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A Guide to MMSSTV
This is a guide to using the program MMSSTV.
This can be downloaded from here.
SSTV (Slow Scan TeleVision) is most common on the HF (High-Frequency) bands [3-30 MHz] but is sometimes used on 2meter (ISS [International Space Station] SSTV events) and other bands.
Frequencies:
80m: 3.735Mhz LSB (Lower SideBand)
40m 7.165Mhz LSB
20m 14.230Mhz USB (Upper SideBand)
2m
144.500Mhz FM (Frequency Modulation)
145.800Mhz FM (ISS Downlink)
For help on receiving Satellite signals, see here.
70cm 432.500Mhz (Rare in my area)
Modes:
Martin 1 (Popular in Europe)
Scottie 1 (Popular in USA)
PD120 (Used on ISS transmissions)
What does SSTV Sound Like
Below is a selection of SSTV recordings (from VE5KC) which you can test decoding with MMSSTV by setting the audio input, discussed below, to a microphone, by using a Virtual Audio Cable or the stereo mix of your sound card.
The Software:
Audio Setup
MMSSTV is a popular piece of software used for the sending and receiving of SSTV.
For a simple receive setup all you need to do is connect the headphone out of your radio to the input (mic or line) of your PC.
For transmission you can get a dedicated data modes cable etc. made specifically for your radio. Or, you can build you own cable, which connects from your headphone out of your PC to the Microphone socket on your radio. The PTT (Pust-To-Talk) can then be done using VOX (Voice-Operated Xmtr/transmitter) or CAT (Computer Assisted Transceiver) control.
Software Setup:
This is the main MMSSTV window. From here you can access all the controls and settings required to use the software.
First, the Audio input and output needs to be setup.
On the Misc tab select the appropriate in and out sound cards. In will be the audio from your radio INTO your PC.
CAT control and other settings
If you are wanting to TX (abbreviation for Transmitter) from MMSSTV then you can setup the PTT control on the TX tab if you want to control this from the software. Remember you can also use VOX if your radio does not support PC control.
If you are using VOX then set this to NONE.
Also, on this tab you should set your Call Sign in the top right box. This will ensure that your call will show when creating templates later.
You can change other settings here which will be specific to your needs / preference. For example, the CW (Continuous Wave as an abbreviation for Morse code) section, when the setting is turned on it will transmit your call sign in CW after the image has been sent.
Receiving A Picture:
Now you have your audio setup you can start to receive and decode images.
Firstly, tune your radio to one of the above frequencies and, on the RX (abbreviation for Receiver) tab of the main MMSSTV window, set the receive mode to ‘Auto’.
You then need to set the input volume level to an appropriate value. You should do this by adjusting the volume control on your radio or data interface.
SSTV image being received in Scottie 1 Mode.
When receiving an image, you should set the volume level to that shown in the image above. The bar will go green when receiving an image. Red if the volume level is too high and gray if no image is being received.
Slant Adjustment
If image appears Slanted this mean you need to correct the ‘Clock’ settings of your sound card in this software. This is because sound cards do not always run at their advertised speed, they could be slightly faster or slower than the software expects. This then creates the slanted image you see below.
Correcting this setting is easy in MMSSTV. If you are receiving an image from someone you know has their ‘clock’ speed set correctly for their TX then this is even better. Sometimes you will have to correct this for each image received as not everyone will have corrected their settings.
To do this, all you need to do is go to the ‘Sync’ tab and click on the picture of a face.
This should then correct the slanted image in the window above. You can then click the ‘Mem’ button and this will save this corrected value into the software settings. For future images you can just click the face each time, the slant shouldn’t be too bad as you saved an initial setting into the settings with the first image.
Saving received images
Received images can be saved externally from the program for future use.
Go to the history tab and on each image you want to save, right click, and select one of the two save options. with time stamp adds a received time / date overlay to the image.
