[TowerTalk] 2m intermod filter placement

[Jim Lux]

On 5/11/14, 12:01 PM, Joe Subich, W4TV wrote:
>
> It depends on whether the preamp is generating the intermod or the
> IC-9100 is generating the intermod.  If the intermod is due to mixing
> in the IC-9100's internal preamp, put the notch filter between the
> LNA and IC-9100 so it does not impact the system noise figure.
>

worth trying for a quick initial test. The filter in front of the LNA 
will degrade the noise figure a bit (or a lot.. what's the loss of the 
filter at 144 MHz?)

  But I'm going to bet that the odds are that the intermod is in the LNA;
if the signals are strong enough that he's getting intermod in the 9100, 
he doesn't need the LNA, or it has too much gain (and then, put a pad in 
series between lna and rx)