[TowerTalk] Coaxial stub filters

Dennis W0JX w0jx at yahoo.com
Wed Jun 25 20:50:06 EDT 2008


List members:
I am trying to make reduce interstation interference for our Field Day operation by utilizing quarter-wave coaxial stubs. I made a 40 meter stub and put it at the output of a TS-850 which was feeding a 20 meter ground plane. The stub reduced 40 meter signal response considerably and had no effect on the rig's SWR indicator or the antenna match.
 
The 40 meter stub reduced the interference caused by the 40 meter transmitter but not significantly. So I put a 20 meter quarter-wave stub on the back of my 1000MP. That did seem to cut down on the 20 meter transmitter noise but the SWR at the output of the MP jumped dramatically. Is this normal? Obviously the 20 meter stub must be putting a considerable loading or reactance on the output of the rig.
Any ideas would be appreciated.
 
73, Dennis W0JX/8


      


More information about the TowerTalk mailing list