software I use is the highly popular MMSTV by Mako Mori. The
software is free and runs in Windows, using the PC soundcard for SSTV
input and output. The software supports
all the common SSTV modes such as Martin, Scottie, and Robot.
MMSSTV also includes more specialised systems such as
high definition, and experimental narrow bandwidth modes.
The image below is an
example of four SSTV pictures I received during a QSO with YO2MFZ
Each picture is 320 x
256 pixels - not
high quality but a good trade-off between picture resolution and
mentioned above, higher resolution SSTV modes
are supported by MMSSTV but they are rarely used.
Martin 1 and Martin 2 modes are usually used by European stations and
Scottie 1 and Scottie 2 are used by North American and Asian stations.
It doesn't really matter which you use as long as you use the
same mode as the other station(s) in your QSO - this is basic SSTV
multipath conditions Martin and Scottie modes do not perform well so it
is better to use the MP or SC2 modes on 80m at night. SC2 120
and SC2 180 are the most popular multipath tolerant modes.
The images below were received on 80m within a few minutes of each
other over the same path. Ignoring the noisy lines - probably due
to QSB - it can be seen that the SC2 180 image has good vertical
synchronisation and no herringbone pattern unlike the Scottie 2 image.
Due to the small size of the WARC bands (30m, 17m and 12m) narrow bandwidth SSTV (N-SSTV) is recommended for use on those bands.
SSTV frequencies in Europe are 3.730MHz, 7.165, 14.224 to
14.239MHz, 21.334 to 21.346MHz, 28.680MHz +/-. SSTV
has also been heard at the top end of 20m and 17m. Sadly the
3.781MHz daily SSTV weather net has moved to DRM and the
pictures have a fuzziness caused by excessive .jp2 compression. On
HF, SSTV should be transmitted in LSB on frequencies below 10MHz and in
USB above 10MHz - the same as voice. On 2m frequencies between
144.500 and 144.600MHz FM are used in UK and can be quite busy at times
in the English Midlands.
The latest version of MMSSTV can be downloaded from
the web site HERE.
N-SSTV Group (Narrow SSTV) web site HERE and on Facebook.
SSTV Operating Tips:
1. Do not transmit half or part
pictures - annoying!
2. Spread out - don't all try to have a QSO on the same frequency! Use 1.5kHz or 3kHz spacing.
Click HERE for more information.
3. Respect digital users
(FreeDV, DRM, etc) - don't cause QRM just because you can't decode
4. Do not ragchew - the SSTV frequency area is for TV, not rag chewing.
Short comments are acceptable though.
there is an SSB contest try the top end of the band or even the WARC
6. Do not transmit pictures that will offend other people.
7. ...and finally.....
SSTV pictures are caused by differences between sound card clocks.
The sound card's sample rate may be quoted at 11025Hz but
will not be the case. In an attempt to resolve this problem
MMSSTV incorporates automatic slant adjustment. This works to
degree but if the slant is too great because the sound card clock is
way off frequency then MMSSTV can't decide which SSTV mode is in
use and the received and transmitted pictures are ruined. It
is better to correct your sound card frequency rather than rely on
automatic slant adjustment! All it takes are some software
MMSSTV is probably the
most popular SSTV
program out there and is also the biggest cause of the slant problem so
I will attempt to give a basic guide on how to correct your sound card.
All settings are in MMSTV.
on 'Option' then
click on 'Setup MMSSTV'. Click on the 'Misc' tab and a window
should appear similar to the one shown below.
irrelevant options have been blurred out to avoid confusion.
will see in the image above that the Clock has a frequency value and
there is also a TX offset. Believe it or not some sound cards
have slightly different output and input frequencies!
will set the receive (input) frequency of your sound card.
on 'Adj' and another window will appear. Tune your receiver
time station. In Europe RWM is really strong. Tune
4.995MHz USB, 4.997MHz LSB, 9.995MHz USB or 9.997MHz LSB. You
should be able to hear some 1kHz pips transmitted by RWM. If
hear a steady tone or CW then wait a few minutes and the pips should
start. Make sure your receiver is connected to your PC's
or Microphone socket.
After a short time a trace of
should appear in the window. These marks are the pips as
from RWM and should form a vertical line as shown below.
lines may not be as slanted as the those above or may even be slanted
the opposite way - do not worry. When you have a good line of
white click at the lower end of the white line preferably on the left
or right edge of it. A thin line should appear which moves
the mouse pointer. Now click at the upper end of the white
so the thin line follows the same angle. Click on 'OK', the
window will disappear and the Clock frequency will have changed.
click Adj again and expand the calibration window to full screen and
repeat the above process. Making the window bigger helps you
an accurate line. You will notice that the slant is less
Once you are happy that the received pips form a vertical
the calibration window click 'OK'. The sound card input
is now calibrated.
Now it is time to calibrate the
sound card output! Click on the 'TX' tab to show the window
'Loop back' click on 'External (full-duplex)'. This means
your sound card's input and output will work at the same time.
Click 'OK' to take you back to the main MMSSTV window.
Connect you sound card's output to its input using a suitable
lead, i.e. Headphones to either Microphone or Line-in.
select Martin 1 as your TX Mode and click 'TX' so that you are in
effect sending an SSTV picture back to your own computer.
the picture has been sent click on the 'Sync' tab as shown below.
In this example I sent a blank picture just to make the sync
You may notice that the sync
lines are not vertical at all. Even if they are vertical go
through these steps anyway.
Click on the yellow
smiley face button and the sync lines should become vertical as shown
click on the 'TX' button which is to the right of the 'Mem' button.
Your TX offset is now set. Just go back into
'Setup MMSSTV' then click on the 'TX' tab to set your Loop back setting
to OFF. Your sound card is now calibrated to transmit good
Now you have calibrated your
sound card you
will transmit nice vertical images but you may still receive slanted
images. This is due to the other station not having set his
card up properly. So until the entire SSTV fraternity have
educated in slant-free SSTV, use the MMSSTV automatic slant correction
and tell the other station they have SLANT!