[ICOM] ICOM marine/ham radios

[Ed Senior]

Hi Ben -

You make some good points.  However, your understanding of
analog versus digital techniques may be a bit biased by your
evident enthusiasm for the latter.  Specifics interleaved below...

----- Original Message ----- 
From: "Benjamin E Lamb" <benlamb at juno.com>
To: <icom at mailman.qth.net>
Sent: Friday, June 10, 2005 9:38 AM
Subject: Re: [ICOM] ICOM marine/ham radios


>
> Heres is another penny's worth...
>
> Sounds kind of foolish to have two 'separate' radios; and it is.
> Law follows technology.
>
> The FCC regs were written during the Analog Vacuum Tube Era
> and actually made sense at that time.
>
Agreed.

> Today digital technology is capable of providing rock-solid frequency
> stability (1 Hz/GHz using a disciplined oscillator) and with DSP
> technology  nearly perfect filters are realized.

The high-stability sources to which you refer are frequency synthesizers.
(BTW, "disciplined" is not a term I have ever heard applied to oscillators;
but the context makes it pretty clear what you mean.)

Synthesizers may be realized in various ways; but they all start with 
a highly accurate source or clock.  These clocks (e.g., crystal-
controlled oscillators) are more "analog" than "digital."   

The balance of the synthesizer circuitry (e.g., dividers) can be analog, 
or digital, or both.  These days, digital circuits would predominate, 
mostly because they are cheap.  But a pure analog synthesizer would 
be no less accurate than its (partially) digital counterpart.

As to filters, there are many attractive aspects to DSP implementations.
And if one overlooks quantization effects, the filtering algorithms can be
described as "nearly perfect."  But since the source signals are analog,
DSP filters must be preceded by analog-to-digital converters.  These
ADCs are not easy or cheap to design for high performance.

> All the technical
> standards imposed  by law may now be controlled by software.
>
Well, the technical standards are controlled by regulatory agencies
such as the FCC, and engineering groups such as the IEEE.

But I expect you meant to say that a given radio's compliance with
technical standards can be "controlled by software."  In the case
of a software controlled radio, this would be substantially true--
assuming there is appropriate hardware to control, of course.

> The above facts will in time lead to new regs that permit
> multiple-service radios; i.e. - Amateur, Marine, Commercial, etc.
> I believe that eventually encrypted keys will be issued to licenses
> to permit cross-service operation.
>
This is quite a nice and visionary idea, within reason.

But the hardware still has to be appropriately selected and packaged.
One-Size-Fits-All might present some problems, in that an Amateur
might not want to pay for Commercial quality components, or for
Marine waterproof housings.

> SOFTWARE DEFINED RADIOS will RULE !
>
You're probably right about this--but primarily because they will be 
cheaper.  Enjoy "real" radios while you still can!  8-(

> Ben K1AUE
>
73, Ed, W6LOL
>
>