4 Nov
2005
4 Nov
'05
5:09 p.m.
Hmm... There
are plenty of books on making simple valve radios still
being written and sold (I bought a couple last week). OH, it's a small
market, but somebody other than myself must find it interesting.
I should not write postings multi-threaded :-( The argument actually
mixes up two ideas; the first is that an AM
detector is too mediocre to most people nowadays who are accustomed to
FM stereo sound or even 5.1/6.1/7.1/whatever sound even with cheapest
receivers. The second
point emphasizes on the "digitalization" issue:
in the near future there won't be any analogue AM or FM
transmissions/transmitters any more; even SW band migrates
THis ia a great pity, and actually, given the number of cheap radios
around, I wonder if it will ever happen. I can't believe the public will
accept having to replace doxens of sets.
Of course. Building some gadget from a kit is just
part of learning the
usage of the tools. I did this in the very beginning,
as almost every newbie, but after a while changed to own experiments.
I do still occasionally build kits. I do it if I want the end result, and
by building the kit (a) I know it's been built properly and (b) I get a
schematic. For example by bench PSU was built from a kit. Yes, I could
design one, but actually, the kit was no more expensive than buying the
bits separately.
Unfortunately, many of the more interesting TTLs are
now no longer
easily available (you find lots of octal
drivers and registers, but almost none of ALUs, multifunction chips,
RAMs - even the classical
7490,7491,7492,7493 combo of counters for any purpose is reduced to
7490/7493 - noone
needs to divide by 6 ('92) any more - you don't build digital clocks in
TTL) - you have to seek for
them in specialized mail-order shops. This is no issue for us old farts
who play with such stuff for
long time, but it is another hurdle for starters. A kit with all parts
is much easier to acquire - but then,
Waht somebody needs to do (and it can't be me for obvious reasons) is to
select some CPLDs/FPGAs where the download protocol is documented (that
is, you can progam the chip, given the binary file, without a proprietary
programmer), and use the tools (that's why it can't be me) to make some
useful logic functions -- things like an <n> bit universal shift
register, <n> bit ALU, counters, even JK flip-flops, gates, etc. Make the
binary files available for free download.
Anyone wanting to experiment with logic and not wanting to use the
horrible CAD tools under an even worse OS, can then program up some chips
with the appropriate files and use the resulting devices like the TTL of old.
-tony