Richard Clark wrote:
On Mon, 18 Oct 2004 10:43:03 +0100, "Mark"
wrote:


You know what the trouble is with us amateurs is ?


Hi Mike,

Sure, some of them don't know what "digital" is, your posting contains
examples which follow below.


We are stuck in the analogue age... We should all be using digital
communications by now..


As an isolated statement that is true. There are more modulation
modes now than there were 20, 30, 40, 50 years ago, and many of them
are digital based - BPL is baseband, not modulation, however I will
let that pass for further discussion.
There are also digitally based methods of generating an RF frequency
of a purity that exceeds all the current Ham radio equipment
commercially available, but those methods are not widebanded trash
generators. Clearly, digital methods are not necessarily interfering
methods - except in the hands of commercial interests with less than
amateur talent in marketing dominating their engineer's efforts.

Why aren't we using them then? Is the nasty need for channelizing going
to rear up?


Wasn't there a time when amateurs were ahead of commercial design?


This is called being stuck in the time warp of 1928 innovation and
WWII's need to draft both the Ham and his transmitter because of a
shortfall of equipment. Since then, except for rare achievements like
exploring Spread Spectrum (which the FCC hamstrung) it has been follow
the market.

The Amateur community is not about being a class of inventors, but
rather a resource pool of savvy and experienced technicians and
engineers who could be relied upon to reign in the self-interests of
decadent commercialism. This dialogue is one clear and obvious
example of both that talent's exercise, and the stonewalling of a
crypto-fascist administration.


Now all we do is complain when the commercial world brings out new
technology that causes a problem with our old technology.


I presume by the inclusive nature of "we" that you are against new
technology? If not, then your argument contains its own
self-negation. If so, then your argument is what psychology calls
"projection" WE do not necessarily share YOUR problem.


If there is a digital mode that uses less bandwidth, sounds at least
acceptable to enough people, and allows me to tune my radio in a normal
fashion, I'll hop right on it.

And of course, we have to remember that there is an inertia based on
the need to have people to talk to. If I have the nifty new digital mode
of communications, how much fun is it going to be if I only have three
other people to QSO with? These things take time, and I may assume that
Mark has a digital rig?



Look at the big picture people... We are still using analogue
communications..
Blimey , even my home phone is digital. My CD player is digital, my TV is
digital.


And in this last statement, "we" find your poor understanding of the
problem in general, and the concept of what digital is, in particular.

I guess I hadn't looked at it from that perspective, but I agree, there
must be some confusion as to what exactly digital is.

Your TV is analogue even if your remote tuner is digital. Even there,
your remote tuner is not digital, it is CW (albeit with a different
code set). CW is one of the oldest modes around. That IR beam that
communicates with your big bottle across the room sends a chopped
light beam that is in now way OCTAL nor HEXIDECIMAL but closer to
Baudot. This is about as close to "digital" as you are in the living
room, and Amateur equipment has had this advantage for quite a long
time now (Baudot has been with amateur service for at least 60 years).


As for your home phone or CD player, if you have any impression that
you are actually listening to "digital" you are indeed the product of
genetic manipulation and should rush a sample of your DNA to the
nearest patent office to claim your birthright is actually
intellectual property.

Again, any "digital" property found in these commonplace AND LINEAR
devices is and has been found in Amateur equipment for a very long
time now. If this is news to you, you can then appreciate your unique
problem of "projecting" your lack of understanding on others and
calling them out for being against technology.

I have a nice mid-80's IC745 that is indeed digital in all the places
where it serves the purpose!

- Mike KB3EIA -

On Mon, 18 Oct 2004 13:30:45 -0400, Mike Coslo
wrote:
There are also digitally based methods of generating an RF frequency
of a purity that exceeds all the current Ham radio equipment
commercially available, but those methods are not widebanded trash
generators. Clearly, digital methods are not necessarily interfering
methods - except in the hands of commercial interests with less than
amateur talent in marketing dominating their engineer's efforts.

Why aren't we using them then? Is the nasty need for channelizing going
to rear up?

Hi Mike,

Heavens no. There are several means to generate a clean RF source
digitally. These devices (a chip with a rock) can change phase, or
frequency in the time it takes to change a register (microseconds).
These are largely based on look-up tables feeding D/A converters.

Memory is cheap you may well know, I habitually carry a 128MB flash
drive in my pocket as my briefcase, and a 64MB voice recorder as my
stenographer, and my 32MB Palm Pilot as secretary. Grand total cost
for my "digital" office is under $300.

Another method of high purity RF source generation is direct feed of a
pulse train into amps with only the slightest of filtering. These
pulse trains are weighted to look like a binary sine wave (a few bits
on early, a lot on in the middle, and a few on in the late stage).
This work has been long available in the pages of Steve Ciarcia's
magazine "Circuit Cellar."
http://www.circellar.com/
I believe it was written up by Don Lancaster (a name that should be
resourced for ideas that approach problems obliquely). The length of
the pulse train, and the weighting of the bit positions leads to
exceptionally pure RF (spurs at least 60dB down).

The only problem here in this last method is moving that pulse train
fast enough for HF (128 bit trains to drive at HF will require you to
clock them through at UHF rates).

The only problem with the look-up/ADC method is that with my last look
at these products, they were roughly limited to 16MHz (with 0.1Hz
resolution) - so perhaps some mixing is called for at the higher
bands.

If there is a digital mode that uses less bandwidth, sounds at least
acceptable to enough people, and allows me to tune my radio in a normal
fashion, I'll hop right on it.

You need to look at Digital AM (specifically Harris transmitters).

And of course, we have to remember that there is an inertia based on
the need to have people to talk to. If I have the nifty new digital mode
of communications, how much fun is it going to be if I only have three
other people to QSO with?

This is why Spread Spectrum died in Ham radio. The FCC mandated we
transmit on a specific "gold code" and painted the research into an
isolated technical corner.

I guess I hadn't looked at it from that perspective, but I agree, there
must be some confusion as to what exactly digital is.

It is a Marketing term like fractal antenna - wholly spun from the
imagination to create the impression of advanced technology when it
has been around since the early 1800s (anyone ever here of Ada?).

I have a nice mid-80's IC745 that is indeed digital in all the places
where it serves the purpose!

Exactimundo!

73's
Richard Clark, KB7QHC