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ZL3AI > APRDIG 27.10.06 05:39l 122 Lines 4062 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 28 #12, 4/4
Path: DB0FHN<DB0MRW<DB0SON<DB0SIF<DB0EA<DB0RES<DK0WUE<SP7MGD<CE8FGC<ZL2BAU
Sent: 061027/0421Z @:ZL2BAU.#87.NZL.OC #:11510 [Waimate] $:8898-ZL3AI
From: ZL3AI@ZL2BAU.#87.NZL.OC
To : APRDIG@WW
Message: 24
Date: Fri, 13 Oct 2006 02:26:24 +1000
From: "Andrew Rich" <vk4tec_at_tech-software.net>
Subject: RE: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
I have tried UHF 9600 and VHF 1200.
VHF 1200 always seems to have a better hit rate.
UHF seems to be prone to flutter alot more.
Is that because of the wavelength ?
Andy
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec_at_tech-software.net <mailto:vk4tec_at_tech-software.net>
web: http://www.tech-software.net
Brisbane AUSTRALIA
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Message: 25
Date: Thu, 12 Oct 2006 12:27:25 -0400 (EDT)
From: Rick Green <rtg_at_aapsc.com>
Subject: Re: [aprssig] Bandwidth IS THE FUTURE OF APRS
On Thu, 12 Oct 2006, wa7nwp wrote:
>>>I do agree that the above beacon is
>>absolutely wasteful of bandwidth!
>
>We have to change the way we look at things.
>
>YouTube feeds 100 MILLION!!! Videos a day. Those Videos are in Megabytes.
>(You all saw the dramatic 4th episode of Chad Vader - right?)
Yes, and it feeds it over fiber, on clean point-to-point links, without
CSMA issues, not to mention hidden-transmitter issues, etc.
Also, YouTube, and other video-on-demand sites, as well as various
IP-streaming audio and video sites, are themselves bandwidth-limited, in
that separate bandwidth is needed for each simultaneous user. Traditional
RF broadcasting is much more appropriate for mass distribution of media.
>It's 2006. We're still running 1200 baud (nope - didn't forget the K at the
>end of that -- hard to believe.) We panic if somebody actually adds an
>extra hop to their path. Here we're counting fraking bytes in a status
>packet.
Because on a 1200baud radio channel, those bytes matter.
>We have incredible technology just waiting to be put to use. We have dozens
>of vastly underused channels. We probably have Megabytes in the Microwave
>spectrum that's dead dead dead.
We DON't have the technology sufficiently developed. My meager
experiments with 9600 baud told me it's extremely difficult to keep a
single link up over a 20-mile path using directional antennas. The
sensitivity of these modems to frequency stability, seleective fading,
etc., tells me we're a long way from practical mobile high-speed packet.
We could adopt the techniques that are being implemented by the digital
cellular carriers for high-speed mobile digital transmission, but many of
those are patent-encumbred, so we have to start from scratch and develop
our own.
>Lets work on moving on - not digging a deeper hole then what we already have.
Agreed, but from where we're at, the development needs to happen first
on building a stable high-speed backbone. Unstable mobile stations will
come later.
>Quiet air is wasted air - make packets!
This sounds to me like the same kind of attitude that's got our roads
clogged with inefficient, gas-guzzling SUV's, and our children killed
trying to secure the oil to fuel them.
I plea for appropriate use of the technology at hand, and careful
adoption of newer technologies that are actually better, not just bigger
for the sake of our egos.
--
Rick Green, N8BJX
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-Benjamin Franklin
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Message: 26
Date: Thu, 12 Oct 2006 18:43:33 +0200
From: "Jan T. Pharo" <la2bba_at_jpharo.net>
Subject: Re: [aprssig] Who had the Garmin or Deluo Serial GPS OT
"Alan P. Biddle" <APBIDDLE_at_MAILAPS.ORG>, Thu, 12 Oct 2006 16:00:05
-0000:
>I received several messages in this thread with the actual subject of: RE:
>[SPAM] [aprssig]
(snip)
>I had to rescue them from my SPAM folder, and wonder how they got so tagged?
I had them too. They were marked [SPAM] before they got to my
Mailwasher filter.
--
73 de Jan, LA2BBA
Hvaler, Norway
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End of aprssig Digest, Vol 28, Issue 12
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