In article , "Phil Kane"
writes:
On 8 Aug 2003 10:12:11 -0700, N2EY wrote:
AMTOR is pretty much dead, I am told.
Certainly not as popular as it once was, but I don't think it's entirely
"dead."
How many HF amateur AMTOR contacts have you or anyone you know made in
the past year?
Yet SITOR - the commercial version of AMTOR - is the standard HF
mode of data communication in the maritime service. That, and not
obscenenly-expensive satellite comms, is what killed maritime CW.
Wasn't maritime MF Morse capability mandatory until the satellite based
distress system came online?
The ship's purser or deck officers can pull up the preset HF
transceiver channel and pound away, and even personal e-mail is now
sent and received by a SITOR connection to AOL via Globe Wireless,
the successor to RCA and ITT, via an AOL "kiosk" in the recreation
areas. No Radio Officer needed.
Sure. And the reason all that happened was that the shipping companies decided
to make the inital investment in SITOR equipment, and pay for it with the
salaries of the laid-off radio officers. And as long as the SITOR equipment
does the job and costs less per year, there will be no reason to replace it
with something better.
One of the San Francisco area marine radio techs, a ham, applied to
the FCC to be able to offer PACTOR service in the marine bands, and
after consulation with the ITU, his request was turned down because
it was not an international standard and would not give that much
improvement over SITOR considering the changes necessary.
Exactly - the improvement was judged to be not worth the investment. Since
decisions like this are made at the top and conformity is deemed more important
than what people *want* to do, the existing system is kept.
Which is why you can watch a 2003 TV show on a 50+ year old TV receiver. NTSC,
anyway.
And the US Coast Guard and other similar agencies world-wide
continue to transmit NAVTEX bulletins (marine broadcasts) on 518 kHz
worldwide using SITOR.
Using a system that is almost completely automated.
Of course what really drove all that was PC/soundcard setups becoming
affordable.
Agreed ... multimode with a std SSB radio and PC ... cool stuff.
Yeah - I can tune SITOR by setting the (suppressed) carrier 2.2 kHz
higher than the channel center and using LSB. Cheapie "FSK".
Going to be "more easier" later on this week when my new Ten-Tec
computer-tuned DSP HF receiver arrives, and I can set the filtering
to just where I want it.
bwaahaahaa
I'm not throwing my AMTOR/SITOR TNCs away just yet.
But how much AMTOR will be found in the HF ham bands today? I daresay not much.
In fact you'll probably find more 60 wpm Baudot RTTY on the ham bands in the
course of a year than you will find AMTOR. (if you count contests).
Sort of. But it's actually a patch job.
One reason packet is stuck at 1200 baud all these years is because
going faster would require a purpose-built data radio. Ikensu isn't
going to do it unless there's a proven market, and the failure of 9600
to get much attention means they will wait some more.
Hey, we know that we can get at least 28K or more in a standard
audio channel.
Sure - if the channel's characteristics are good enough.
There's also the question of what FCC will allow in symbol rate and such.
But hams are cheap - nobody (including me) wants
to throw away existing 1200 baud radios and TNCs that work really
well for the type of canned messages that we get on packet, unless
they are super-whizzes at Qualcom, with due appolgies to Phil Karn
who fits that description and has done a LOT for digital ham radio
specifically and whom I admire greatly.
I disagree with hams being "cheap". It's more a matter of not being able to
write off expenditures. Businesses can depreciate equipment - hams can't. They
can also pay for equipment out of reduced labor and repair cost - hams can't.
Engineering economics 101.
73 de Jim, N2EY
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