Thursday, March 07, 2019

Radio to Phone coupling for SSTV Reception

The two SSTV images received from the ISS (see previous posts) were decoded using acoustic coupling. The Icom ID-51 has the ability to record the audio on to an SD card, so i wondered if i could do better with direct coupling using a cable. After some investigation I settled on a minimalistic circuit. See below.

Update: the 82k resistor should probably be 500k.  I'll need to investigate some more.

The first image was the original  (using acoustic coupling ) and the the second was using my homemade cable. As you can see, there was a significant improvement .

Acoustic 

Cable

The phone was an android Samsung S9 using the Robot36 app. A think the circuit would work on any android device .

Note: There's no reason why this circuit could not be used for APRS reception using APRSdroid.

I take no responsibility for any damage to your toys, so play at your own risk.

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