[Elecraft] help requested

[luc kerkhofs]

Hi all,
 
I think I may have a problem with my K3 . I was checking my beverage antennas last week and I decided to see
if I could hear signals on my coaxes going to the beverages .
 
At night I can hear signals up to S5 on 80 m with 50 feet of coax connected to the receive input jack , coax end is open and is going underground except for the last 8 feet .
I have band reject filters inline on my TX antennas and when I manually switch the filter and TX antenna to a different band 
I can barely detect the stations that were S5 before . I tried the same with my other radio and the stations I hear are not moving
the S meter .  
Did I do something wrong in assembling the radio ? 
 
Thanks for helping out
 
73
Luc
ON4IA