has been built or tested at this point, and the transmitter schematics are incomplete, and still being updated on a regular basis. 

2. MODELING

Much of the schematic design has been modeled in SPICE, but on a sub-module basis. That is, there is not a full integrated SPICE model for the full project, but a majority of the design has been modeled individually as filters, amplifiers, bias circuits, etc.

3. PCBs

Each of the 10 schematic modules could, in theory, be placed on any combination of PCBs. The entire project could be built on one great big PCB if one desired. But currently the modules are divided among five PCBs, but only the first four have been designed and fabricated.

• Receiver Board
  
• Digital Interface Board
  
• UI/PS Board
  
• 80m ARDF Antenna Board
  
• Dual-Band Transmitter Board (not yet laid out)
  

The second round of boards, dubbed Rev X1, have just been built by OSH Park, and are undergoing preliminary inspection before being populated. Three of each of the first four boards was fabricated. The X1 boards reflect the design shown in the first 7 sheets of Schematic Rev B.22.

4. HARDWARE

The very first round of experimental boards were fabricated and built in the fall of 2016. They were used to prove portions of the design: User Interface, Receiver Power Supply, Processor, Audio Amplifier, and Receiver IF. The first boards were valuable for identifying several problems with the original design, illuminating improvements to the overall concept, and providing a high degree of confidence that the second round (Rev X1) will be a marked improvement, and will likely meet most project design goals for receiver sensitivity and overall functionality.

5. RESOURCES

In addition to this Google Groups email reflector, the project has a shared Google Drive folder containing virtually every document related to this project. Those wishing to utilize those resources will be given access to that folder: just contact me to be added. The Google Drive space is finite, but it is free of charge. You too can create your own Google Drive account for free, and use it as you wish. If you think that you might be generating your own content useful for this project (> ~500MB), I would encourage you to consider creating your own Google Drive account, placing your files there, and sharing pertinent folders with others involved in this project.

Bare PCBs will be made available from OSH Park once proven PCB designs are available. Rev P1 boards (first prototype - hopefully the next revision after X1) should be the first candidates for release. But I will want to make sure that those boards contain all that is learned from Rev X1 - so I don't expect them to be available before mid 2017. If anyone wants to purchase boards sooner, just let me know and I can release them early for those wishing to build and debug an early release.

QUESTIONS & COMMENTS

Questions and comments are always encouraged. Feel free to post to this email reflector, or to email me directly. Everyone's time is limited, and it is understood that you might have precious little time to devote to this project. No problem. You are welcome to follow along, drop in, drop out, and otherwise go with the flow. If this project is helpful to you in any way, then it has fulfilled its major purpose. If you can contribute a suggestion, comment, or insight, then great! Your input is valued and appreciated.