Topband: L/FCP Design Questions

[James Wolf]

Bill,

Here's my thoughts, although not fully comprehensive. 
The crank up adds some additional complexity, so there are a few mechanical problems that I'm not familiar with.   I'd be hesitant to put an Inv-L up only if you cannot electrically get a stable shunt fed system working.  The problem is that of an "Inv-L" working that close to the tower, therefore you would absolutely want to detune the tower. The problem with doing that is the same as using the tower in a shunt fed fashion, so I suspect if you can solve that problem, then the shunt fed method would be best.  If you don't solve that problem then any coupling between the tower and the Inv-L will change your resonant frequency and SWR if/when electrical continuity between tower sections changes.  If you can solve the section connection problem, then before detuning the tower, you would want to ground the shield of the coax at the top of each section.  As for the control lines, you should be able to adequately use chokes to decouple them from acting like a parasitic element.  

Jim - KR9U


<<< I'm planning on putting up a 160m Inverted L along with the K2AV FCP.