Topband: First K2AV FCP in WVDXA Commissioned

[Charlie Young]

On Saturday I helped commission what could be the first of several K2AV folded counterpoise setups in WVDXA (West Virginia DX Association).   The first counterpoise was built by Tim, K8RRT wth assistance from W8TN.  After it was erected, I took the trusty bow and arrow and installed the inverted L radiator in the trees.   The radiator is about 55' vertical and the remainder horizontal.  The FCP is about 8' from the ground.  The 1 to 1 transformer at the feedpoint was built by Balun Designs. 
 
Adjusting the radiator was uneventful, once I figured out the MFJ 259B was receiving interference from a local AM station.  Tim had one of those MFJ BCI traps, so after reading the manual on this, we were able to tune the antenna.   We did have one self inflicted wound in this process.  The wind kicked up a bit and the temporary LMR 400 flex feedline was blown over close to the FCP while we were in the shack testing with high power.  Suddenly the SWR went haywire.  Oops.  Inspection at the feedpoint revealed about 5 inches of the LMR outer jacket was completely charred by an arc from the FCP to the coax shield.   Guess there are some pretty high RF voltages present on the FCP.  Lesson learned:  keep other conductors, tree limbs, etc well away from the FCP.  I am anxious to see how it behaves the first time it gets wet.  
 
Regarding the radiator adjustment, we started out with a length that, in my experience of putting out more than a dozen of these 1/4 wave tree supported L's, should have been long enough to allow trimming of the radiator.  In fact, the starting length was 5 or 6' longer than we usually go with.  I still had to add 9'.    I suspect this is related to the wire length in the FCP.  When I build one for this QTH, I may increase the wire dimension slightly.  Usually the tree L's around here, with full foilage, will be lower in frequency than they are after the foilage goes away, but this one was higher.   It was not a big deal, we were able to get good results. 
 
Normally, I just cut the radiator (#12 or #14 THHN) to 130' and do the final adjustments by trimming the elevated radials.  Nomally, in my location and in my trees, the elevated radials end up approximately 120' long.  I might try to adjust the FCP length on the next one just to see how it ends up.  
 
K8RRT was using an inverted L, same location as this one, over a single elevated radial about 5' or 6' over ground.  Tim started on CW in 2008 and with this simple antenna has confirmed 160M DXCC.  His first DX QSO with the FCP was CY9M, in just a few calls.  Over the next few days, as Tim's work sked permits, we will do some RBN testing to see what, if any, performance conclusions can be drawn.  
 
I have had really good performance with these tree supported Ls  using two to four elevated radials, and am anxious to try the FCP here. 
Even if they are just equal to the elevated radials, the reduced footprint will make room for more rx antennas. 
 
Thanks to K2AV and W0UCE (who I met in Dayton this year) for the work on this. 
 
73 Charlie N8RR