Allison wrote:
Actually the sound card modes like WJST and PSK31 only
need the sound card
to aquire the signal at audio baseband then the CPU does the heavy lifting.
There is also software defined radio, all modes (AM/FM/SSB/CW) where the
CPU after aquiring quadrature baseband does the decode work, the RF portion
of a reciever can be simple to the extreme but provide prformance and
features at the upper end.
Call me a old fart but I still like Analog Radio and real music rather
than digital this and that. I still think the BEST radio's are still
ones built by hand rather than a mass market product like you see now
days. While I don't deal in HAM radio I do see ShortWave Radio's now and
then ranging from $49 to $100 with very few features that I consider
now to be valuable. State of the Art to me is using the best knowlage
and best use of components at the time rather than cheapest product as
it now is. -- mass production of high speed low quality FET's -- is
today's state of the art for all electronic devices built today.
DSP is great for getting a signal out of noise like a space probe
with a watt or two of power but just what is the front end of the
reciver like? Playing with HI-fi audio I found negitive feedback
is often mis-used. Non-linear components generate x**n harmonics
that creates more noise because nobody considers this anymore.
A valve diode I think is the lowest noise diode but who uses that.
XTAL radio people have great front ends with a high Q but who uses that?
All this aside ham radio still needs good people who know the
equipment rather than some $$$$ product by microsoft-radio-95 so when
ham people need to be called out for real work saving people with radio
they can do it be it state of the art or a old transiver that they just
happen to have kicking around with them at the time.
Allison
KB1GMX
.