[CALV-AUXCOMM] Fwd: Digital Mode Software Downloads

Wed Nov 24 00:03:55 EST 2021

Shawn,
Did you receive and forward my Nov 10 email asking for operators for the Jan 6 Hospital Drill? Thanks.

tnx es 73, deJimWB3KASPRGE ARES ECMDC SEC wb3kas at arrl.net

-----Original Message-----
From: Shawn Donley <n3ae at comcast.net>
To: ARES Reflector <calv-ares at mailman.qth.net>
Sent: Wed, Nov 17, 2021 1:49 pm
Subject: [CALV-AUXCOMM] Fwd: Digital Mode Software Downloads

If you missed the Calvert AUXCOMM net last night, we're planning on doing some digital mode practice in the near future.  Since we have several new members, the info below is to get them up to speed. 

Looking towards practicing Winlink, MT63 and old style AX-25 packet.

N3AE
Calvert EC

>    ---------- Original Message ----------
>    From: Shawn Donley <n3ae at comcast.net>
> 
>    Subject: Digital Mode Software Downloads
> 
> 
>    All,
> 
>    As promised during tonight's AUXCOM net, here's the links for downloading software for some digital modes.
> 
>    If you're having problems, give me a call (240-298-3115) and I'll try to help.  The info below is a top level summary of what's needed to run the modes shown.
> 
>    A quick note... these digital modes over a radio (HF or VHF) are a LOT slower than your internet connection.  Don't expect to send long messages or big attachments.  For example, on 2M Winlink, this email with its attachments would probably take 10 minutes to send via a Winlink gateway station.
> 
>    ------------------------------------------------------------------------------------------------------------------
>    Winlink 2000
> 
>    Software download at https://downloads.winlink.org/User%20Programs/
> 
>    Download the software installation instructions and Winlink Express Install.zip
> 
>    Winlink is the de facto EMCOM digital mode for our ARRL section.  Its origins come from the desire for blue water sailors to have some means of sending and receiving short emails via HF.  Winlink messages can be sent to destination stations identified by their callsign or even to an internet email address.  It's also possible to send messages by radio-only between two stations by using a peer-to-peer (P2P) session.  One disadvantage of Winlink is that third parties cannot easily copy a message being exchanged by two other stations over the air.  This leads to some loss of situational awareness during an emergency.
> 
>    Winlink requires a Terminal Node Controller (TNC) for operation on VHF and UHF (Packet Winlink session & Packet P2P session) , and a sound card interface for operation on HF (Ardop session & Ardop P2P session).  The Winlink Express software also provides a means to send and receive messages over the internet (TELNET session) so it's still possible to "play" before you have a radio and TNC set up.
> 
>    The latest session type recently added is VARA (VARA HF Winlink, VARA FM Winlink, VARA HF P2P and VARA FM P2P.  VARA requires downloading and installing third party software that requires purchase of a license.  For the moment, we'll skip that.  But VARA has demonstrated a much faster message rate than other modes, so eventually we may need to take a look.
> 
>    If you already have a sound card and a fairly new computer, it's possible to use a software package to emulate the hardware TNC.  I've never tried that myself but some folks might want to give that a try.  See https://packet-radio.net/direwolf/
> 
>    -----------------------------------------------------------------------------------------------------------------
>    MT-63
> 
>    Software download at http://www.w1hkj.com/ or https://sourceforge.net/projects/fldigi/
> 
>    Download FLDIGI, FLRIG and FLMSG along with their user manuals
> 
>    The FLDIGI software includes a vast number of different digital modes including PSK-31 which was one of the most popular HF digital modes before FT8 was released.  The mode of interest for EMCOM is MT63 which comes in several flavors with different bandwidths and corresponding different messaging speeds.  The MT63 modem uses strong forward error correction so unless conditions are really bad, you will see perfect copy with no errors.  Unlike Winlink, third party stations can receive and copy messages.  MT63 is primarily a radio-only mode and does not rely on the Internet.  We have successfully used it locally on HF, VHF, UHF and even via our 146.985 voice repeater (yes, it can be sent through a voice repeater if needed).
> 
>    Because of bandwidth restrictions imposed by the FCC, we're limited to MT63-1000L on 10 meters.  MT63-200L can be used on 2M and up.  MT63 is also used as the "core engine" in several EMCOM packages including the Narrow Band Emergency Messaging System (NBEMS) and Outpost (Google for info).
> 
>    MT63 requires a sound card interface between your radio and the computer but in a pinch it's possible to copy MT63 by holding the computer microphone up to the radio speaker, and send MT63 by holding the radio's microphone up to the computer's speaker.
> 
>    ---------------------------------------------------------------------------------------------------------------
>    AX-25 Packet
> 
>    Old fashion AX-25 packet just requires some sort of terminal program like Putty and a TNC, or TNC emulation software and a sound card.  Plain old AX-25 packet can be used between two station (actually more than two with multi-connect) with guaranteed good copy.  Each "packet" includes check sum data and if the receiving station decodes the message but has the wrong checksum, a request to re-send is issued.  So in good paths, this works fine.  If the path is not the best, there can be a lot of "retries" and possibly a disconnect of link if the retry limit is reached.
> 
>    It's also possible to send packets without being "connected" to another station, called unproto mode.  If there's a group of stations with good paths between them, it's possible to have a digital round table by operating in the unproto mode.  A digipeater can be sued to stretch distances in both the AX-25 "connected" mode and the unproto mode.
> 
>    ------------------------------------------------------------------------------------------------------------------
>    Our local digipeater
> 
>    We have a 2M digipeater on the state highway tower in Prince Frederick.  The callsign is K3CAL-1 on 145.750 MHz.  This digipeater can be used to reach one of the area Winlink "gateway" stations that move Winlink messages onto and off of the Internet.  The digi can also be used with AX-25 packet.
> 
>    In the longer term, we're hoping to put up our own Winlink gateway station at Mt Hope.
> 
>    ------------------------------------------------------------------------------------------------------------------
>    Other info
> 
>    I've attached a document describing MT63 and another document with web links of interest.
> 
> 
>    Have fun
> 
>    N3AE
> 
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