New 3D printable antenna base and placement template

I have put up on Thingiverse a 3D printable design for mounting the Kraken set of magnetic base antennas. The mount may not be suitable for permanent outdoor mounting of the antennas, but should work well for temporary and indoor installations. A variant of the design serves as an alternate placement template for positioning antennas on a car roof. Source files for OpenSCAD are provided so that the design can be tailored and adapted. STL files are provided for different maximum radii from 100 to 350 mm.

Link to Thingiverse: https://www.thingiverse.com/thing:5771678

For my part this design will make it easier to demo the Kraken as part of outreach related to ham radio. I hope that it will also be useful to others. I include some photos of my Kraken installed in a plastic case for transport, complete with a tablet. I have enclosed an OpenSCAD source for the protective cover over the tablet, in case it is of interest to others. Most likely you will then have to adjust parameters in the code to the dimensions of your tablet.

Torbjorn Skauli, LA4ZCA

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I see there is no ground plane. How is the performance compared to a car-roof mounted array?

Awesome setup and thanks for uploading the modified array to Thingiverse. I’ll have to print one out too.

Is the pictured array designed to sit on top of a mast?

Indeed, there is no ground plane. I considered making the antenna base out of metal, or to add conductors along the arms, but I suspect that it would not make much difference since there is already ground in the outer conductor of the cables. It is conceivable to make an arrangement of grounding wire connected to metal clips attached to the antenna bases, but, as far as I understand, that would either have to be large or to be made resonant at a particular frequency. Lacking proper ground, the antennas will be nonresonant, which should be tolerable for receive as long as signals are not too weak.

One thing to worry about would be that the effective phase center of the antenna is at a smaller radius than the antenna whip, since it forms a kind of dipole with the cable running inwards. Thus perhaps performance could be improved simply by changing the radius setting. Unfortunately I may not have the time, equipment, or competence to figure that out.

OK, let us know how it works for you. There are mounting holes in the hub that can be used to attach it to a mast. As long as it is not too stormy that should work.

Very cool! I’ve been thinking about remixing the template to make the holes every so slightly larger so that they don’t grip the rubber of the mag mount. The semicircles are actually a great idea too, so you won’t have to worry about grabbing the wires. I like this a lot!