[amsat-bb] 70 cm Lindenblad progress - notable support structure for parasitic elements

[Paul Andrews]

I built a patch feed for 1296 MHz and a folding fabric dish using many 3D
printed parts.  I have some experience testing parts under stress in hot
weather.

PLA is great for prototyping but will fail quickly outdoors and then be
eaten by squirels and deer.  :0

Nylon is strong but softens significantly in heat.

ABS or PETG are UV stabile and relatively heat resistant.   PETG is great
because it prints straight and strong.

3D printing will be a game changer for ham antenna builders.

73 - Paul - W2HRO



On Tue, Sep 22, 2020, 21:27 Curt Laumann via AMSAT-BB <amsat-bb at amsat.org>
wrote:

> Sure Stefan, et al, I'd be happy to share the STL file.  I used FreeCAD and
> will make those files available as well.  I'm sure others can further
> improve the design.
>
> I printed this part out of eSun PLA+, but a better choice for outside use
> might be PETG.
>
> Regards,
>
> Curt / K7ZOO
> Tucson AZ
>
> On Tue, Sep 22, 2020 at 6:07 PM Stefan Wagener <wageners at gmail.com> wrote:
>
> > Very nice! Will you make the STL file available?
> >
> > 73 Stefan, VE4SW
> >
> > On Tue, Sep 22, 2020 at 7:46 PM Curt Laumann via AMSAT-BB <
> > amsat-bb at amsat.org> wrote:
> >
> >> Hi All,
> >>
> >> Over the past few months I've been designing & assembling a few 70 cm
> >> Lindenblads.  The current version is shown in the attached picture (link
> >> below).  Arrow shafts are used for parasitic elements.  The shafts are
> >> bonded in place with fiberglass resin.  Rubber end caps (from McMaster)
> >> cover the shaft ends.
> >>
> >> The notable part of this design is the central structure (supporting
> >> parasitic elements) is 3D printed as *one part*.  Virtually all of the
> >> angles and spacings are achieved in the 3D printing process.  After
> >> struggling to align and bond various PVC and irrigation parts in other
> >> versions, it was a breeze to assemble this design:  one nylon machine
> >> screw, one nut, four bonding points.
> >>
> >> The design could be easily modified to accommodate 0.125 inch diameter
> >> parasitic elements as well.
> >>
> >> Regards,
> >>
> >> Curt / K7ZOO
> >> Tucson AZ
> >>
> >>
> >>
> https://drive.google.com/file/d/1i2c6T5lZtI00KChbJuyphvvechzBvlNw/view?usp=sharing
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> >
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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>