Re: LoG antenna trick
Posted: Tue Jun 14, 2022 8:29 am
Forgot, if someone is interested in antenna modeling using NEC, or wants to play with the free 4NEC2 modeling program, here's a NEC model for the LoG antenna
to use it, just copy/paste the above in an editor and save it as LoG.nec, then load the model in 4NEC2 and you'll be ready to play with the simulations; notice that in the model the antenna wire is sligtly raised from ground, since otherwise NEC will complain about the fact that the wire is too near to ground, nothing particular, just to let you know; also, I slightly changed the loop length after running the NEC optimizer, the original sizes are after the "::" in the inline comments
Code: Select all
CM ---------------------------------------------
CM File: LoG.nec
CM Loop on Ground - http://www.kk5jy.net/LoG/
CM antenna length changed using optimizer
CM feedpoint impedance set to 450 Ohms
CM ---------------------------------------------
CE
' symbols
SY freq=1.800 ' test frequency (MHz)
SY totl=21.336 ' loop perimeter (mt) :: 18.288
SY leng=(totl/4) ' square loop side (mt) :: 4.572
SY wire=0.00075 ' antenna wire radius (mt)
SY hght=(wire*3.3) ' height from ground (mt)
SY segs=25 ' total segments for each wire
SY fnum=1 ' feedpoint wire #
SY fseg=1 ' feedpoint wire segment #
' -------------------- antenna wires ---------------
' # segs x0 y0 z0 x1 y1 z1 rad
' -- ---- ---- ---- ---- ---- ---- ---- ----
GW 1 segs 0 0 hght leng 0 hght wire
GW 2 segs leng 0 hght leng leng hght wire
GW 3 segs leng leng hght 0 leng hght wire
GW 4 segs 0 leng hght 0 0 hght wire
' ground parameters
GE 1
GN 2 0 0 0 13 0.005
' wires loading
LD 7 0 0 0 2.1 wire ' insulator
LD 5 0 0 0 58000000 ' copper
' antenna feedpoint params
EK
EX 0 fnum fseg 0 1 0 0
' test params
FR 0 1 0 0 freq 0
' end of model
EN