Topband: Tunable External Preselector for better Beverage S/N?

[Tom Rauch]

> * His thinking was that the beverage and FT-1000D front end are both
> broad band devices so they will let in additional noise from above and
> below the desired 160M narrow band operating range. 

That is a common assumption, but almost never true. 

Unless out-of-band signals or noise are actually overloading the 
receiver front end or mixers (which would indicate a VERY poor 
receiver), it will make no difference at all.

The noise floor bandwidth is set by the bandwidth of the IF filters in 
the FT1000, not by the front-end bandwidth.
73, Tom W8JI
W8JI@contesting.com