The Explora decoders all have 3 tuners and are designed to work with a connection to the Unicable ports on the SLNB, and NOT to the Universal ports. Hence, you MUST move the cable used for the 5a decoder from the Universal port on the SLNB to Port B on the SLNB, assuming the Explora 1 is connected to port A. If the Primary is indeed and Explora 1, then a diplexer is required behind the Explora 1 for inserting the HB signal onto the SLNB cabling. The other way to do the connection is to use a separate cable from the Explora I connected to one of the RF ports on the Explora 1, with a diplexer behind the Explora 3A to insert the Hb signal into the unicable port on the Explora 3A. Then you need to set the UBs used by the Explora 3A NOT to clash with those used by the Explora 1, which would probably on UBs 0,1,2. These settings are also referred to as the "Decoder 1" settings when used with the installation wizard. Set the Explora 3A to use "Decoder 2" settings which are UBs 5,6,7 for best results. The frequencies for each UB are: "Decoder 1" UB 0: 1210 UB 1: 1420 UB 2: 1680 "Decoder 2" UB 5: 1057 UB 6: 1108 UB 7: 1159 once you have made the cabling changes and the settings chnages, everything should now work.
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