[VHFcontesting] rf problem

[G0MIC at aol.com]

You might well solve this by putting a 1/4 wave coax stub at the input of  
the masthead amp.  It needs to be shorted at the end away from the junction  and 
the length has to be adjusted for the velocity factor of the cable you are  
using.  The better the quality of the coax the better (sharper) the  filtering. 
 Using a poorer quality coax increases the bandwidth of the  filter.
 
Let us know how you get on
 
Regards
 
Malcolm
G0MIC