This is a design I’m currently working on based around a 12m Spiderpole.
Unfortunately the 12m Spiderpoles are out of stock so I can’t actually get on and build this antenna. It’s a pretty basic design that’s put together around a standard 49:1 Unun and a half wave of wire for 10.125Mhz.
The antenna consists of 14.8046m of wire, 12m of which is vertical and 2.8046 horizontal from the top.
The 3D field plot shows a pretty much circular radiation pattern with the typical null in the centre.
Looking at the elevation slice there’s 5.53dBi of gain at 5 Deg, ideal for DXing.
It’s worth noting that a fully vertical 14.8046m EFHW antenna for the 30m band would give 5.81dBi at 5 Deg so, the inverted L is only 0.28dBi down on gain and the overall radiation pattern is pretty much the same.
As soon as I can get my hands on a 12m Spiderpole I’ll get this antenna built and on air.
Summary:
Total Wire Length: 14.8046m
Vertical Wire Length: 12m
Horizontal Wire Length: 2.8046m @ 12m above ground
Wire Dia: 1.5mm
Feed Type: 49:1 Unun or simple LC impedance matching circuit
Impedance: 50 Ohm
SWR: <1.5:1 across whole band