On Fri, May 22, 2009 at 10:02:31AM -0700, Larry wrote:
> Thanks to all that responded with info and ideas. All good stuff and
> things to think about. I am learning a lot from these discussions.
>
> However, there seems to be a trend towards "design excellence" which I
> cannot justify. This is for a amateur radio HOBBY application, not for
> medical electronics, manned space flight, or government funded weapons
> systems. Been there, done that, and retired from it! It ain't no fun for
> this guy anymore.
>
> I am striving to return to my roots, if you will, where all my equipment
> was built from stuff I found in trash cans around the neighbor hood.
> I.E., free or cheap.
[snip other stuff]
I'm in this to learn. I know how to build a linear supply; I probably
could do it in my sleep, and I'm pretty sure I'm not the only one. I'm
also not getting younger, and really am not up to lugging Big Iron
around. The alternative is an SMPS, which is new-to-me technology that I
want to understand better.
I've never done weapons systems or medical electronics, but I used to
throw guys up into the sky and get 'em back down again, during Project
Gemini and the early part of Project Apollo. I loved it, and can't think
of a better first job for anyone. Now I work for the largest engineering
organization in this state, doing lots of computer-related stuff. Not as
exciting, but useful, interesting, and it pays the bills.
I'm not at all sure I can object to a trend towards doing things better,
but don't see how a different kind of power supply can be classed as
doing things better: it's just doing things a _different_ way, as
are synthesized frequency sources, digital signal processing, spread
spectrum technology, and software-defined radio.
I'm a great fan of dialing up a frequency and having the radio sit
*right* *there*. My HP 8640B, which for its time was state-of-the-art,
doesn't do that, quite; it drifts a little bit. It's not as bad as
hearing an entire Swan net drift through my receiver's passband in
synchrony, and it's good enough for most purposes, but my personal
preference is for stuff that can be phase-locked to WWV and stay put.
I used to droooooool over the concepts, and thought the HP 5100 would
make a marvelous local oscillator for a radio. I still think it would,
but it has been miniaturized down to a single chip, and my sand-state
transceivers all use one.
DSP and SDR are marvelous. My SDR receiver lets me see and record 190
KHz at once, demodulate two signals at once live or from the recording,
and tune around without having to adjust a single RF component. The
DSP in my Yaesu FT-857D and FT-897D let me narrow the passband down to
240 or 120 or 60 Hz for CW, or tweak the upper and lower limits of the
digital filter, so that I can hear the signal I want and not the QRM
or QRN just outside. In addition, I can place a notch anywhere in the
passband to get rid of a really nasty heterodyne. I can't do that with
my R-390 or R-390A, which used to be the best receivers in the world
(with the possible exception of the R&S EK-07). And because the LO in
the Yaesu rigs is synthesized and based on a very stable oscillator, the
rig stays where it's put.
Spread spectrum gives us a way to have multiple signals occupy the
same spectrum without material interference, and to transmit with
an extremely low probability of detection by ordinary receivers and
instruments. Variations on these techniques get images back from probes
sent to planets and planetary satellites all around the solar system.
One of my uncles was in at the beginning of this, when it was called
RACEP (and later SHADOW), and I thought it was magic. I still do,
even though I now understand the mathematical bases underlying the
technology, and I use it and related techniques every day -- in my cell
phone (also magic), in my GPS receiver, and in my cordless phone at
home.
I'm a fan of the digital modes, though I also operate CW. The digital
modes require stable transmitter and receiver, and generally use some
sort of DSP. With the exception of RTTY, they're pretty new, and they
provide ways to get data moved through hefty QRM and QRN. The weak-
signal modes, in particular, are designed to do things that I wouldn't
have thought were possible for hams when I got started in the hobby in
1962.
I see nothing at all wrong with using contemporary techniques in my
hobbies. I certainly see nothing wrong or objectionable about trying
to improve the way my equipment performs. I also see nothing wrong
with building and using a 6L6 or 807 MOPA transmitter and a regen or
superregen receiver, stone-knives-and-bearskins though they may be when
compared to the top-of-the-line all-digital SDR-based gear available to
those willing to throw enough money at the problem. There's room for
everyone in this hobby.
--
Mike Andrews, W5EGO
mikea@mikea.ath.cx
Tired old sysadmin
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