[Antennas] half sloper

2002年7月25日 13:42:46 -0600

I'm looking at building a reduced size half sloper for 160m based on 
WD8DSB's article in March 1998 QST.
http://www.arrl.org/members-only/tis/info/pdf/9803054.pdf (if you're 
an ARRL member). 
I'm considering moving the loading coil to the low end of the sloper as 
it seems this would help get the maximum current amplitude on the 
sloping wire, thus increasing radiation.
Another more radical idea I'm considering is using the coax shield 
itself as the vertical portion of the sloper (no tower here). The 
process is that if the coax shield was connected to the radial ground 
plane at ground level and a choke balun was placed immediately after the 
radials on the transmitter side, currents would flow on the outside of 
the coax only on the vertical portion.
It seems the weakness to this thought process is:
 The coax is still going to want to act like a transmission line so 
minimal current will flow on the outside of the coax. If this is the 
case, then the sloper would not work correctly. The solution to this is 
of course to add a seperate vertical wire but I'm hoping to avoid that.
Any thought from the group?
thanks,
chris, n4vi
boulder, co