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MT-63
is a Forward Error Correcting (FEC) mode for use with
your transceiver and computer's sound card. MT63 seems
to be the (unofficial) emerging sound-card mode of preference for MARS net
traffic. It is considerably faster than AMTOR and clearly more
reliable/error free, particularly under poor conditions. Region One did
some rather extensive testing of this mode and has a presentation of the
results on the national web page; <Navy-Marine Corps MARS MT-63 Info
> Some advantages include; ·
Hookup is easy and inexpensive. (You can even try MT63 with no interface
at all. Click
Here to see how.) ·
MT 63,
especially at 2000Hz, is much faster than AMTOR or Pactor FEC. ·
Works very
well under low power and poor conditions. ·
Very
resistant to interference. (We can
actually send MT63 during a voice communication with solid copy of both the
voice and MT63 by the receiving stations.) ·
Tuning is not
critical. Within 100Hz seems to work
fine. · IZ8BLY MT63 Freeware is available for DOWNLOAD (For a copy of the older version with
the camera Icon request it from NNN0TJC
)
·
Setup is
easy. Click Here
for step-by-step instructions. Disadvantages include: ·
This is NOT a
linked (ARQ) mode. AMTOR or PACTOR is
still needed for access to the MARS Data System (MDS). ·
This program
requires a computer with a Pentium 166MHz or faster processor. (If your computer is slower, Click Here
for possible fix. ·
MT63 requires
fairly accurate sound-card clock speed.
If you have trouble copying MT63, click
here for steps to calibrate your soundcard. |
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Set-up Instructions for IZ8BLY
MT63 Terminal STEP-BY-STEP here’s all you need
to do; 1.
Download the MT63 freeware from DOWNLOAD 7.
Make sure the 'Paper' button is on to receive. When you see the
received signal (on the right hand side of the screen), adjust your VFO to
place it between the blue lines. (A little off does not seem to be a
problem.) (If you are on frequency in SSB mode, you should not have to
tune at all.) (Your precise frequency offset is shown down at the bottom of
the screen) 8.
That’s it. You will hear/see the signal
well before the text starts printing, and it will continue to print after the
signal stops. Don’t worry, that’s just the program doing
its thing. (Sending stations should send
a long enough idle to allow you to tune if needed.) If you have a slower machine, or it may not work right. Click here
for a possible remedy. (For me MixW
worked on a P166 computer, but I had to apply this remedy to use the IZ8BLY
software on it.) If
you want to get a feel for MT63, change mode to 1000Hz bandwidth/long
interleave and tune to 14109.5 USB. You may have to wait for a while,
but sooner or later you should copy someone’s CQ. If you are already
set up to transmit PSK/AMTOR or other soundcard modes, go ahead and answer
the CQ, or send your own. You’ll enjoy this mode. There
are various ways to transmit MT63 (using IZ8BLY MT63 Terminal). ·
Key F12. (Key F12 again to end transmission at the
end of the buffered text. ·
Just begin
typing in the TX window. If you want
to type ahead for later transmission, type in an "*" and then your
text. Control-T sends the type-ahead
text. ·
Click on
'Transmit' on the tool bar and select item needed. When
sending a text file you should hit F12 to start transmitting an idle signal,
and then go to 'Transmit'/'Send Text File' to select the file to be
sent. By starting transmit first, the
receiving stations will have time to synch to your signal. If you just click on the file and begin to
send immediately you may not allow time enough for all stations to
synchronize. This can cause the first
part of the message to be missed. First
time users of soundcard digital programs seem to have the most difficulty
with Sound
Card Settings. Chick
here for instructions on setting up your soundcard. IZ8BLY' software has
a concise well written help file which is well worth the time to read. |
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If
you are having difficulty copying MT63, your soundcard clock frequency may be
slightly off. Don’t shoot your
computer, you can compensate for this by adjusting the MT63 sample rate. Here’s how; 1. Download MMSSTV (an
excellent freeware Slow Scan TV program) from http://www.qsl.net/mmhamsoft/mmsstv/ 2. Install and open MMSSTV. 3. In MMSSTV, go to Option,
Setup MMSSTV, Misc page, and click Adj button in the ‘Clock’ box. 4. Tune your radio to WWV. 5. Tune into the tick sound. 6. Continue listening to the
sound for a while. You will have a
vertical line. 7. Click the upper point of
the line. 8. Click the lower point of
the line. 9. You have now calibrated
the MMSSTV software. (Please note
that this did not change anything on the soundcard, only in the
software.) Make a note of the
frequency that is now displayed in the box. 10. Close MMSSTV and open the IZ8BLY MT63 Terminal. 11. Divide the frequency from #9 by 11,025 and applying the resulting
factor to 8000 Hz.) (Example: 11037/11025 = 1.00109. 8000 x 1.00109 = 8008.7) 12. Click on File/Preferences/General and then type this frequency into
the ‘Sample Rate’ box. By the way, you just added
Slow Scan TV capability to your station.
