High Performance Software Defined Radio

An Open Source Design

Project Outline

The following is a project outline that describes a typical HPSDR project flow. We provide this as an example but the process can vary by project specifics. The outline is also modeled on hardware projects but may vary substantially for software projects.

The HPSDR group is a set of experimental minded radio and computer enthusiasts that want to advance the state of amateur radio. We realize that we are all amateurs and, therefore, time lines vary because of the time available to pursue our radio hobby.

A general hardware project might include the following steps:

Once you think you may have a project idea, you should propose the project both on the list server and if you get some interest, request a Wiki page for your project. The Wiki is a location where the project leader can place information that is more detailed than can be placed on the e-mail list. Additionally, old e-mails are time consuming to search and the Wiki provides the information on the project development in one place.

Feature Specification
The project leader first specifies the project features. Other group members will likely suggest additions or changes to make the board more useful for their application of the HPSDR board suite. The project leader may reject some suggestions as they may be very difficult to implement.

Initial Design
At this point, the project leader will make the block diagram and schematic of the project board. This is probably the most important step in the project development. Group members will make a number of comments to improve the circuit.

Breadboard (Optional)
If possible, it is a very good idea to breadboard the circuit. This is a practical proof of concept. Many of the HPSDR boards have been breadboarded before the initial build yet sometimes it is not possible.

TAPR proposal (Optional)
Sometime in each process, at about this step, a proposal can be made to TAPR for funds to build the boards. Building printed circuit boards is usually a very expensive process and it assures the project leader that the board development is worth proceeding. TAPR proposal examples can be found on the Wiki. If an project leader skips this step they will need to take on the cost of producing the alpha boards and testing.

Design Printed Circuit Board
When the Project Leader feels that he is ready to proceed, the next step is to create the printed circuit board (PCB) design. The project leader can do this work himself if he has the skills or there are a few group members with extensive experience in PCB design that will translate your schematics into PCB Gerber files.

Alpha board production and testing
Given the PCB is acceptable, a set of Alpha boards are built to test the circuit design and test the board performance with several volunteer group members. Some boards work well and need minimal rework. Other boards in the past have required more extensive rework and the building of a second alpha board set.

Interest Call
The next step is to make an interest call on the hamsdr.com website to determine the number of people willing to purchase boards prior to production. In this example, TAPR does not have sufficient funds to support the entire run of a board production so the group members assist in the funding of the board production by ording boards in advance. The ultimate cost of the board is based on a number of factors including the cost of the components and the number of boards built.

Distribution production by TAPR (Optional)
If TAPR support was granted in the the optional step above. TAPR would expects to recoup its development costs in this step. TAPR will generally build the number of prepaid boards plus some number of boards that TAPR decides they can financially support. The boards are sold through the TAPR website. The TAPR mission is not to be a provider of radio boards but to support the development of the radio technology. They must recoup the invested production and development costs in order to support future projects.

Documents made available to other producers
Since HPSDR is an open source hardware and software development project, all project considered part of HPSDR should accept some open source license. TAPR is the only organization that has proposed an open source hardware license. Because TAPR generally produces only one production run, and HPSDR projects generally use the Noncommercial Hardware License or the Open Hardware License, all the files necessary to build the boards may be placed on the HPSDR website. This allows those interested in producing boards to make them available to amateur radio operators that have not already obtained a board.