[Premium-Rx] Thanks Again: 8618B-(S1)

[stephous]

Thanks again to all who responded to my requests for information. Without
your help many radios would never be fully restored.

The new 8618B-(S1) is now working perfectly. A dip switch was set
incorrectly disabling ISB-2. I didn't know I had ISB-2 until someone pointed
it out. Exactly what is ISB-2? It appears to be sharper filtering for side
band demodulation. Part of the option brings out separate USB and LSB
connectors at the rear panel. When the SSB key is depressed these outputs
are active and the receiver defaults to the 6.4 KHz roofing filter. The
filters on the ISB-2 card are 2.2 KHz (I took pictures of the card when I
had it out). BITE no longer hangs on RF tests.

ISB 796304-1, Filters;
p/n 92217 10.7 MHz / 3.2 KHz USB
p/n 92218 10.7 MHz / 3.2 KHz LSB

ISB-2 796304-2, Filters;
p/n 92321 10.7 MHz / 2.2 KHz USB
p/n 92322 10.7 MHz / 2.2 KHz LSB

On an audio analyzer you can see the difference between the 3.2 KHz and 2.2
KHz filters . You can definitely hear the difference.

Best Regards,
Steve Pappin