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VE2HAR > MT63 09.03.05 05:02l 135 Lines 4120 Bytes #-7500 (0) @ WW
BID : 58754SENTTO
Read: GUEST
Subj: Re: [MT63] MT63 Implementations
Path: DB0FHN<DB0THA<DB0ERF<DB0FBB<DB0IUZ<DB0GOS<DB0EEO<DB0RES<ON0AR<VA2HAR<
VE2HAR
Sent: 050309/0228z @:VE2HAR.#MTL.QC.CAN.NOAM Laval #:40582 $:58754sentto
blandson wrote:
>Hello all,
>
> I am a new member of the group. So I thought I should
>introduce myself before I ask a number of questions. My name is
>Barry and I live in Oregon in the United States. I am also a
>training officer for a radio emergency group here in the
>northwestern United States. Our basic mode is Pactor I. However, a
>number of our members plus changing requirements for
>interoperability with other emergency services, suggest that it is
>time to look for alternatives.
>
> We set up criteria for looking at alternate digital modes.
>Based on those alternatives, MT63 came out on top of the list of
>choices. It appears that MT63 meets all of our requirements except
>one. That is the lack of an ARQ capability. However we have read on
>other venues that this capability is under consideration. We also
>have PACTOR I backup for certain critical interconnections for
>transcontinental communications.
>
>
>
You don't have the proper information Barry. MT63 like Olivia both
use "Forward Error Correction" called FEC for short. This is a hard
thing to envision since it sounds impossible to send a correction in
head of data. But this is done and it's done with math that was never
seen in undergrad collage! The fact of the robustness of MT63 is that
right now in the worst of band conditions I had a 3 way QSO between PA
and MN in the USA and a station in Spain! Signal strength was very low
but the copy was 100% perfect.
Yes Pactor has a hand shake design that allows the receiver to tell
the transmit station I didn't get that. And they repeat until it gets
through or they quit. But Pactor requires a strong signal. I know this
because we share 14109.5 MHz with a major Pactor group. I run 20 watts
to MT63 and I shut them down if I transmit an MT63 CQ message. If I get
an answer we often have a long qso and the Pactor users just have to
wait. I see them trying on my waterfall display but it doesn't work, and
it has NO effect on my 100% copy of the other station.
> There seem to be several MT63 implementations. In our group
>there are a variety of computer operating systems. However, there is
>a desire to standardize on particular implementations so that we can
>more easily support a large widespread audience. This leads me to
>the following questions.
>
>1. Is there a best implementation?
>2. Which implementations are viable back to WIN 95 or WIN 98SE?
>
>
There is a good version from Nino in Italy. It runs well on all
windows versions I guess from win95 up. I forget where you get it but
will find out if you need it. I use Linux and gMFSK is the very finest
device for all digital modes. You can get it from my web page at
www.zianet.com/k5di/ . With gMFSK you can send a ascii file to the
person your connected to and this means a person in LA could send an
important message to a ham in east Texas. He then would call Wash DC and
send the file again to them.
Finally MARS is using nothing but MT63 now for digital radio
communications.
>3. What is the status of ARQ in MT63?
>
>
>
MT63 does not need ARQ and will NEVER have it.
>Thank you very much in advance.
>
>Barry
>AA7ZC
>
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><< Try MT63 on 80m - great fun!>>
>
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