Topband: Preamp filter insertion loss

[Doug Waller]

>> A 7-pole Chebyshev high pass filter will be placed in the circuit, before
>> the preamp.

>Watch the loss there, which mostly relates to inductor Q and component and
>design tolerances.
>Are you sure you need such a large filter before the amp??

Having originally shrugged this statement off,  I subsequently decided I
must be missing something.

Say a 20 dB preamp/filter has an insertion loss of 3 dB and is installed at
the receive antenna feedpoint.  My initial opinion was that the weakest
signal in the passband would merely be attenuated 3 dB and that the preamp
would then amplify the filter output 20 dB, for a total gain in the weak
signal level of 17 dB.

Since virtually all commercial preamps have some kind of pre-filter
installed, I am now thinking that mebbe the addition of a 5dB preamp before
the commercial preamp/filter would enhance the S/N ratio of very weak
signals.

This morning I thought the phased loops should have heard the DX, but only
KH6AT was booming in.

All thoughts appreciated.

73, Doug / NX4D