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During the period when spread spectrum was just coming into use for ham radio, SSS Online's founder, Randy Roberts, was very involved in creating design ideas. The original diagrams and the first piece of text were posted on the site on April 13, 1997. The second piece was posted November 6, 1998. No changes have been made to the content of this page since that time; all revisions are to format and advertising.

HAM RADIO SST Block Diagrams

Here is a Detailed Set of Block Diagrams for the Proposed SST Radio for the TAPR SS STA/ Next Generation FCC, Part 97 - SS Rules

By Randy Roberts, KC6YJY


Top Level SST Block Diagram

OK all you "SS fans" out there -- here are my very latest thoughts on a modular, low cost SS radio design for Ham Radio. The block diagram above shows the top level, sort of interconnection view of the new design that I have in mind. After following the TAPR SS SIG for several months and watching our email from all of you, I have incorporated a few changes to the previous Ham Radio SS schemes.

This design can use either the STEL / ZILOG DSSS baseband chips OR the Harris PRISM baseband chip (HSP3824). Note from the following block diagrams that almost all of the other chips in the Harris PRISM Chipset are used in this design.

The design is modular and flexible enough to allow "a mix and match" of PCBs to allow Frequency Hop Modulations to be used, as well!

Finally, my favorite SS Modulation -- namely "Hybrid" combined DS / FH is easily accommodated in this design, since the Harris Dual PLL synthesizer IC (the HFA3524) can switch up to 50 MHz (at 2.4 GHz) in under 400 microseconds! Please realize that NOTHING in this design, so far, is "locked in concrete!" In other words, we are very open to suggested improvements, simplifications, etc. This design is intended to overcome some of the criticisms of our previous "ideas" for a Ham Radio SS design. This design is NO LONGER "band specific" -- even though we have shown a concept here for the 2.4 GHz band. Other IF or RF PCBs can be designed and accommodated for many other frequency bands. Also, the scheme presented here allows both DS AND FH modulation formats to be transmitted AND received without worrying about "Band Specific" transverters and their non-linearities, group delay distortions and similar "little" details.

This is just the very first, small introduction to this design -- I plan to add a lot more design description details and related ideas, as time permits!

Please take a look at the concepts presented here -- I'd love to hear from you with constructive criticisms and I'd very much like to hear your ideas! Just drop us an email: [Editor's note: Randy's email is no longer active] or post something on the TAPR SS SIG: -- 73 for now!


"Basic" SST Baseband (BB) Block Diagram


Harris "Prism" Option SST Baseband (BB) Block Diagram


Frequency Hop MX-COM Option SST Baseband (BB) Block Diagram


Frequency Hop TI DSP Option SST Baseband (BB) Block Diagram


SST IF Block Diagram


SST Frequency Hop Option IF Block Diagram


SST LO Block Diagram

SST RF Block Diagram

Download ALL ORCAD Capture .DSN Block Diagram Files (Zipped ~19K)

Download ALL ORCAD Capture Files [ in .DXF Format ]
Block Diagram Files (Zipped ~26K)

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