[ARC5] Selectivity ratings of ARC-5 receivers.

[Kenneth G. Gordon]

Reading the ARC-5 maintenance manual, I see that the selectivity for, say, 
the R-26 (3 - 6 MHz) receiver is listed at 7.3 Kc at 2X, and 26 Kc at 1000X.

Now 1000X is 60 db, but isn't 2X 3db and not 6db?

Color me confused at this point.

My thinking is that in order to achieve a 3db increase in signal level at the 
receiver, the transmitter must be doubled in output power, given identical 
conditions.

Or am I all wet here?

Ken W7EKB