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Using MMSSTV with RS232 PTT

Analog SSTV is still very popular on many ham bands and on CB. One way is to use mobile apps for receiving and transmitting pictures but this “acoustic coupling” between the radio and the encoder / decoder can reduce the image quality. Therefore, using an interface to directly connect the radio with a PC would be better. A popular program for SSTV on Windows is MMSSTV which allows you to control your radios PTT over RS232 DTR/RTS. Strictly speaking you could use an interface built for doing Packet Radio with your soundcard for SSTV now. In my Packet Radio series, I will show how to build these interfaces in the future. For this blog post I will describe how to set up MMSSTV with RS232 PTT.

Downloads

You only need to download the MMSSTV software here .

Setting up the software

After installing and starting MMSSTV click on “Options --> Setup MMSSTV(O)” to open the options window. On the first tab (RX) nothing should be changed. On the TX tab you should enter your callsign. This is automatically added to pictures. In addition, MMSSTV automatically generates pictures for calling CQ or saying 73.

To activate RS232 PTT, now click on "Radio command" in the “TX” tab.

On the new window, select your serial port (you can find serial devices your COM-Port number in the windows device manager) and tick DTR/RTS. Everything else should stay as it is. Finally close all windows by clicking on “OK”.

Using MMSSTV

The main window of the program is quite simple to understand. The RX window allows you to receive images. Reception is automatically started as soon a SSTV signal is detected on your microphone input. Moreover, MMSSTV automatically selects the correct mode in the TX and RX tab when a picture is received.

Warning: The images are only saved temporarely. To keep them, right click on a picture in the history tab and then click "Save to file".

Selecting a picture on the TX tab can be easily done by copy and paste. Simply copy a picture in Windows Explorer and then press CTRL+V in MMSSTV or click on the clipboard symbol under the picture display (in the template tab). To start the transmission, click on the TX button (on the left side under the picture display in the TX tab).

Warning: It seams that MSSTV only works with JPEG images. PNGs can't be loaded.

Of course, MMSSTV has many more functions but what I described here should be enough for basic operation. Simply play a little bit with the program and you will see what else it can do.

Update: MMSSTV can be used as repeater as stated on the programmers website .

Received photos

Here I want to show you what I decoded with MMSSTV so far.

Ham Radio

Most of these pictures came from the Oscar 100 satellite.

CB-Radio

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last edited 26th Oct 20