Micro Motor Community

REALLY lightweight dipole! Ultralight antenna


#21

Sorry image got stuck!


#22

You’re absolutely right, the fresnel zone has a big dead area leaving the top and bottom of a dipole - but we often compromise on placement as the dipole itself tends to not be the best thing to crash on.
I lay my dipole down flat parallel to the frame axis, and in forward flight the bank angle sends my dead zones up in the air off the back and down into the ground in front.


#23

@davidpulvermacher: Yes, of course. Antenna range is reduced in extension of its longitudinal axis (Fresnel zone). However, two factors speak against mounting the antenna vertically above the frame. First, as @NotFastEnuf points out, we want to protect the antenna in crashes. Second, a fast-flying quad will pitch forward to a significant degree, sometimes approaching an 80 degree tilt. Both of those reasons are why you often see racers pointing their vTX antennas out the back of their FPV racing quads.

In terms of practical priorities, it’s better to compromise the radiating pattern of the antenna when you are sitting flat, close to you at the start. Then you can optimize antenna placement to be close to vertical (in relation to the ground, not the frame) in fast forward flight (FFF).


#24

Meanwhile a vertical orientation means you get a poor signal if you fly over yourself. Not an issue indoors in a single story house, but a potential one outside.
It basically comes down to the kind of flying you’re doing. If it’s a lot of outdoors a cloverleaf is a good idea.


#26

The stock dipole on my Wolfwhoop Wt05 wore out, so I gave this a shot. Even with haphazard test measurements and positioning, my reception is WAY better than it’s ever been! I now have access to fly around the entire house, except for one room.

That facinates me :nerd_face:
Now I’m starting to study antenna theory to try and understand why, with hopes to eventually adjust things to get better reception from my favorite place to relax (that one room), so I can fly from there. Reception in that room is bad in general. Maybe I can fix that.

I have to use a range extender to get a decent wifi signal in that room. Does anyone know if it would be possible to create some type of “bridge” antenna (or extender), to bounce Tx and Vtx signals into problem areas?


#27

Awesome!
It always worked really well for me too.
Your old one may have had broken “ground” coax at the base, that’s typically the first thing that fails on mine, and causes serious signal loss.

Psyched to hear it worked well for you!

Extender wise, not really, other than running coax through your house to put an RX antenna at the other end and using diversity on your video RX to have to watch both near and far antennae.
Bit of a pain though!


#28

I quickly learned how important that coax ground was. Getting that soldered was the hardest part on mine. Seems to be holding…for now.

Thanks for the extender suggestion! Sounds like my time could be better spent on some other project.