Sholto, It is an interesting mail.
Can I QSP it to digitalradio? 73 Patrick ----- Original Message ----- From: Sholto Fisher To: [EMAIL PROTECTED] Sent: Friday, January 25, 2008 5:05 PM Subject: Re: [multipsk] Understanding image transmission I think there is a little confusion creeping in here: "MFSK SSTV" is really a misnomer. It refers to an analog SSTV picture which can be initiated in MFSK16 only. The picture is not sent using MFSK16 modulation in any way, it is just a narrow-band SSTV transmission. Just before transmission, your program sends a "Pic:" command and this switches the remote program into SSTV receive mode. The idea being, you have a nice chat in MFSK16 and when you want to send a picture, you press a button and this starts the analog SSTV picture transmission. After that you can carry on in MFSK16.... The "Digisstv" option in MultiPSK is really a digital picture transmission. It is the encoding of an image in the current mode you are using. So in Packet, the image is broken down into standard AX25 packets and sent that way. In PSK220F it is coded and sent as binary characters (which you don't see). It's a good idea but is limited by the size of the picture and the speed of transmission. The EasyPal & WinDRM SSTV programs are completely digital too. They are based on the DRM OFDM modulation. The MMSSTV modes MP73-N etc are narrow-band analog SSTV modes (similar to the MFSK16 SSTV above). The bandwidth of these is 400Hz if you include the sync pulse. These, Digisstv and the MFSK SSTV mode can be legally used in the data/text areas of the bands now in FCC controlled region 2. The DRM modes cannot and need to be used in the voice area. 73, Sholto KE7HPV.
