Hello,
I made a version of this antenna, but with slightly different dimensions found here:
I also added ground plane, as I read somewhere that that is a good idea. I used 1,6mm diameter single copper wire and 32mm PE drain pipe. I cut grooves in in the drain pipe to get the circular N chassis connector with the ground plane wires sticking out. Then cut a small piece, approx 20mm with a groove, to use as insert to hold the antenna in place, but also to strenghten. I plan to use a joint to extend the pole with the antennae cable going inside. It will be 2 meter cable in to the gateway at my loft.
Tuned the antenna by inside the PE pipe to get good VSWR at 868Mhz:
And this is the return loss (I think) using NA mode:
This all looks good to me, but I am not an expert on antennas.
When I widen the bandwidth using NA mode, I see this:
This may be harmonic, I dont know, or I have made the antenna all wrong?
It was fun making this antenna, so I decided to make the ground plane antenna:
I did this the same way as the collinear using circular chassis N and cut grooves into the PE pipe:
Tuned it in the drain pipe and got this:
VSWR
dB
Next step is to try both antennas and see how they perform using a node.
Maybe I will try the J pole as well, but from what I have read, the Ground plane or Collinear seems to be good.