Just an idea for SSTV

There was an interesting circuit in the latest Radcom from the RSGB for a receiver for 14MHz PSK31 digital signals. This got me thinking that something similar could be used for SSTV.

The receiver is an RF amplifier, followed by a crystal filter and balanced mixer, whose output goes directly to an AF amplifier.

The transmitter is a balanced mixer driving an output stage.

Here it is:



The AF input and AF output are connected to an iPad using a Griffin iMic interface. The iPad is running Blackcat systems SSTV software which can both receive and transmit.

I have not yet worked out the RX/TX switching, and it occurs to me that I don't need two 14230kHz oscillators, one would do. So the TX oscillator could feed the RX mixer…