Notebook PSK - SSTV Interface

Use a metal enclosure to ensure maximum shielding. Chassis mount the microphone connector (8 pin male) to the metal enclosure. Cord mount all other connectors.

PL1 - This is a Mono Plug and it is cord mounted. It has a tip and a ring only. Connect the tip to a center conductor (it's OK to use multi-conductor cable, as long as it is shielded) of a length of shielded cable. Connect the other end of the conductor to one of the leads on the 8 ohm side of the 8:100 transformer. Connect the shield to the ring of the plug and connect the other end of the shield to the remaining lead on the 8 ohm side of the 8:100 transformer. Do NOT connect the shield to any metal parts inside the enclosure.

PL2 - Make sure this connector is a Stereo Plug. It has a tip, center ring, and ring. Connect the center ring to a center conductor of a length of shielded cable. Connect the other end of the conductor to one of the leads of the 1000 ohm side of the transformer. Connect the shield to the ring of the plug and connect the other end of the shield to the remaining lead on the 1000 ohm side of the 8:100 transformer. Do NOT connect the shield to any metal parts inside the enclosure. Do NOT connect the tip of the plug to anything. Some computer sound cards use the tip connection to supply voltage to electric microphone elements. In these cases, the audio input is only taken from the center ring connection and usually available as left side or monaural only. Do NOT connect the center tap of the transformer to anything.

PL3 - Make sure this connector is a Stereo Plug and do not connect the center ring to anything. If a Mono Plug is used, the right channel output will be short circuited to ground , causing severe distortion on the output signal. Even though the sound card has two output channels, only use one of them. Connecting both of them together will cause serious distortions and possible damage to the sound card. Connect the tip to a center conductor of a length of shielded cable. Connect the other end of the conductor to the white lead of the 1:1 transformer. Connect the shield to the ring of the plug and connect the other end of the shield to the black lead on the 1:1 transformer. Do NOT connect the shield to any metal parts inside the enclosure.

The microphone connections that are shown are adequate for most Kenwood transceivers. CHECK CONNECTIONS FOR YOUR RIG and make necessary corrections. Ensure that the microphone cable shield IS connected to the metal chassis. In this case the shield for Kenwood rigs is pin 8 (the center pin). This ensures that the enclosure uses the rigs grounding system. Nothing else gets tied to the chassis!

On the Comm port connector, use at least a 3 conductor shielded cable. Solder the shield to the large "D" shaped metal portion. On the inside of the enclosure, do NOT connect the other end of the shield to anything. Just tape it off so that it does not accidentally short out. That way it will act as an extension of the computer shielding, minimize computer generated interference, and maintain absolute isolation.

The "Wall Wart" transformer provides isolation to the house wiring and power to in order to energize the relay. NOTE: Wall mounted transformers are rated at full load and usually supply a much larger voltage with no load. Since the relay specified has a relatively small current requirement, a wall transformer rated at 9 VDC @ 200 to 450 Ma. supplies adequate voltage and current.

Use high quality "braid over foil" shielded cables. This will reduce the chance of RF interference when transmitting.