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Re: Going Digital... Ham Radio?




Actually, I disagree completely with Jon-- I think you are going to
see radios in general turning into digital systems, even for analog
modes.  We are at the point that DSP devices are cheaper than things
like mechanical filters-- and have a lower board real estate and component 
count than analog IFs.  Very shortly A to D technology will
catch up with the requirements for RF, and at that point the DSP
will be able to be done at RF directly and the current A/D dynamic
range limits should be resolved in a couple of years as well.

Just because it is "simple" to use existing modes that should not
preclude us trying to develop more modern modes.  Packet radio died
because of the prevelance of the Internet and apathy.

"New" ham modes such as Charles Brain's Digital voice would be an
absolute shoe in on 3D-- and should be encouraged on the birds.

Not all new technology need be expensive and "broadband highspeed"--
take a look at PSK31 for example.  Its pratically FREE and it is a
super mode made with the appropriate engineering tradeoffs for its
intended use on HF.  It wouldn't be all that good with doppler on the
sats, but a mode like this could be developed for sats as well--
at a cost of time, but not equipment.  The NOT EQUIPMENT is the
advantage of DSP.  That is why the software is complicated.  The system IS 
the software.  This is NOT a bad thing.

73,

Fred Spinner, W0FMS


>From: "Jon Ogden" <jono@enteract.com>
>To: "Tony Langdon" <tlangdon@atctraining.com.au>,        "'Bob Bruninga'" 
><bruninga@nadn.navy.mil>, <amsat-bb@AMSAT.Org>
>Subject: Re: [amsat-bb] Going Digital... Ham Radio?
>Date: Wed, 7 Jun 2000 11:29:07 -0500
>
>
> > > Packet Radio Affectionados,
> > >
> > >    We have had packet radio for 22 years and yet we are
> > > seeing a decline
> > > of digital operations on HAM radio (with some exceptions) at
> > > the same time
> > > that we are seeing an Explosion of Wireless digital
> > > applications in the
> > > consumer market.
> >
>
>A big reason:  $$$$$$ and capacity issues.  If there was enough spectrum
>capacity for all users with an analog system, then there wouldn't be any
>digital stuff going on.
>
> > It is the same story here.  Terrestrial packet radio has declined down
>here.
> > Most likely causes are due to performance (lack of) and the 
>proliferation
>of
> > the Internet.
>
>Well, probably because the average price of a high speed TNC is something
>the average ham can't afford, let alone the quality of radio needed to use
>it.  Even at 9600 baud, we are still way behind the speed curve in
>comparison to terrestrial wire-line based speeds.
>
>BUT WHO CARES!
>
>Ham radio is about communication.  WHO CARES if it is digital, analog or
>both.  It really makes no difference.  Analog is still alive and well in 
>the
>commercial/consumer arena.  Did you make a phone call today?  Well, unless
>your home or company uses a digital PBX, ISDN or DSL line you used an 
>ANALOG
>system.  And an analog system based on old, old, old standards.  Shame on
>the phone company for using such outdated technology.  Why, they aren't on
>the cuttting edge of things.  How can normal telephone service survive if 
>it
>doesn't go digital?
>
>These are the same shames that are forced on ham radio operators.  So if
>analog won't work for us, how will it ever work for the phone companies?
>
>Additionally, the complexity and cost of modern digital systems is 
>enormous.
>Sure, your cell phone is cheap, but the infrastructure equipment used to
>talk to it isn't.  The amount of software is truly mindblowing.  In your
>major RF communications companies today you probably have 5 software
>engineers to every hardware engineer.  Are we as hams prepared to build
>radios that have 12 MB of code in them just so we can "be on the cutting
>edge" and "have the latest digital technology"?  Plus, the amount of error
>correction, handshaking, etc. that goes on in most of the systems is quite
>sophisticated and does not really match up well to ham radio.  For example,
>most SMR (even analog) sytems these days use trunking technology.  Ham 
>radio
>doesn't.  Why?  Well, because it doesn't fit the rules given to us by the
>FCC for frequency use, etc.  Additionally, it's too complex and to 
>difficult
>to set up to allow anyone to use at any time.
>
>High speed digital modulation techniques require very linear transmitters
>(in most cases).  A 50 watt mobile with a class A amplifier just so that 
>you
>can use the latest whiz-bang digital modulation isn't practical!
>
>Modern digital communications is tremendously more than AX.25 packets.
>
>If people want to explore digital technology then that's fine.  More power
>to you.  Develop the latest and greatest modulation scheme.  Go after it,
>experiment, innovate.  If that's what you want to do, fine.
>
>Digital communications hasn't caught on with ham radio because it isn't
>needed.  The technology we have in place now works fine for the majority of
>folks.  They don't need anything else to communicate with people world 
>wide.
>Ham radio is fun.  It's a hobby.  We have a hard enough time teach 
>appliance
>operators in our hobby how to solder wires and build antennas.  It would be
>even more difficult to get them to develop digital stuff.
>
>Again, digital has its place, but it never will be the end all and be all 
>of
>ham radio.  I am interested in it.  I am active on APRS for one thing.  
>It's
>great.  It has a good purpose.  I am interested in PanSAT if it ever gets
>turned over to us.  I think have a spread spectrum satellite would be very
>interesting and I would probably buy or build the equipment to use it.
>
>Let's not just think in the box of "purely analog" nor in the box of 
>"purely
>digital", but let's use whatever communication mode is best suited to the
>purpose we want to use.  After all, newer is not necessarily better.  Gun
>powder has been around for hundreds if not thousands of years (the most
>technologically advanced space craft in the world uses rockets based on
>ancient solid powder technology - and so does the Ariane V that will launch
>P3D!); the light bulb is over 100 years old; penecillin is old, yet it 
>still
>is used to treat diseases.  Just because technology is old doesn't make it
>bad and just cause it's new doesn't make it good.
>
>OK, back to satellites.
>
>73,
>
>Jon
>NA9D
>
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