Transmitting a Picture
Templates
Transmitting a picture is just as easy as receiving. You can also customize your transmitted picture however you like.
On the ‘Template’ tab, at the bottom half of the window click on the ‘S.pix’ tab and drag onto each square the different background images you would like to transmit.
Then in the preview window above click on any of the pieces of text to edit its content, colour, size etc. you can also use a ‘macro’ which will automatically fill in with the other person’s call sign, etc. when using the log book feature.
Once you are happy with your layout click on the ‘S.Templates’ tab in the bottom half of the screen. Then click anywhere in the preview window and drag and drop into one of the blank squares. To overwrite an existing template by just dragging to one which already has one saved in it.
You can switch between each of the templates and background images by just double clicking on the relevant square. You can choose any combination of template and background image.
Transmission
Before transmitting the first thing to do is to get the volume set correctly. If using a direct cable from the headphone socket to the radio then in your computer task tray, turn the volume down to 0 before your first transmission.
You then need to select the mode you want to use, select which template and background image you want to send and then click TX.
Then you need to slowly turn the volume up in the system tray so that the audio level into the radio DOES NOT show any ALC (Automatic Level Control) activity. If ALC is active, it could distort the signal, and make it difficult to decode at the other end.
Next to the TX button is the option for a 1750hz tone and the button to turn off / on the CW call sign beacon after the image has been transmitted as mentioned above in the settings section.
12 comments on “A Guide to MMSSTV”
Many thanks for your work.
It was a good help to get my SSTV up and running 🙂
vy 73 de Rolf -DJ7TH-
Carl
Very good information on the setting up of MMSSTV.
However, do you have to turn on vox on your radio? when vox is selected as shown above.
Best Regards.
73 de 9Z4CAC
Yes, if you are using VOX then you will need to set it on your radio. Same as if you were using a mic. If you are using the rear data port to connect to your pc you would need to check the VOX will work. Some only work with audio going in the mic socket.
Karcsi
Hi dear om.
I have a problem where the reception starts, but stops after a few seconds.
The broadcast is perfect.
Can you help me find out what the problem might be.
tnx 73 HA5OKE
op Karcsi
Thanks for the guide! I’ve just started to learn about SSTV thanks to a couple of operators at my local club (TARS). We decided to do a demonstration to the club a couple of weeks ago, and after a bit of aggro getting the settings right, we had a very successful evening.
We were both using Yaesu FT817’s and initially ran into problems getting the rig to transmit, it would go into TX but nothing was being transmitted, finally we realised that the radio needs to be set to ‘Digital’ using the mode buttons – if you don’t then none of the audio from the laptop is picked up, as the microphone is still active. I presume this will be the same for the FT818 as well. I hope this little nugget will be helpful to somebody and save some head scratching 🙂
73 Lin M0TCF
Harry
thanks for a great guide to setting up MMSSTV.
I have been using it for years on many laptops and desktops.
All of a sudden i’m getting “can’t update pdf” error.
the only way i can stop getting it is turning off history, then i lose the picture.
Any help would be gratefully received
Thanks Harry VK4TK.
Ken foster KD5HLO
I am using a digirig on an ICOM 706. Every thing works but it won’t transmit; there is no red lite or any thing on the radio showing output.
Curt
When i click receive my transmitter is apparently transmitting. Can’t receive images?
W0GRC
Bruce Light
Hi
Just got back into SSTV. I am unable to retransmit the RX pic. I cannot find the small box in the templates. Do you know how to code that into the template?
73
Bruce
VE7BSM
Hi
Yes, to get the RX picture in the display you add a picture, ‘Draw Picture’ next to the Add Text Button. Then in the popup select ‘Refer to the History’
Stephen
M5SJM
Donald P. Feldman
DO YOU HAVE THE COMPRESSOR ON OR OFF WHEN TXing A PIX?
The Compressor should be OFF. As with other digital and data modes the signal should be as unmodified as possible.
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