M2 Helical Antenna

I have a couple of questions and a comment about the new M2 helical antenna.

  1. has anyone found a good mast/mount for use with the antenna?

  2. does anyone know the size of the screw holes in the bottom of the antenna?

I’d love to see Emlid ship the unit with two screws for the antenna and offer a mounting solution since it’s not as easy to find a solution as with a patch antenna.

Should also note that the link to the antenna model in the Documents section does not seem to work.

Cheers

What are you trying to mount it to?

Hi,

It should be a standard female SMA antenna port at the bottom. It is designed to thread right onto the connection in order to mount.

M2 will be used on a UAS based on Foxtech Hover 1 frame.

Indeed, I was just curious why the additional two small-diameter holes on the bottom were present if not for more secure mounting.

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I think it would be tough to make a custom universal mount due to the fact that each quad model is going to have to be specifically positioned to be in line with the sensor. That frame looks like a pretty open platform so I would think it would be fairly easy to mount with common hardware.

If only that were the case. ‘Common hardware’ is essentially all geared toward patch antennas with a cable path exiting the side of the module. In most instances the cable is then run down the length of the commodity folding antenna mast. This is not possible with the helical antenna and requires a more customized solution. Most people will be looking to find a 3D-printed mast designed by a talented, interested builder. It would be nice to have an option or even a recommendation from the manufacturer.

I may be wrong, but a helical antenna does not usually require an additional base plane so all you should need is a component to get it just off the chassis and an elbow adapter. You can reference the mountings on the P4RTK and all other retrofit kits for the standard Phantom 4 Pro.

Do we know what the thread is for the mounting holes?

Rubber Standoffs

Do you have access to a 3D printer? I’m thinking it would be trivial to design a mast out of 12/10 or 10/8mm carbon fiber tubing and a custom plate to screw the antenna to at the top. The cable can then go through the tube and down to the drone guts.

Any decent modeler could whip this out in a couple hours max.

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No base plane is required, however it is recognized that increasing separation from potential EMI sources will produce the best results.

Thank you very much for the information on the rubber standoffs. I’ll pick some up.

I’m sure I can find one and a student to complete the task. I have no experience with 3D design and little time to add it to my skill set at the moment (but I’d like to). I’ve got a couple leads already, I was just hoping someone knew of a readily-available solution.

In the name of innovation I wouldn’t hesitate to spend $15-20 on simple hardware to create a custom mounting vs $100 for a custom 3D print. While EMI can affect the compass there shouldn’t be anything on the drone throwing that much of an EM signal to affect this higher grade GPS. I refer back to the Phantoms. The are mounted millimeters from the main board and are much closer to the speed controllers and motors that your setup would be and they seem to be working all day long.

Fair enough. I concur with your sentiments and may try a more direct attachment and evaluate the results. I appreciate the feedback, thank you.

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For sure. I’d love to see how it turns out. We are getting tired of mass manufactured aircraft and I have been researching more open platforms so you’ll be teaching me a thing or two.

EMLID_ANT107_dimensional_specs

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Super, thanks! That’s the file that didn’t seem to be properly linked I assume.

Hmm, M2.5 seems to be a very difficult size to find for the rubber standoffs.

What about using slices from a length of rubber/silicone/etc. tubing?

Certainly could do that, o-rings would also work. The rubber standoffs that screwed in just seemed so fit for purpose.

Oh, I see. They are threaded ends with rubber molded in between. Yes, I can imagine they would be hard to find in 2.5mm.