Open MMSSTV, tune your radio to 14230 and watch the images start
rolling in. Who says there is no free
lunch? If you want to know more
about SSTV, start at this site…. http://www.qsl.net/mmhamsoft/mmsstv/primer.htm
or SSTV for
Alabama NAVMARCORMARS |
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There are various ways to
capture text received by the IZ8BLY MT63 Terminal. - First, we recommend turning on the automatic capture
option. This will allow you to
capture and later retrieve all received and sent text for the session. This is accomplished by clicking on
'Receive' (at the top of the screen)
then clicking on 'Log to File' in the drop down box. This feature will remain on (checked) for future sessions
until you turn it off. Each new
session appends the new received and transmitted text to the file. The file is named 'mt63log.txt' and is in the sub-folder
where you loaded the program. It can
be opened with Notepad or any text
editor. Use normal Windows
routines of copy and paste to place in another file which may, in turn, be edited and printed etc. - In the receive window, you can highlight text you wish to
copy, and then click on the camera icon to place in your system's
clipboard, then paste it into
another text file. Clicking on the
icon to the right of the camera icon, pastes text from the clipboard to the TX buffer. Text will be
"quoted" by adding a ">" character at beginning of
each line, as is done in e-mails. This feature is useful for repeating what
has written by another radio operator (e.g. in a net, when stations don't copy each other). If you are using a version
without a camera, see MT-63 Tips. |
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Try MT63 With No Interface MT63
receive works well even with no interface at all. To Receive, just put your computer microphone in the vicinity
of your radio speaker. To Transmit,
just hold your radio microphone near (but far enough away so you get little
or no ALC reading on your meter) your computer speaker. This is not the recommended method to
transmit, but with a little practice, but it does works. We
have one member who's computer is away from his operating location. He has successfully tape recorded the
received MT63 signal and played it back to his computer for perfect copy. He reverses the process to send a file. |
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Use the MASTER control to adjust the sound
to the PC speakers (if you use them) and then re-adjust the other levels as
needed. Note that other windows applications you run on your PC that provide sound
card adjustment controls may change your settings! You may have to re-adjust
these levels. Generally, once these levels have been set, you will not need to change them.
Adjust the sound card audio OUTPUT level to the
transceiver such that a small amount of ALC voltage is detected at the
transceiver while transmitting into a proper antenna load (50 ohms) with the
MIC Gain control at a nominal setting. After this adjustment, you can reduce
the MIC gain control slightly to achieve full output
power with no ALC deflection. You'll probably find that the transmitter
output seems a little low, and you may want a higher transmit audio level -
but don't overdo it, as linearity is highly important. There should be no ALC
activity indicated (NONE AT ALL) and an indicated output of 25W is entirely
appropriate, as the average 100W rig won't provide linear performance with
much more power. Remember that MT63 consists of 64 sinewave signals all at
once, (very high peak to average ratio) and linearity is paramount. Remember
that any station you can work with 100W of RTTY can be worked with 1W of MT63
(and probably still be better copy!) Several of the software packages help files
have good detailed instructions on sound card tuning. There are many
approaches to this, as you will see, but just remember that once you have
found settings that work for you they should work with any of the programs.
Speech
processors should be OFF.
Here's a little utility program that's a "MUST HAVE"! It allows you to store and retrieve your sound card settings, avoiding the process of readjusting each time another program changes them. QuickMix is freeware and can be downloaded from here. |
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If
your computer is too slow to run MT63 Terminal please open the file IZ8BLY.INI
and add/modify the following lines: BlockLenMultipler=1 WaterfallEnabled=on First
try with values up to 20 of the "BlockLenMultipler", this will make
the waterfall flicker more but is less CPU intensive. If still does not work
try "WaterfallEnabled=off" which will completely skip the plot of
the waterfall display. You can still use the "offset" information
reported on the status bar for a perfect tuning.
As you will not
have a waterfall to view, you can go to another soundcard program that works
on your computer, such as Digipan or any PSK
program, tune to 14070.0KHz, and adjust your soundcard for PSK31. Remember your settings or save them using QuickMix. These settings will work fine for MT63. |