[TenTec] [Orion] "Technical Correspondence", August 2007 issue

[Dr. Gerald N. Johnson]

On Wed, 2007-07-25 at 11:33 -0700, Kevin Purcell wrote:
> Thanks not what I said.
> 
> I was asking what value their closed software adds that would be lost  
> if they opened their software.
> 
> Do they have trade secrets in their implementation that add value  
> that they wouldn't want others to see? I don't see it in the feature  
> list but it may be in performance of their code (for example).
> 
> Would they benefit is the open-sourced or partially open-sourced  
> their software. What have they too loose? What do their customers  
> have to win? Would it sell more hardware or improve their  
> "intangibles" (like customer satisfaction or customer service or even  
> software quality or time to find and fix bugs). Would it help them in  
> multiple markets by propagating those bug fixes or new features to  
> other markets? Would it help them against (potentially more open)  
> competitors?
> 
> It seems to me that TenTec, like Apple, makes its money on selling  
> hardware that happens to run software (so to speak). But perhaps they  
> consider their software a core competency?
> 
> Apple uses an interesting approach where some of their software is  
> open-sourced and some of it is proprietary (the software they use to  
> add value).
> 
> As others have said for me amateur radio is about experimentation so  
> the ability to experiment with commercial hardware (by say tinkering  
> with the software just I we tinker with the hardware).
> 
> I focus on TenTec here but this applies to other companies too:  
> Elecraft, FlexRadio (Windows only ... whats with that?), Icom, Yaesu,  
> Kenwood, etc.
> 
> Some may wonder why this discussion is here but for me (and some  
> others) it's an increasingly important consideration when buying  
> amateur radio equipment that is dependent upon it's software? For how  
> long will the company support this hardware and update/bug fix their  
> software? For example, the ethernet connectivity of the O7 raises  
> interesting issues of security that we've already seen the operating  
> system world deal with.
> 
<SNIP>
> --
> Kevin Purcell
> kevinpurcell at pobox.com
> 
There is a fundamental difference between the TenTec and the various ham
SDR that have open source software. The many SDR use PC audio cards for
the A/D and then do ALL the computation in the PC external to the radio.
Sometimes only a certain few audio cards will work fast enough. TenTec
radios use a special purpose collection of micro and DSP chips IN the
radio where the needed compilers are not necessarily available on the
consumer computer market.

And then the SDR of the current market are direct conversion radios with
RF stage, a LO with quadrature outputs and a couple mixers with low pass
filters and gain stages having probably no more than 150 KHz bandwidth.
The software controls the LO in large (maybe 10 to 50 KHz steps) and ALL
the fine tuning, filtering, and detection is done in the DSP software
running in the attached PC. The simple rock locked radios neglect the LO
tuning and cover a big chunk of band all with the DSP software in the
computer. The ultimate radio performance depends on the dynamic range of
the RF and mixer and tremendously on that of the A/D converter. And for
the PC many compilers are available allowing diversity in programming
language as well as operating system.

In TenTec radios, the LO is controlled to the finest of frequency steps,
the RF is bandpass filtered then at the IF its filtered more with the
"roofing" filter, then converted down to a 15 KHz IF where the direct
conversion Q and I process is done and then the fine filtering, very
finest of tuning (if the roofing filter allows), and detection is
accomplished in the DSP. So the software does a great deal more radio
control before the DSP and with the use of narrow "roofing" filters the
DSP hasn't all that much to do. That makes most of the dynamic range
depend on RF hardware and allows a smaller dynamic range and narrower
bandwidth A/D but exposes the radio design to all of the same foibles in
dynamic range and close in intermod of multiple conversion analog radios
that have been fought for decades. But TenTec has known how to produce
radios with good dynamic range for nearly that long too.
-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer