[nos-bbs] Local Emergency communications but able to do e-mail if necessary
KV9U
mrfarm at mwt.net
Wed Feb 14 19:55:24 EST 2007
I agree with some of what you are saying, Demetre. Of course not
completely:)
Appreciate the information on AGW with Airmail2000. I had heard some
time back that the author was going to be including this as a selection
in the list of supported modems. I knew that you could use AGW with
soundcards for packet. Even Multipsk now includes 300 and 1200 baud
packet options.
For a stand alone box, the SCS modems are the best choice at this time
for a hardware solution to high speed HF digital. However we know that
much of this can be done with software as we saw with the SCAMP mode and
we see everyday now with the OFDM based DRM modes (WinDRM, HamPal, etc.).
So it is doable in software providing you have good signals. For weaker
signals you need a fall back mode, even though it won't run as fast. If
SCAMP can run much faster than Pactor 2, and not that much slower than
Pactor 3, although using a wider bandwidth than P2, it seems reasonable
to me that a more adaptable modulation scheme could replace the RDFT
modulation.
PSKmail can compete with P2 and P3 at one level and that is bandwidth.
Several PSKmail signals can operate in the space of one P3 signal. But I
do agree that we need faster modes and it would be OK if wider than the
narrow PSK125.
Based upon the throughput of a basic message, even a throughput of 50
wpm or so is quite adequate for a few messages. Most can not even type
that fast.
Many of us simply will not support a commercial mode on amateur
frequencies that is single sourced and has both hardware and software
totally proprietary.
Did we ever find out what the actual baud rate is of the RFSM2400? Is it
2400 baud or rather a slower rate that has multitiones with a throughput
of 2400 bps?
I agree with Winlink2000 comments. This is excellent for casual use for
e-mail. I do not see it that useful for emergencies in our area because
most of what we do is tactical messaging. We of course do have voice in
place all the time. We have emergency power backed repeater on the
highest point, etc. Of course things can fail. Recently, a local
hospital had their long distance, internet, and cell phones fail due to
a fiber optic cut. The backup was satellite phone. It did not work when
they needed it. It turned out later that the company was repositioning
satellites and the system was not really operational. The only way they
could get a message out was through amateur radio ... which they did.
They had just put the ham gear and antenna in place within the past few
weeks.
In terms of the politics, there must be some system or approach that
appeals to the average user. If you don't have that, it just can not
happen. Politics is not a negative thing as much as it is the art of
what is doable. What can you do that people will support. You can not
force things beyond a certain point. So anything we do has to be
supported by those who make the main decision (which most hams don't
want to make or can not make based upon their knowledge and interest)
but then it also must be supported by the hams who use the system.
Thanks for your comments.
73,
Rick, KV9U
sv1uy wrote:
>Hi Rick,
>
>I have been following this thread with interest and I would like to tell you
>my opinion on this matter.
>
>First of all AGW can work with Airmail2000 provided you download 2 free
>linking programs that allow you to connect AGW with Airmail2000. I have done
>this last week and I can use Airmail2000 with my TH-D7 yes my TH-D7 (using
>Maxframe 1 and PACLEN128) giving me the opportunity to download/upload e-
>mail even with attachments on a 1200bps channel via my TELPAC NODE here in
>Athens. I never had a single crash on my TH-D7 V2.0, early TH-D7s have a big
>problem with KISS mode though.
>
>You can use AGW even with a soundcard for 1200bps and some people have
>claimed success with 9600 bps even depending on the radio they use (i.e. if
>it is a fast switching data radio, 9600 really flies otherwise it is best to
>stick to 1200 bps).
>
>As for PACTOR and SCS well if you really want to get somewhere on HF you
>need the speed and the only fast modem today is the SCS-PTC modems which
>starts from 600 EUROS for PII or 772 EUROS if you want PIII but then again
>PIII is not absolutely necessarry since PII is nearly as fast as a 1200 bps
>packet radio TNC on VHF. And of course PACTOR can be used with Airmail2000
>and JNOS and FBB and in terminal mode with PLUSTERM and with ET4 for file
>transfer. So really all you need is an HF radio, an SCS-PTC controller and a
>cheap laptop. This is only 600 EUROs dearer than an HF radio and a laptop
>and a person that can afford 700 EURO for a cheap HF radio and 600 EURO for
>the cheapest laptop today (I bought a new one for 500 EURO last week) can
>easily afford the extra 600 for an SCS-PTC modem.
>
>Of course there is PSKMAIL that supports ARQ but with PSK125 and an
>effective speed of 100 bps it can hardly compete with PACTOR III at nearly
>5000 bps in a good channel and with its robustness through QRM there is
>nothing, even military modes, that can beat it for effectiveness and
>performance. Really nothing even comes close to PACTOR III. Compare the
>speed difference of the most expensive PACTOR to PSKMAIL is 50:1. If PSKMAIL
>ever manages to support RFSM2400 (which is less than half the speed of
>PACTOR III but not at all as robust as PACTOR III when QRM/QSB/Multipath
>Distortion is present) then we might have some hope but then again RFSM2400
>is not OPENSOURCE at all, which takes it again out of the game. But I
>personally doubt this is ever going to happen since RFSM2400 works in
>Windows and PSKMAIL works in LINUX.
>
>If money is the problem then probably your best bet is to use VOICE ONLY
>emergency comms. Nothing can beat VOICE for simplicity and cost
>effectiveness.
>
>Also, noone is ever going to spend the extra money or time to setup
>something for emergency if he/she does not get anything out of it. And this
>something is at least the satisfaction of using a fairly fast system to
>exchange at least a decent e-mail that he/she can rely on for everyday use
>when there is no emergency. This way one will be trained on how to use such
>a system and this will prove very useful in case of a real emergency since
>the operator will be familiar with the system.
>
>This is definately not something that can only do 100 bps.
>
>As for saving 600-770 EUROS is what one is after then one should better
>stick with VOICE communications which is a lot cheaper since you do not only
>save on the SCS modem but on the laptop too so the saving is at least 1500
>EUROS leaving you with the price of an HF/VHF radio only. One can easily
>serve his/her local community this way.
>
>Airmail2000, JNOS, FBB and many other systems are decentralised systems if
>one wants to use them as decentralised systems but you must find the people
>who are willing to leave their systems switched on 24/7 which is very
>difficult to do.
>
>Only Winlink2000 is not a decentralized system and relies on Internet
>although the guys who support Winlink2000 will assure you for the opposite.
>
>I use Winlink2000 when I am on holidays away from an Internet Cafe and WiFI
>access and I like it very much because it is fast but I am not sure how good
>it can be when Internet goes down, that is why I run two 24/7 JNOS systems
>with HF/VHF/UHF ports here in Athens and not a Winlink2000 PMBO.
>
>Finally I would like to say that it is not only hardware that makes a
>network but the people who make the network. Sometimes politics get in the
>way and people get sick of it, so no PACTOR MODEMS or Computer sound cards
>can save us.
>
>---
>73 de Demetre Valaris - SV1UY
>e-mail: sv1uy at ham.depa.gr
>AX25 PBBS: SV1UY at SV1UY.ATH.GRC.EU
>http://sv1uy.ampr.org/~sv1uy
>http://www.athnet.ampr.org/~sv1uy
>
>
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